APPLE Me MODEL A2S2064 CC10 SAMS. Remove staples and use cover for file folder. COMPUTERFACTS™ put easy to use, informative technical data right at your fingertips. Each edition includes specific service information on the individual component, along with some overall troubleshooting hints. The following information is just a sample of the many valuable time saving features contained in this exclusive Sams COMPUTERFACTS publication: Preliminary Service Checks section is an easy to use, step by step guide for the experienced technician or hobbyist, and even beginners. SAMS famous industry accepted standardized notation schematics containing CircuiTrace 8 , GridTrace™, waveforms, voltages and stage identification. 3T • Ste p by Step Troubleshootin g guides the technician through the necessary procedures to quickly locate the problem. TROUBLESHOOTING MtCSOPBOCCSSOB CHIP (CPU) OPERATION Ve«t> Irte processor is lunclion>ng by electing ihe signals on the address Ones ipms 10 tf»u 24 of IC UGOOl and me dala ■ 1<nes(p*ns 41 llwu 5fi| using a fogic proee or a scope if a logic prooe "S used reler lo Ihe 'Logic Chan" for Ihe correct readings u a scope >s jsed. me *a»etorms on me address inesie.cepi cms 22 and 23*nicn have no signal in Po*e< Jp model should be similar lo Figure I The waveforms on Ihe data lines should be similar to Figure 2 • Log ic Chart containing logic probe readings to isolate defective circuitry and components. LOGIC PIN IC PIN IC PIN IC IC IC IC IC IC IC IC NO. UI0O NO. U100 NO. U102 U103 Jl 04 UI05 U106 UI07 U108 UI09 1 p 21 P 1 L L L L L L L L 2 p 22 P. 2 P P P P P P P P 3 p 23 P 3 H H H H H H H H • Quick Component Location using the SAMS exclusive GridTrace, CircuiTrace, and component photographs. 5 6 lv 3 7 10 n 12 • Complete Components Parts List in an easy to use format with field replacements shown when possible. SAMS unique semiconductor, chip and IC cross-reference gives you many replacements to choose from and is available at your Electronic Distributor. SEMICONDUCTORS (Select replacement for best results) ITEM No. TYPE No MFGR PART No REPLACEMENT DATA ECG PART No GENERAL ELECTRIC PART No MOTOROLA PART No NTE PART No RCA PART No WORKMAN PART No ZENITH PART No. 0102 1SS53 1 149-2576 ECG5I9 GE-514 IN4935 NTE519 5K9091/I77 HEP925/519 103-131 D103 1 N50 E * 1149-2527 ECG 109 1N60 NTE 109 SK3068 WEPI 34/109 10 3-Z9C0 1 D201 1N4004GP 1201-4205 ECG1 16 GE-504A 1N4004 NTE116 SK33I 2 WEP157 212-76-02 0501 thru ISS53 1149-2576 ECG519 GE-514 , 1N4935 NTE519 SK9091/177 WEP925/5I9 103-131 D*03 CircuiTrace ts o registered trodemork of Howard W. Sams & Co., Inc. , COMPUTERFACTS and GrioTrace are irademarlcs of Howard W Sams & Co., Inc. Apple is a registered trademark of Apple Computer, Inc. To order, or for more information see your Sams Distributor, or telephone 800-428-SAMS. SAMS,. Howard W. Sams & Co. A Division of Macmillan, Inc. 4300 West 62nd Street, Indianapolis, Indiana 46268 CC10 08920 ISBN: 0-672-08920-3 Apple Me Main Logic Rev A Apple P/N 661-94119 (Replaced by 91 084) See Note NOTE: 820-0064-A at the top middle of board is the revision number. This is the original Apple Me board. Apple lie April 1986 1.2.1 Apple lie Logic Board Unenhanced Apple P/N 661-91084 NOTE: If the 6502 has been replaced by a 65C02, the 342-01 34 by the 342-0303, the 342-0135 by the 342-0304, and the 342-01 33 by the 342-0265, the board has been upgraded to "Enhanced." Any other ROM configuration is NOT acceptable. Apple lie April 1986 1.2. Apple lie Logic Board Enhanced Apple P/N 661-0283 65C02 VIDEO ROM 342-0265 _J I EF ROM 342-0303 I CD ROM 342-0304 NOTE: If the 65C02 has been replaced by a 6502, the342-0303 by the 342-0134, the 342-0304 by the 342-0135, and the 342-0265 by the 341-0133, the board has been down- graded to "Unenhanced." Any other ROM configuration is NOT acceptable. Apple Me October 1986 1.2.3 Apple lie Logic Board Enhanced Apple P/N 661-0283 NOTE: This board can be identified by a) the CF ROM and b) the 64 x 4 RAMs. Apple lie October 1986 1.2.4 SAMS COMPUTERFACTS APPLE MODEL lie PRELIMINARY SERVICE CHECKS HI — — I -I Q_ HI Q. Q < o o o This data provides the user with a time-saving service tool which is designed for quick isolation and repair of Com- puter malfunctions. Check all interconnecting cables for good connection and correct hookup before making service checks. Disconnect all peripherals except the Monitor from the Computer to eliminate possible external malfunctions. Replacement or repair of the power supply board, main board, disk II interface board, keyboard, or connectors may be necessary after the malfunction has been isolated. TEST EQUIPMENT AND TOOLS TEST EQUIPMENT TOOLS Digital Volt/Ohm Meter Logic Probe Frequency Counter Monitor Phillips Screwdriver Low Voltage Soldering Iron Desoldering Tool Contact Cleaner REPLACEMENT PARTS AND DESCRIPTION 6 StW> IDENT PART NO. DESCRIPTION DISK II INTERFACE BOARD UA2 UA3 UB2 UC2 UC3 UD2 UD3 MAIN BOARD CR1 F1 S1 SP1 UA11 UA12 UB1 UB2 IC, SN74LS132N IC, Flip/Flop, 74LS174PC IC, 74LS05PC IC, Latch, N9334N IC, Shift Register, SN74LS323N IC, Timer, MC3456P IC, PROM, 31-0127-A LED, Power Fuse, AC, 2.75A Switch, Power Speaker IC, RC741N IC, Timer, NE558N IC, Tri-State Buffer, SN74LS244N IC, Transceiver, 74LS245N IDENT UB5 UB8 UC1 UC4 UC5 UC10 UC12 UD1 UE1 UE4 UE5 UE8 UE10 UE12 UE14 UF4 UF5 UF6 Thru UF13 Y1 PART NO. DESCRIPTION IC, Decoder/Mux, 74LS138PC IC, SN74S02N IC, Flip/Flop, 74F109DC IC, Microprocessor, R6502-40 IC, HD74LS10P IC, Decoder/Demux, DM74LS154N IC, Mux, SN74LS251NDS IC, Program Logic Array, HAL16R8CN ' IC, DM74LS125AN IC, Memory Management Unit, 344-001 0-B IC, Input/Output Unit, 344-0020-A IC, CD-ROM, 342-0135-B IC, EF-ROM, C19659 IC, Keyboard ROM, 342-01 32-B IC, Decoder, AY-5-3600-PRO IC, Video ROM 342-01 33-A IC, Shift Register, 74166N IC, RAM, TMS4164-15NLJ Crystal, 14.31818MHz CAJkAC Howard W. Sams & Co. &tfWTw9i* 4300 West 62nd Street, P.O. Box 7092, Indianapolis, Indiana 46206 U.S.A. The listing of any available replacement part herein does not constitute in any case a recommendation, warranty or guaranty by Howard W. Sams & Co., Inc., as to the quality and suitability of such replacement part. The numbers of these parts have been compiled Irom information furnished to Howard W. Sams & Co.. Inc., by the manufacturers of the particular type of replacement part listed. Reproduction or use, without express permission, of editorial or pictorial content, in any manner, is prohibited. No patent liability is assumed with respect to the use of the information contained herein. © 1985 Howard W. Sams & Co., Inc. 4300 West 62nd Streei. P.O. Box 7092, Indianapolis. Indiana 46206 U.S.A. Printed in U.S. of America 84CC14918 DATE 3-85 PRELIMINARY SERVICE CHECKS (Continued) SERVICE CHECKS SEE INTERCONNECTING DIAGRAM AND PHOTOS TO MATCH THE NUMBER IN THE CIRCLES WITH THOSE IN THE FOLLOWING DATA FOR SERVICE CHECKS TO BE PER- FORMED. © COMPUTER DEAD (A) If the Power LED (CR1) is not lit, disconnect the Power Supply from Connector J14 and check for 5.3V at pin 3, 12.5V at pin 4, - 11.9V at pin 5 and -5.0V at pin 6 of Connector P14. If all the voltages are missing, check AC Fuse (F1), Power Switch (S1) and the AC Line Cord (P20). (B) If the Power Supply operates normally, turn Off the Computer and remove any boards plugged in- to the seven Peripheral Slots (J1 thru J7) or the Auxiliary Connector (JO). Turn the Computer On and check its operation. If the Computer starts functioning, turn the Computer Off and plug each board back into its respective peripheral slot, one board at a time. After each board is reinstalled, turn On the Computer and check its operation. Continue this process until the defective board is found. (C) If the Computer does not function with the peripheral boards removed, listen for a beep when turning On the Computer or while pressing the CONTROL and G keys at the same time. A beep indicates the Microprocessor IC (UC4) is working and the problem may be in the video circuits. If a beep is heard, refer to the "Video" section of this Service Checks guide. If there is no beep, check for a momentary Low logic reading, then a High logic reading at pin 40 of IC UC4 while turning On the Computer. If the logic reading is incorrect, check Input/Output Unit IC (UE5) by substitution. (D) If pin 40 of Microprocessor IC (UC4) is normal, check for clock pulses at pin 37 of IC UC4 and pin 12 of IC UE1. If pulses are present at IC UE1 and missing at IC UC4, check Flip/Flop IC (UC1), Pro- gram Logic Array (UD1), and ICs UE1 and UB8 by substitution. (E) If the clock pulses are normal, check the Microprocessor IC (UC4), CD-ROM IC (UE8), EF- ROM IC (UE10) and RAM ICs (UF6 thru UF13) by substitution. (F) If the Computer is still inoperative, check Tri-State Buffer IC (UB1), Transceiver IC (UB2), Memory Management Unit IC (UE4) and Input/Output Unit IC (UE5) by substitution. (?) VIDEO (A) No video display and no beep is heard when the Computer is turned On. Refer to the "Computer Dead" section of this Service Checks guide. If a beep is heard, check the video cable going to the Monitor for good connections and possible open circuits. Also, check the Monitor by substitution. (B) Check IC UC5, Input/Output Unit IC (UE5), Video ROM IC (UF4) and Shift Register IC (UF5). (3) NO VIDEO SYNC (A) Monitor display rolls vertically and tears horizon- tally. Check the Input/Output Unit IC (UE5) by substitution. (4) GRAPHICS MODE DOES NOT WORK (A) Check Input/Output Unit IC (UE5) and Video ROM IC (UF4) by substitution. NO COLOR (A) Check the frequency of the 14.31818MHz Oscil- lator at pin 12 of IC UE1. If the Oscillator is off fre- quency, check the 14.31818MHz Crystal (Y1) by substitution. (B) If the Oscillator is on frequency, check Input/Out- put Unit IC (UE5) and IC UB8 by substitution. © © KEYBOARD (A) Keyboard is inoperative. Check the keyboard cable and connectors for good connections. (B) If the keyboard cable and connectors are good, check Memory Management Unit IC (UE4), In- put/Output Unit IC (UE5), Keyboard ROM IC (UE12) and Decoder IC (UE14) by substitution. (C) Wrong character appears on Monitor screen when a key is pressed. Check Keyboard ROM IC (UE12) and Decoder IC (UE14) by substitution. (D) Character repeats itself when a key is pressed momentarily or will not repeat when a key is held down. Check Decoder IC (UE14) by substitution. (E) A group of keys do not work. Check the keyboard cable and Connector J17A for good connections and check Decoder IC (UE14) by substitution. (F) One key does not work or is erratic. Clean the key contacts. If the key still does not work, check the solder connections on the bad key and check the key contact with an ohmmeter. NO BEEP FROM SPEAKER (A) Computer is functioning but there is no sound from the speaker when the CONTROL and G keys are pressed. Check the Speaker Connector (J 18) for good connections and check the Speaker (SP1) voice coil for a resistance of 7.6 Ohms. (B) Check Input/Output Unit IC (UE5) by substitution. II PRELIMINARY SERVICE CHECKS (Continued) (8A) (IB (no PERIPHERAL SLOTS DISK 11 INTERFACE BOARD DRIVE I \ 1M3 ~| FLIP/FLOP 20 UA2 t UB3 UB2 UC3 UC2 SHIFT REGISTER LATCH DRIVE 2 UD3 PROM i 20 ] 19 25 SERVICE CHECKS (Continued) BOARDS PLUGGED INTO PERIPHERAL SLOTS DO NOT FUNCTION (A) Check the edge connectors on the board for dirty contacts. Use a pencil eraser to clean the con- tacts if dirty. (B) Check Decoder/Mux (Multiplexer) IC (UB5), Decoder Demux (Demultiplexer) IC (UC10) and IC substitution. © JOYSTICKS OR PADDLES DO NOT FUNCTION (A) Check Connectors J8 and J15 for good connec- tions. (B) Check Timer IC (UA12), Transceiver IC (UB2), De- coder/Mux (Multiplexer) IC (UB5), Decoder/Demux (Demultiplexer) IC (UC10), Mux (Multiplexer) IC (UC12), Memory Management Unit IC (UE4) and IC UB8 by substitution. CASSETTE (A) Computer will not save a Check Input/Output Unit IC ( onto tape. ) by substitution. (B) Computer will not load a program from tape. Check Transceiver IC (UB2), Decoder/Mux (Multiplexer) IC (UB5), Mux (Multiplexer) IC (UC12), Decoder/Demux (Demultiplexer) IC (UC10), Memory Management Unit IC (UE4) and ICs UA11 and UB8 by substitution. (fj) DISK II INTERFACE BOARD (A) Disk Drive operation is erratic. Check the two Disk I Drive connectors for good connections and check the Disk II interface board edge connector for dirty contacts. Clean the edge connector with a pencil eraser if dirty. (B) Disk Drive does not turn On. Check Latch IC (UC2), Timer IC (UD2) and ICs UA2 and UB2 by substitution. (C) Will not select proper Disk Drive. Check Latch IC (UC2) and IC UA2 by substitution. (D) Read or write problems. Check Flip/Flop IC (UA3), Shift Register IC (UC3), PROM IC (UD3) and IC UA2 by substitution. (E) Does not recognize the write protect signal. Check Shift Register IC (UC3) by substitution. INTERCONNECTING DIAGRAM III PRELIMINARY SERVICE CHECKS (Continued) t MAIN BOARD IV DISK II INTERFACE BOARD V KEYBOARD 6F PRELIMINARY SERVICE CHECKS (Continued* POWER SUPPLY BOARD 2.75* (3) PH WIRIN6 VIEW 5.3V -11. BV I 3/ 5 H.31818MH2 PIN 12 ©^ 11 * \«>.ov * 12. SV f UE1 | [ UP1 | [ UC1 TR1 -5TATE BUF FER \ UB1 1 3 5 CRYSTAL PR06RAM FLIP/FLOP 60 LOGIC ARRAY 3 , ♦ ♦ ♦ ♦ ♦ • POWER JH POWER Of 2 4 6 IB) AUX CONNECTOR UB2 98 CR1 o TRANSCE I VER ( 1 0B] ® © UBS JI C'c) (id) Oe) I so 25 25 UF4 VIDEO ROM ^ -r==j ^ MEMORY UC4 J2 I 50 25 25 MI J3 SHIFT © UF5 RE6ISTER UF6 UF8 UF9 I UES 2B (SB UBS J4 UE8 CD-ROM DECODER/DEMUX ® @ E3 J6 UF10 UF11 UF12 UF19 I J UE10 © 25 X UC10 EF-ROM UE12 UC12 UA11 KEYBOARD ROM @©@® MUX □ I JIB 11 OEM NUMERIC KEY PAD KEYBOARD UA12 TIMER CAME I/O J17A SPEAKER JIB DECODER & I Tsp K SP7 »1 |T»ljl9 'X JI5 JO ® JI MODULATOR M/A JN BOiARD INTERCONNECTING DIAGRAM VI PRELIMINARY SERVICE CHECKS (Continued) PREVENTATIVE MAINTENANCE ENVIRONMENT Computers perform best in a clean, cool area that is below 80 degrees Fahrenheit and free of dust and smoke particles. Ev though home Computers are not affected by cigarette smoke as much as commercial Computers are affected, it is better v maintain a smoke-free area around the Computer. Do not block cabinet vents of any of the Computer system- Computei Monitor, Printer, or other power devices. ELECTRICAL POWER Variations in the line voltage can affect the Computer. Try to avoid these fluctuations by using an AC receptacle that is on a power line not used by appliances or other heavy current demand devices. A power-surge protector, power-line conditioner or non-interruptable power supply may be needed to cure the problem. Do not switch power On and Off frequently. KEYBOARD Liquids spilled into the Keyboard can ruin it. Immediately after a spill occurs, disconnect the Computer power plug from AC power outlet. Then, if circuitry or contacts are contaminated, disassemble the Keyboard and carefully rinse the Keyboard printed circuit board with distilled water and let it dry. Use a cotton swab to clean between the keys. Use a non-abrasive con- tact cleaner and lint-free wipers on accessible connectors and contacts. DISK DRIVES 3 Clean the read/write heads of the Disk Drives about once a month or after 100 hours usage. Use only an approved head clean- 2 5 ing kit. O T> r- r Handle carefully to preserve proper disk head alignment. A sudden bump or jolt to the Disk Drives can knock the disk head out y m of alignment. If the disk drive must be transported, place an old disk in slot and close door during transport. Store disks in their protective covers and never touch the disk surface. Observe the disk handling precautions usually found on the back of disk protective covers. PRINTERS Carefully vacuum the Printer regularly. Wipe surface areas clean using a light all-purpose cleaner. Do not oil the machine The oil will collect abrasive grit and dust. The dust will act as a blanket. This can cause components to overheat and fail. STATIC ELECTRICITY Static electricity discharge can affect the Computer. In order to minimize the possibility, use anti-static mats, sprays tools and materials, and maintain good humidity in the Computer environment. MONITOR Use an isolation transformer with any Monitor that does not come as part of the system since some Monitors use a HOT chassis (chassis connected to one side of the AC line). The face of the Monitor should never be left on for long periods of time at high brightness level except when pattern is being changed periodically. Use caution when cleaning anti-glare screens to preserve the glare-reduction feature. VII PRELIMINARY SERVICE CHECKS (Continued) GENERAL OPERATING INSTRUCTIONS POWER UP The Computer will come up in Basic mode when turned On with no Disk Drive connected. If a Disk Drive is connected the Computer will automatically boot up any bootable diskette that is Inserted into the Disk Drive. If no diskette is in the Disk Drive, press the CONTROL and RESET keys at the same time to stop the Disk Drive and put the Computer in Basic mode. SWITCHING FROM BASIC TO MONITOR MODE Type CALL-151 and press RETURN key. An asterisk will ap- pear on the Monitor screen indicating the Computer is in the Monitor mode. SWITCHING FROM MONITOR TO BASIC MODE Press the CONTROL and C keys at the same time, then press the RETURN key (any Basic program already in memory, before going to the Monitor mode, will remain in memory). Press the CONTROL and B keys at the same time, then press the RETURN key (any Basic program in memory will be lost). RESET Press the CONTROL and RESET keys at the same time to reset the Computer to Basic mode. Press the OPEN APPLE key (located on the left side of SPACE bar), CONTROL key and RESET key at the same time to reboot the system on any bootable diskette in the Disk Drive. OPERATING THE DISK SYSTEM FROM BASIC MODE (DOS3.3 OR PRODOS) Type CATALOG and press the RETURN Key to get a list of the programs which are on the diskette. Type CATALOG, D1 for Disk Drive 1 or CATALOG, D2 for Disk Drive 2 if the current disk drive is not the one desired. Type LOAD and the program name, then press the RETURN key to load a program from the diskette. Type SAVE and the program name, then press the RETURN key to save a program on the diskette. BOOTING UP THE DISK OPERATING SYSTEM (DOS) Insert a diskette containing a DOS into the Disk Drive 1 and turn On the Computer. The Computer will automatically load the DOS and come up in Basic mode if DOS3.3 is used. If PRODOS is used the Computer will come up with menu of PRODOS features on the Monitor screen. To boot from Basic mode, type PR#6 or 1N#6 and press the RETURN key. If there is no diskette in the Disk Drive, the Disk Drive will continue to run until a diskette is inserted or the CONTROL and RESET keys are pressed at the same time. DOS can also be rebooted by pressing the OPEN APPLE key (located on left side of SPACE bar), CONTROL key and RESET key at the same time. USING BLANK DISKETTES A blank diskette must be Initialized (DOS3.3) or Formatted (PRODOS) before it can be used to save data. To initialize a diskette using DOS3.3, boot the disk operating system from a diskette containing DOS3.3, remove the DOS3.3 diskette and put the blank diskette into Disk Drive 1. Type INIT HELLO and press the RETURN key. The diskette will be in- itialized when the drive stops. NOTE: Any previous informa- tion on diskette will be over written and lost when initializ- ed. If PRODOS is being used, select the PRODOS FILER (press F key) from the menu that comes up when PRODOS is booted up. Select Volume Commands (press V key) from the second menu that comes up and then select Format A Volume (press F key) from the third menu that comes up. In- sert the blank diskette into the Disk Drive and follow the in- structions on the Monitor screen to format the diskette. CASSETTE OPERATION NOTE: The following procedure will not work if PRODOS is loaded into the Computer. PRODOS does not support the Cassette input-output ports. Connect the microphone cable from the Cassette to the Cassette Out Jack on the Computer. Connect the speaker cable from the Cassette In Jack on the Computer. To save a Basic program put the Cassette in Record mode, type SAVE and press the RETURN key. The program has been saved when the second beep is heard. To load a Basic program set the tone control to the high end adjust the volume to just audible. Type LOAD and press the RETURN key. Set the Cassette to the beginning of the pro- gram and press the PLAY button on the Cassette. When se- cond beep is heard, the program has been loaded. DISASSEMBLY INSTRUCTIONS CABINET REMOVAL Remove nine screws from cabinet bottom. Lift cabinet top and keyboard from chassis and disconnect keyboard plug. MAIN BOARD REMOVAL Release six plastic locking pins and remove four screws holding main board to cabinet bottom. Disconnect speaker plug and power supply plug from main board and remove board from cabinet. POWER SUPPLY BOARD REMOVAL Remove four screws holding power supply to cabinet bot- tom and remove from cabinet. Remove ten screws, five from each side of power supply case for access to power supply board. VIII Y SERVICE CHECKS (Continued* PRELIMINARY SERVICE CK POWER SUPPLY BOARD N P14 WIRING VIEW S.9V -I1.9V I 3/ S P20 @ J S1 ^ J POWER i. 31878MHz PIN 12 ^T 1 UE1 UDI * 12.SV [^11 [ UC1 PROGRAM FLIP/FLOP L06IC ARRAY 3 , 5 AUX CONNECTOR ! 003 I TRI-STATE BUFFER ! ubi 1 © TRANSCEIVER (108 I 3 5 POWER J14 2 4 6 POWER ON CR1 o © [ UBS J1 0<0 0« Oe) 25 26 UE4 MEMORY MANAGEMENT UNIT UE5 n 3? UC4 MICRC PROCESSOR © @_ ' UC5 J> UBS J2 25 26 J3 2S 26 \ INPUT/OUTPUT UNIT UES OECOOER/OEMUX © Q © © CD-ROM 07) 25 26 J6 UE10 © J7 J (6A) © SLOTS UC10 EF-ROM DECODER/OEMUX (9B)(lOB) DISK J J INTERFACE BOARD DRIVE 1 20 UA3 FLIP/FLOP [ UB3 ran ,i=j. E UB2 SHIFT REGISTER LATCH ] [ UD3 UD2 timer" DRIVE 2 2 20 I I I 19 UE12 UC12 KEYBOARD ROM g)@©@ MUX © UA11 □ M ® JOYSTICK IN J9 "□CASSETTE JN □ CASSETTE OUT 1 J16 11 UEH NUMERIC KEY PAD KEYBOARD [Sflli UA12 TIMER GAME I/O -J-i JM (») — VIDEO W — r— ' OUTPUT DECODER J13 © MODULATOR J12 □ MAIN BOARD INTERCONNECTING DIAGRAM ERVICE CHECKS (Continued) » * PRELIMINARY SERVICE CHf COMPUTERFACTS' APPLE MODEL He SAFETY PRECAUTIONS PRELIMINARY SERVICE CHECKS See page 30. ENCLOSED — Block Diagram Disassembly Instructions General Operating Instructions GridTrace Location Guide Disk II Interface Board Main Board IC Pinouts & Terminal Guides . . Line Definitions Logic Chart Parts List _ 21 6 6 22 24 5,32 31 . .27,28,29 .16 thru 20 Photos Disk II Interface Board Main Board Power Supply Board . . Safety Precautions Schematics Disk II Interface Board Keyboard Main Board Power Supply Schematic Notes Dub Page 15,22 .11,12,25,26 . . .13,14,23 30 Troubleshooting 4,33 2 . .2,35,36,37 3,34 30 ...7thru10 CAA/aC Howard W. Sams & 4300 West 62nd Street, P.( The listing of any available replacement part herein does not constitute in any case a recommendation, warranty or 9 uaranty by Howard W. Sams S Co., Inc., as to the quality and suitability of such replacement part. The numbers of these parts have been compiled from information furnished to Howard W. Sams 8 Co., Inc., by the manufacturers of the particular type of replacement part listed. Co. ). Box 7092, Indianapolis, Indiana 46206 U.S.A. Reproduction or use, without express permission, of editorial or pictorial content, in any manner, is prohibited. No patent liability is assumed with respect to the use of the information contained herein. © 1985 Howard w. Sams & Co., Inc. 4300 West 62nd Street, P.O. Bo, 7092. Indianapolis, Indiana 46206 U.S.A. Printed in U.S. of America. 84CC14918 DATE 3-85 KEYBOARD SI 4 S42 556 539 I DELETE RETURN \ V S62 I S63 ] me | 513 ~544 S31 SI 6 51 I Z A TAB ESC S45 S33 517 X D 1 U » - f ' S46 C 532 S 51 8 V 536 H S3 2 S47 V Ul 548 B SI 9 E 534 F J178 V 4 520 R 4 78 S49 N S35 G 522 Y ■JLHI t 526 P S60 S58 SPACE 527] 511 ] 555 550 N I 537 J Xi 78 S21 T ? 8 6 4—3 S51 S38 K 523 U S61 JL S41 521 I J 540 Li£L 78 ... »" S6 , S J T J17B f¥ 7 524 I SS3 7 / 3 J17B f 17S S39 L S25 510 f 2 US J17B J17BT J J178 18 J17B J178 16 J178 4? 19 J17B J17B 515 RESET S30 543 S54 17 CONTROL L SHIFT R SHIFT f v — V J178 J17B 1 1 J 1 78 ~S57 553 tS~ SOLID APPLE OPEN APPLE CAPS LOCK J17fl =4— W Rl J178 5 * 5 J17B^ 7 J17fl : J17B^3iR1 J17B^ 5 J17BY 7 J '' 7e ^ > S.OV J17A -<<— TO - J17A J17A J17A Y3 J17A Y4 ■ J17A it J1 7A Y6- Y7- J17A t Y8- J17, Y9- J17A X0- 18 X2- J17A 20 X4- 21 J17A -<f-xs X8- X7 j r« is 26 J17, J17A J17A -«— YS 10 — sTFr CNTL "«-X1 — 24 -5HFT — J17A -4e-CNTL — I • Y0- Y1 - Y2- • Y3- Y4 - Y5- ■ Y6- Y7- Y8- ■ Y9- ■X0- •X1 - • X2- ■ X3- ■ X4 - ■ xs ■ -55- L T5" L -57 ^0 p ~5? p p 37 P p X6- X7- 33 HC2) "25 rid) NUMERIC PAD JOYSTICK Jl6 4- YO J16 1 < Y1 2 J16 <- Y2 J16 5 < Y3 3 J16 <r~ Y4 J16 4 < YS 6 J16 4-X4 jib a < X5 11 J16 4- X6 J16 10 < X7 8 J16 • <T NC f J \ PDLO - 5 J | PDL1 - 8 J | PDL2- 4 J | POL 3 ■ 9 J | SW2 • 6 - SW2 J17A 11 SW1/CAPL SWO/OAPL CAPLCOT 1 SW^OAPL — J <SW1/CAPL- 1 2 ^-js.ovco 'part of I e RP2 1000 - 1 T8 1000J | J ; i S.OV X6 ■PDLO C37 R23 100 -f-feoV^— $ , . 100 * ■ PDL1 --t-H6lHvvv— ^ •PDL2--t--l62} C35-T ■ P0L3 —J— |B3| — wv ^ OV C34T .0221 C07X- s.ov s.ov OV s.ov NE558N S.OV UA12 OV TIMER H T H H TJ 4.1V SEE SCHEWTJC NOTi TAKING VOLTAGES, WA AND LOGIC PROBE RS s ; I .(A a photofact sta ndard notation schematic with wihuhhB ® Howard W. 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If a Disk Drive is connected the Computer will automatically boot up any bootable diskette that is inserted into the Disk Drive. If no diskette is in the Disk Drive, press the CONTROL and RESET keys at the same time to stop the Disk Drive and put the Computer in Basic mode. SWITCHING FROM BASIC TO MONITOR MODE Type CALL-151 and press RETURN key. An asterisk will ap- pear on the Monitor screen indicating the Computer is in the Monitor mode. SWITCHING FROM MONITOR TO BASIC MODE Press the CONTROL and C keys at the same time, then press the RETURN key (any Basic program already in memory, before going to the Monitor mode, will remain in memory). Press the CONTROL and B keys at the same time, then press the RETURN key (any Basic program in memory will be lost). RESET Press the CONTROL and RESET keys at the same time to reset the Computer to Basic mode. Press the OPEN APPLE key (located on the left side of SPACE bar), CONTROL key and RESET key at the same time to reboot the system on any bootable diskette in the Disk Drive. OPERATING THE DISK SYSTEM FROM BASIC MODE (DOS3.3 OR PRODOS) Type CATALOG and press the RETURN Key to get a list of the programs which are on the diskette. Type CATALOG, D1 for Disk Drive 1 or CATALOG, D2 for Disk Drive 2 if the current disk drive is not the one desired. Type LOAD and the program name, then press the RETURN key to load a program from the diskette. Type SAVE and the program name, then press the RETURN key to save a program on the diskette. BOOTING UP THE DISK OPERATING SYSTEM (DOS) Insert a diskette containing a DOS into the Disk Drive 1 and turn On the Computer. The Computer will automatically load the DOS and come up in Basic mode if DOS3.3 is used. If PRODOS is used the Computer will come up with menu of PRODOS features on the Monitor screen. To boot from Basic mode, type PR#6 or 1N#6 and press the RETURN key. If there is no diskette in the Disk Drive, the Disk Drive will continue to run until a diskette is inserted or the CONTROL and RESET keys are pressed at the same time. DOS can also be rebooted by pressing the OPEN APPLE key (located on left side of SPACE bar), CONTROL key and RESET key at the same time. USING BLANK DISKETTES A blank diskette must be Initialized (DOS3.3) or Formatted (PRODOS) before it can be used to save data. To initialize a diskette using DOS3.3, boot the disk operating system from a diskette containing DOS3.3, remove the DOS3.3 diskette and put the blank diskette into Disk Drive 1. Type INIT HELLO and press the RETURN key. The diskette will be in- itialized when the drive stops. NOTE: Any previous informa- tion on diskette will be over written and lost when initializ- ed. If PRODOS is being used, select the PRODOS FILER (press F key) from the menu that comes up when PRODOS is booted up. Select Volume Commands (press V key) from the second menu that comes up and then select Format A Volume (press F key) from the third menu that comes up. In- sert the blank diskette into the Disk Drive and follow the in- structions on the Monitor screen to format the diskette. CASSETTE OPERATION NOTE: The following procedure will not work if PRODOS is loaded into the Computer. PRODOS does not support the Cassette input-output ports. Connect the microphone cable from the Cassette to the Cassette Out Jack on the Computer. Connect the speaker cable from the Cassette In Jack on the Computer. To save a Basic program put the Cassette in Record mode, type SAVE and press the RETURN key. The program has been saved when the second beep is heard. To load a Basic program set the tone control to the high end adjust the volume to just audible. Type LOAD and press the RETURN key. Set the Cassette to the beginning of the pro- gram and press the PLAY button on the Cassette. When se- cond beep is heard, the program has been loaded. DISASSEMBLY INSTRUCTIONS CABINET REMOVAL Remove nine screws from cabinet bottom. Lift cabinet top and keyboard from chassis and disconnect keyboard plug. MAIN BOARD REMOVAL Release six plastic locking pins and remove four screws holding main board to cabinet bottom. Disconnect speaker plug and power supply plug from main board and remove board from cabinet. POWER SUPPLY BOARD REMOVAL Remove four screws holding power supply to cabinet bot- tom and remove from cabinet. Remove ten screws, five from each side of power supply case for access to power supply board. 6 TROUBLESHOOTING SELF TEST The Computer has a self test that disables any peripheral boards that are plugged into the main board and tests all programmable memory. To run the self test hold down the CONTROL and SOLID APPLE (located on the right side of space bar) keys and press the RESET key. The Monitor screen will turn white, then black, then white again, then black again and come up with the message "KERNAL OK" if no problems are found. An error message will be displayed on the Monitor screen if a problem is found. COMPUTER DEAD NOTE: Turn Off the Computer before inserting or removing boards from the peripheral slots. No display on the Monitor screen when the Computer is turned On. Check the Power LED (CR1). If LED CR1 is not lit, disconnect the Power Supply Connector (J14) and check for 5.0V at pin 3, 11.7V at pin 4, - 1 1.9V at pin 5 and - 5V at pin 6 of Connector J14. If the voltages are incorrect, refer to the "Power Supply" section of this Troubleshooting guide. If the power supply checks normal, remove all the boards plugged into the Auxiliary Connector Slot (JO) or the seven Peripheral Slots (J 1 thru J7) and check the Computer opera- tion. If the Computer starts functioning normally after removal of peripheral boards, turn Off the Computer and plug the boards into the peripheral slots one at a time. Re- check the operation until the defective board is found. If the Computer does not function with all the peripheral boards removed from the slots, listen for a beep from the in- ternal speaker when the Computer is turned On or when the CONTROL and G keys are pressed at the same time. If there is no beep, seethe "Microprocessor (CPU) Operation" section of this Troubleshooting guide. If there is a beep, check the cable from the Computer to the Monitor for good connections. If the cable checks normal, refer to the "Video Display" section of this Troubleshooting guide. POWER SUPPLY NOTE: Use an isolation transformer when troubleshooting the power supply. Check the AC Fuse (F1) and if Fuse F1 is open, check AC Line Choke Coil (T1) for a possible short. If Coil T1 is good, check associated components for shorts and check from each lead of Coil T1 to the chassis for shorts. Check for a possible shorted Driver Transistor (Q2). If Fuse F1 is not open, apply AC power and check for 120VAC between Connector L and N. If 120VAC is missing, check the Power Switch (S1), Coil T1 and the AC Power cord Connector (P21). If 120VAC is present, check for 120VAC across the AC inputs of Diode DB1. If 120VAC is missing, check Coil T1 and Thermistor R1. If 120VAC is present, check for 330V between the negative and positive output of Diode DB1 and if 330V is missing, replace Diode DB1. If 330V is present, check the waveform at the base of the Oscillator Transistor (Q1). If Transistor Q1 is not oscillating, check the voltages and components associated with the Regulator Transistor (Q3), Regulator IC (IC1), Transistor Q1 and Driver Transistor (Q2). Also check the windings on Transformers T2 and T3 for continuity. If the Transistor Q1 is oscillating properly, check the voltages at pins 3, 4, 5 and 6 of Connector J14. If 5.0V at pin 3 of Connector J 14 is missing, check Diodes D7 and D8, Coil L5 and Capacitors C13 and C14. Also check the Transformer T2 windings between pin 11 and pin 12 and pin 13 and pin 14 of Transformer T2. If 11.7V at pin 4 of Connector J14 is missing, check Diode D6, Coil L6, Electrolytics C12 and C20 and winding between pin 15 to pin 16 of Transformer T2 and check Shutdown Transistor (Q4) and SCR SCR1. If -5V at pin 6 of Connector J14 is missing, check Diode D9, Coil L8, Electrolytics C15 and C22 and the winding be- tween pin 7 and pin 8 of Transformer T2. If the - 11.9V at pin 5 of Connector J14 is missing, check Diode D10, Coil L7, Electrolytics C16 and C21 and the wind- ing between pin 9 and pin 10 of Transformer T2. MICROPROCESSOR (CPU) OPERATION o If the Computer is dead and the power supply is normal, ("J check the logic reading on pin 40 of the Microprocessor _ k (CPU) IC (UC4) when Computer is turned On. The logic q reading will be Low for about .1 second then change to High. It should also read Low as long as the CONTROL and RESET keys are held down. If the logic reading is incorrect, check Input/Output Unit IC (UE5) by substitution. 2 O > If the reset circuit is working, check the 1MHz clock wave- m "O form at pin 37 of IC UC4. If the waveform is missing, check PT jZ the waveform at pin 14 of Program Logic Array IC (UD1). If jjf the wavform is present at pin 5 of IC UB8 and pin 6 of IC UB8 logic reading is Low, check IC UB8 by substitution. If the waveform is missing at pin 5 of IC UB8, refer to the "Crystal Oscillator and Dividers" section of this Troubleshooting guide. If the clock waveform at pin 37 of IC UC4 is normal, check for clock pulses at pins 3 and 39 of IC UC4. If the pulses are missing, check IC UC4 by substitution. If the pulses are present, check for a High logic reading on pins 2, 4 and 6 of IC UC4. If any of the logic readings are Low, check the part of Resistor Network RP1 connected to the pin with the Low logic reading. Also check for a possible short to ground and check IC UC4 by substitution. To check the address li nes, turn Off the Computer , remnye '/jp£££ any peripheral boards plug ged into the main board, connect a jumper fromj in 2 of IC UB8 to jrnnnn; turn On the Com- - M . puter and check for a Low logic reading on pins 9 thru 20 . . and 22 thru 25 of IC UC4. If any of the pins do not read cor- 5l*Tfc rectly, check IC UC4 and the Tri-State Buffer ICs (UB1 or UB3) connected to the bad pin, by substitution. If the ad- dress lines on IC UC4 read logic Low, check the buffered ad- dress lines, pins 3, 5, 7, 9, 12, 14, 16 and 18 of ICs UB1 or UB3 for a logic Open (No lights On). If any of the buffered address lines read a logic High or Low check by substitu- tion any IC associated with the defective line. If no problems have been found at IC UC4, check CD-ROM IC (UE8) and EF-ROM IC (UE10), Memory Management Unit IC (UE4) and RAM ICs (UF6 thru UF13) by substitution fal«l CHIP 9*P H»»b& At "I cVBrtPrflt D(SPL«n 7 TROUBLESHOOTING (Continued) CRYSTAL OSCILLATOR AND DIVIDERS Check the oscillator frequency (14. 31818MHz) at pin 12 of IC UE1. If the oscillator is off frequency, check 14.31818MHz Crystal (Y1). If the oscillator is not working, check the voltages and components associated with Output Tran- sistor (Q4) and Oscillator Transistor (Q6). If the oscillator is working, check the waveform at pin 11 of IC UE1. If the waveform is missing and pin 13 of IC UE1 logic reading is Low, check IC UE1 by substitution. If the waveform is good, at pin 1 1 of IC UE1, check for a frequency of 3.5795MHz at pin 10 of Flip/Flop IC (UC1). If the signal is missing or the frequency is incorrect, check IC UC1 by substitution. If the frequency is correct at pin 10 of IC UC1, check the waveforms at pins 14 thru 16 and 19 of Program Logic Array IC (UD1) and pins 6 and 15 of Shift Register IC (UF5). If any of the waveforms are missing, check IC UD1 by substitution. KEYBOARD If Computer comes up properly but the keyboard is dead or has no response when any key is pressed, check Connector J14 and the cable from the keyboard to the main board for good connections. If the cable and connectors are normal, check for -11.9V at pin 27 of the Decoder IC (UE14). If - 11.9V is missing, refer to the "Power Supply" section of this Troubleshooting guide. If - 1 1.9V is present, check the waveform at pin 1 of IC UE14. If the waveform is missing, check Capacitor C70, Resistor R32 and check IC UE14 by substitution. If the waveform is present at pin 1 of IC UE14, check the waveforms on pins 16 thru 26 and 33 thru 40 of IC UE14. The waveforms on pins 17 thru 26 should look similar to the waveform shown in Figure 1 and the waveforms on pins 33 thru 40 should look similar to Figure 2. Figure 1 Figure 2 3.8V 50/<s -8V DC Reference .3V 50/<s -8V DC Reference If any waveform is missing, check IC UE14 by substitution. If the waveforms are present, check the logic readings on pins 5 and 16 of IC UE14. Pin 5 logic reading should be High and pin 16 should read a Pulse when any key is pressed ex- cept the CONTROL, SHIFT, CAPS LOCK, RESET and APPLE Keys. If either reading is incorrect, check IC UE14 by substitution. If the readings are correct, check waveform at pin 18 of the Memory Management Unit IC (UE4). If the waveform is missing at pin 18, check the IC UE4 by substitu- tion. If the waveform is present at pin 18 of IC UE4, check IC UE12 and Input/Output Unit IC (UE5) by substitution. If only one key does not work, check the solder connection on the defective key and check the key for continuity when the key is pressed. If only one key is erratic, clean the contacts of the defective key. If a wrong character appears on the Monitor screen when a key is pressed, check ICs UE12 and UE14 by substitution. If a character appears more than once on the Monitor screen when a key is pressed momentarily, check Capacitor C71 and check IC UE14 by substitution. If a character does not repeat, when a key is held down, check Capacitor C70 and check IC UE14 by substitution. If any one group of keys do not work, check the keyboard cable and Connector J17A and J17B for good connection and also check IC UE14 by substitution. VIDEO DISPLAY No video on the Monitor screen, check the Video Output Jack (J11) and the cable connecting the Computer to the Monitor for good connections. If the cable and connectors are good, check for a 2.5V pp video waveform at the base of Mixer Transistor (Q1). If the waveform is present, check the voltages and components associated with Transistor Q1 and Video Output Transistor (Q2). If the video portion of the waveform is missing, horizontal and vertical sync pulses ap- pear, check for pulses at pin 3 of IC UC5. If pulses are pres- ent and pin 4 of IC UC5 logic reading is High, check Resistor R7 and check IC UC5 by substitution. If pulses are missing at pin 4 of IC UC5, check Shift Register IC (UF5), Video ROM IC (UF4) and Input/Output Unit IC (UE5) by substitution. If a graphics function (low resolution) or flash and inverse video functions do not work, check ICs UE5 and UF4 by substitution. If the cursor is defective or there is no cursor, check EF- ROM IC (UE10) and IC UF4 by substitution. VIDEO SYNC Monitor has no horizontal or vertical sync. Check the In- put/Output Unit IC (UE5) by substitution and check Capacitor C25 and Resistors R5 and R10. COLOR No color, type and run the following Basic program and check for pulses at pins 11 and 13 of IC UB8. 1 GR: COLOR = 4: HLIN 0.39 AT 20 If pulses are missing at pin 11, check Input/Output Unit IC (UE5) by substitution. If pulses are missing from pin 13 of IC UB8, check Capacitor C32, Coil L3 and check the fre- quency of 14.31818MHz Crystal (Y1) at pin 12 of IC UE1. If Crystal Y1 is off frequency, check Crystal Y1 by substitu- tion. If pulses are missing from pin 13 of IC UB8, check IC UB8 by substitution. If colors are incorrect, the above program should produce a green horizontal bar on the Monitor screen. Check the fre- quency of Crystal Y1 at pin 12 of IC UE1. If Crystal Y1 is off frequency, check Crystal Y1 by substitution. If Crystal Y1 is normal, check ICs UD1 and UE5 by substitution. TROUBLESHOOTING (Continued) INTERNAL SPEAKER If there is no sound from the internal speaker, check the Speaker (SP1). If the speaker checks normal, type and run the following Basic progam, 1 PRINT CHRS(7): GOTO 1 Check for pulses at pin 8 of the Input/Output Unit IC (UE5). If pulses are missing, check IC UE5 by substitution. If pulses are present, check the voltages and components associated with Amp Transistor (Q5). CASSETTE Computer will not load a program from the tape but game paddles and switches are working normally. Check the voltages and components associated with IC UA11 and check Mux (Multiplexer) IC (UC12) by substitution. Computer will not load and there are problems with the game paddles and switches. See "Game Paddles Do Not Function" or "Game Switches (Joysticks) Do Not Function" sections of this Troubleshooting guide. Computer will not save a program on tape. Check Resistors R6 and R9 and check Input/Output Unit IC (UE5) by substitu- tion. PERIPHERAL SLOTS If a board which is plugged into one of the seven Peripheral Slots (J1 thru J7) does not work, check that peripheral slot for damaged or dirty pins or for possible broken solder joints. Use a pencil eraser to clean the contacts of the board if they appear dirty. See that the peripheral slots pins 1, 20 and 41 that may be used to select the board, are functioning. To do this, run the following Basic program and check for pulses at pins 1, 20 and 41 of the peripheral slots. FOR X = NEXT X FOR X = NEXT X GOTO 1 16255 TO - 16127 STEP 16: Y = PEEK (X): 16128 TO - 14336 STEP 256: Y : PEEK (X): If pulses are missing at pin 1 of any peripheral slot, check Decoder/Mux (Multiplexer) IC (UB5) by substitution. If pulses are missing at pin 20 of any peripheral slot, check IC UC5 by substitution. If pulses are missing at pin 41 of any peripheral slot, check Decoder/Demux (Demultiplexer) IC (UC10) by substitution. GAME PADDLES DO NOT FUNCTION Type and run the following Basic program to check the operation of the game paddle circuits. The program scans all four paddles and displays the paddle number (0 thru 3) on the Monitor screen along with a number that is read from each paddle. The number read from each paddle should vary between and 255 as that paddle is varied from MINIMUM to Maximum positions. If paddles are not available, a 100K potentiometer can be used by connecting one end of the potentiometer to 5.0V (pin 1 of Connector J15) and the center tap to one of the paddle in- puts (pins 6, 7, 10 and 11 of J15). Check Connectors J8 or J15 for good connections. If none of the paddle inputs function, check for pulses at pin 3 of Timer IC (UA12) and pin 7 of Mux (Multiplexer) IC (UC12) while the above program is running. If pulses are missing, check ICs UB5 and UC10 and Memory Management Unit IC (UE4) by substitution. If pulses are present at pins 3 of IC UA12 and pin 7 of IC UC12, check for pulses at pins 1 and 19 of Transceiver IC (UB2) while the above program is running. If pulses are missing at pin 1 of IC UB2, check IC UE4 by substitution. If pulses are missing at pin 19 of IC UB2, check IC UB8 by substitution and check Capacitors C34, C35, C37 and C40 and Resistors R21 thru R24. GAME SWITCHES (JOYSTICK) DO NOT FUNCTION Q Game paddles function but game switches do not function, o check the switch input pins, pins 2, 3 and 4 of Connector ■* J15 and pins 1, 6 and 7 of Connector J8, for good connec- O tions. If the connections are good, check IC UC12 by substitution. 10 FOR Y = TO 3 20Z = PDL(Y) 30 PRINT "PADDLE"; Y, Z 40 NEXT Y 50 PRINT 60 FOR T=1 TO 500: NEXT T 70 GOTO 10 The following Basic program can be used to check the operation of the switch input circuit. 10Z = 2 20 PRINT "SOCKET", "X" 30 FOR Y = - 16287 TO - 16285 40 X = PEEK (Y) 50 PRINT "J 15 PIN"; Z, X 60 Z = Z+ 1: NEXT Y 70 FOR T= 1 TO 500: NEXT T 80 PRINT: GOTO 10 The program repeatedly displays on the Monitor screen the input pin number of Connector J15 being checked with a number X associated with the pin number given. The number X should be 127 or less if Connector J15 pin number shown on the Monitor screen is connected to ground (pin 8 of J15) and 128 or more if the pin is connected to 5.0V (pin 1 of J 15). CHECKING GAME I/O STROBE SIGNAL Type and run the following Basic program and check for pulses at pin 5 of Connector J15. If pulses are missing, check Decoder/Mux (Multiplexer) IC (UB5), Decoder/Demux (Demultiplexer) IC (UC10), Memory Management Unit IC (UE4) by substitution. 3 O > a -o m t> <D ST*feTuP PPOBCtrMS 1 X = PEEK (- 16320): GOTO 1 i 9 TROUBLESHOOTING (Continued) DISK II INTERFACE BOARD If the disk II interface board is not working, check the Disk Drive Connectors (J1 and J2) and Edge Connector J6 for good connections. If the Edge Connector J6 contacts ap- pear dirty, use a pencil eraser to clean them. If the connectors are normal, check the logic reading at pin 5 of Timer IC (UD2) while turning On the Computer. The logic reading should be High for about .1 second then change to Low. If the reading is incorrect, check Capacitor C1, Resistor R4 and check IC UD2 by substitution. If IC UD2 circuitry checks normal, turn Off the Computer. Disconnect the Disk Drives from the disk II interface board and plug the disk II interface board into Peripheral Slot (J6). Turn On the Computer, press the CONTROL and RESET keys at the same time to get the Computer into the Basic mode. Type and run the following Basic program. All tests made from this point should be made while the program is running. Press the CONTROL and RESET keys at the same time to stop the program. DISK II INTERFACE TEST PROGRAM 10X = PEEK(-16151) 20 X = PEEK (- 16149) 30 X = PEEK (- 16148) 40 X = PEEK (-16146) 50 X = PEEK (-16145) 60 X = PEEK (-16147) 70 FOR Y = - 16153 TO 80 X = PEEK (Y) 90 NEXT Y 100 X = PEEK (-■ 16160 STEP - 1 (- 14608): GOTO 20 ^heck for a High logic reading at pin 9 of IC UD2. If the logic reading is not High, check for a High logic reading at pin 9 of Latch IC (UC2). If the logic reading is not High at IC UC2, check IC UC2 by substitution. If the logic reading is High at IC UC2 check for a Low logic reading at pin 6 of IC UB2. If the logic reading is not Low at IC UB2, check IC UB2 by substitution. If the logic reading is Low at IC UB2, check IC UD2 by substitution. If the logic reading is High at pin 9 of IC UD2, check for 4.9V at pin 16 of Flip/Flop IC (UA3). If 4.9V is missing, check for a Low logic reading at pin 10 of IC UB2. If the reading is not Low at IC UB2, check IC UB2 by substitution. If the reading is Low at IC UB2, check Resistor R6 and R7 and Switch Transistor (Q3). If 4.9V is present at pin 16 of IC UA3, check for pulses at pin 20 of PROM IC (UD3). If pulses are missing, check Driver Transistor (Q1) and Switch Transistor (Q2) and Resistors R1 and R2. If pulses are present at pin 20 of IC UD3, check the wave- form at pin 3 of IC UA2. If the waveform is missing, check IC UA2 by substitution. Check the Head Position Motor Outputs (pins 4, 5, 6 and 7 of IC UC2) by checking for the waveform shown in Figure 3 at pins 4, 5, 6 and 7 of IC UC2. If any of the waveforms are incorrect, check IC UC2 by substitution. I 0V DC Reference The Disk II Interface Test Program enables Disk Drive 2, pin 6 of IC UA2 logic reading should be Low and pin 10 of IC UC2 logic reading should be High. To enable Disk Drive 1, change the number - 16149 in line 20 to - 16150 and run the program. Pin 8 of IC UA2 and pin 10 of IC UC2 logic reading should be Low with Disk Drive 1 enabled. If the logic reading at pin 10 of IC UC2 is not Low, check IC UC2 by substitution. If the reading at pin 6 or pin 8 of IC UA2 is not Low, check ICs UA2, UD2 and UB2 by substitution. To check the write and read circuits, turn Off the Computer, connect two Disk Drives to the disk II interface board and plug the board into Peripheral Slot (J6). Type and run the Disk II Interface Test Program. Check for pulses on pin 4 of IC UB2 and at pins 11 and 12 of IC UC2. If pulses are missing at pin 4 of IC UB2 and present at pin 12 of IC UC2, check IC UB2 by substitution. If pulses are missing at pins 11 or 12 of IC UC2, check IC UC2 by substitution. If pulses are present at pins 11 and 12 of IC UC2 and the disk II interface board still has write problems, check A3 and PROM IC (UB3) by substitution. If the disk II interface board has read problems, check for pulses at pins 10 and 1 i of IC UA3. If pulses are missing at pins 10 or 11 of IC UA3, check IC UA3 by substitution. If pulses are present at pins 10 and 11 of IC UA3, check for pulses at pins 12 and 11 of IC UA2. If pulses are missing at pin 12 of IC UA2, check IC UB2 by substitution. If pulses are present at pin 12 and missing from pin 11 of IC UA2, check IC UA2 by substitution. If pulses are present at pin 11 of IC UA2, check IC UB3 and Shift Register IC (UC3) by substitu- tion. If the disk II interface board can not detect the Write Protect signal, pin 11 of IC UC3, when a write protected diskette is being used, check IC UC3 by substitution. 10 A Howard W. Sam$ NI NIIW Ph oto MAIN BOARD PIN 1 S PARTS LIST AND DESCRIPTION When ordering parts, state Model, Part Number, and Description SEMICONDUCTORS (Select replacement for best results) MFGR. PART No. DISK II INTERFACE BOARD 01 02,3 UA2 UA3 UB2 UB3 UC2 UC3 UD2 UD3 2N3906 NS0U51 MPSU51 SN74LS132N 74LS1 74PC 74LS05PC 341-01 28-A 6309 P6A N9334N SN74LS323N MC3456P 556 341-01 27-A P5A MAIN BOARD 91 02 04 05 06 UA1 1 UA12 UB1 UB2 UB3 UB5 UBS UC1 UC4 ^POyuo 2N3904 f*>S4258 MPSA13 NPS4258 2N4258 RC741N MM741 NE558N SN74LS244N 74LS245N SN74LS244N 74LS138PC SN74S02N 74F109DC SI 09 R6502-40 6502B CM <W>R &Uf C-Oia. AAA. farti?A Deficit /uvuaX REPLACEMENT DATA GENERAL tLtOTRIC PART No. NEW-TONE NTE PART No. PHILIPS ECG PART No. RPA PART No. WORKMAN PART No. ZENITH PART No. GE-82 GE-253 GE-218 74LS132 74LS174 NTE159 NTE211 NTE189 NTE74LS132 NTE74LS174 ECG1 59 ECG211 ECG189 ECG74LS132 ECG74LS174 SK3466/159 SK3203/21 1 SK3200/189 SK74LS174 WEP62/159 WEP7 59/21 1 WEP857/189 121-29003 121-Z9056 121-C9053 HE-44 3-792 HE-443-879 74LS05 IN 1 t / s-LoUD C^O"7 A 1 CAE tLb/4Lb05 SK74LS05 HE-44 3-8 18 NTE978 IN 1 tL? 1 o ECG978 ECG978 SK3689/978 SK3689/978 221-Z9152 221-Z9152 GE-123AP NTE1 59 NTE123AP ECG1 59 ECG123AP SK3466/159 SK3854/123AP WEP62/159 WEP736/123A 121-Z9003 121-Z9000A GE-64 NTE 172 ECG1 72 SK3 156/1 72A WEP971/172 121-Z9024 GE-82 NTE 1 59 ECG159 SK3466/159 WEP62/159 121-Z9003 NTE941M NTE941M NTE926 ECG941M ECG941M ECG926 SK3552/941M SK35 52/94 1M WEP933/941M WEP933/941M HE-442-22 HE-44 2-2 2 74LS244 74LS245 74LS244 74LS138 74LS02 NITF74I <^?44 NTE74LS245 NTE74LS244 NTE74LS138 NTE74LS02 NTE6502 NTE6502 P CO, 7 A 1 Q.OAA ECG74LS245 ECG74LS244 ECG74LS138 ECG74LS02 ECG6502 ECG6502 o!\ /4LS244 SK74LS245 SK74LS244 SK74LS138 SK74LS02 HE-44 3- 791 HE-443-885 HE-44 3- 791 HE-44>877 HE-443-779 p2o«5 311- **M z£<t PARTS LIST AND DESCRIPTION (Continued) When ordering parts, state Model, Part Number, and Description SEMICONDUCTORS (Select replacement for best results) ITEM No. UC5 UC10 UC12 UD1 UD3 UE1 UE4 UE5 TYPE No. HD74LS10P DM74LS154N SN74LS251 NDS HAL16R8CN 74LS374N DM74LS1 25AN 344-0010-B 344-0020-A UE8 342-01 35-B 2365 2764 UE10 C19659 2365 2764 UE12 342-01 32-B 2716 UE14 AY-5-3600-PRO AY3600931PR0 UF4 342-01 33-A 2732 UF5 74166N LS166 UF6 Thru TMS4164-15NLJ UF13 6664 POWER SUPPLY BOARD D1 D2,3 D4,5 D6 Thru D8 D9 D10 D11 D12 RGP1 OA RGP1 0J 1 N4606 RGP15B RGP1 OB 1 N4606 RGP15B MFGR. PART No. KM*. 341-0170-AC1) HM- MUM Ik co 3h2-«>ij6 6f 3H2.-cx3S| 342-0134-BC1) PF-CjdW tltk CP 3H Z-e»M PR0-050C1) m®**** DRAM REPLACEMENT DATA GENERAL ELECTRIC PART No. 74LS10 74LS374 74LS125A 74166 74LS166 GE-511 6E-51 1 GE-300 GE-511 GE-51 1 GE-300 GE-51 1 NEW-TONE NTE PART No. NTE74LS10 NTE74LS251 NTE74LS374 NTE74LS125A ECG74LS10 ECG74LS251 ECG74LS374 ECG74LS1 25A >2 >52 NTE177 NTE552 NTE552 NTE177 NTE552 PHILIPS ECG PART No. ECG74166 ECG74LS166 ECG2 164 ECG6664 ECG552 ECG552 ECG1 77 ECG552 ECG552 ECG177 ECG552 RCA PART No. SK74LS10 SK74LS125A SK74166 i SK5014 SK3318A SK9091/177 SK5014 SK9000/552 SK9091/177 SK5014 an naaoiAj 31ddV 0LOO WORKMAN PART No. WEP1 72/506 WEP 172/506 WEP1062/177 WEP1 72/506 WEP1 72/506 WEP1 062/1 77 WEP1 72/506 ZENITH PART No. HE-443-797 HE-443-863 HE-443-81 1 HE-44 3-892 103-287 103-287 103-131 103-287 103-287 103-131 103-287 PARTS LIST AND DESCRIPTION (Continued) When ordering parts, state Model, Part Number, and Description SEMICONDUCTORS (Select replacement for best results) ITEM No. TYPE No. MFGR. PART No. REPLACEMENT DATA GENERAL ELECTRIC PART No. NEW-TONE NTE PART No. PHILIPS ECG PART No. RCA PART No. WORKMAN PART No. ZENITH PART No. DBl IC1 01 02 03,4 KBP08 T18231 2SD467B GEBR-1000 GE-243* NTE170 NTE85 ECG1 70 ECG85 SK3649/170 SK3449/297 WEP1 056/1 70 WEP59/128* 212-Z9002 121-792* 2SB621R GE-48 NTE294 ECG294 SK384 1/294 WEP916/294 121-Z9067 SCR1 Z1 2N6395 A211 2N6395 GEZD-1 1 NTE5552 NTE5020A ECG5552 ECG5020A SK3574 SK1 1 A/5020A WEP1 421/5020 103-279-20 (1 ) Number on unit. WIRING DATA Shielded Hook-up Wire Use BEL0EN No. 8401 or 8421 (Single-Conductor) 8208 (Two-Conductor) General-use Unshielded Hook-up Wire Use BELDEN No. 8529 (Solid) Available in 13 Colors 8522 (Stranded) Available in 13 Colors PARTS LIST AND DESCRIPTION (Continued) When ordering parts, state Model, Part Number, and Description CAPACITORS Item numbers not listed are normally available at local distributors. ITEM No. RATING MFGR. PART No. MAIN E C70 OARD 47 N470 50V 5% ITEM No. P ATINO MFGR. PART No. POWEF CI C3 C4 SUPPLY BOARD .1 125VAC .0022 400VAC .0022 400VAC L RESISTORS (Power and Special) ITEM No. RATING REPLACEMENT DATA MFGR. PART No. NEW-TONE PART No. WORKMAN PART No. MAIN BOARD RP1 RP2 RP3 Res I stor Network ( 1 ) Resistor Network (2) Resistor Network (1) 111-0017 (3) CRL-HC31 10102M (3) 111-0017 (3) POWER SUPPLY BOARD R1 R23 R24 VDR1 NTC 5 Cold 2700 2% 1/4W Metal Film 2700 2% 1/4W Metal Film VDR TNRG471 K (1) QW227 QW227 22-2246 22-2246 O > p 5 CD (1 ) Number on un It. COILS (RF-IF) ITEM No. FUNCTION MFGR. PART No. MAIN 30ARD L1 RF Choke L2 RF Choke L3 RF Choke L4 RF Choke L5 RF Choke L6 RF Choke ITEM No. POWER SUPPLY BOARD LI L2 L3 L4 L5 L6 L7 L8 L99 T1 FUNCTION RF Choke RF Choke RF Choke RF Choke RF Choke RF Choke RF Choke RF Choke Line Choke AC Line Choke MFGR. PART No. 19 PARTS LIST AND DESCRIPTION (Continued) When ordering parts, state Model, Part Number, and Description TRANSFORMERS ITEM No. FUNCTION REPLACEMENT DATA MFGR. PART No. OTHER IDENTIFICATION POWER SU T2 T3 PPLY BOARD Switching Power Switching Driver SPEAKER ITEM TYPE REPLACEMENT DATA No. MFGR. QUAM NOTES PART No. i PART No. SP1 2 1/4" PM, 8 Ohms FUSE DEVICES ITEM NO. DESCRIPTION MFGR. PART NO. NOTES DEVICE HOLDER F1 2.75A e 125V Fast-Acting MISCELLANEOUS ITEM No. 1 PART NAME MFGR. PART No. NOTES KEYBC PL1 SI thru S63 MAIN i cm CR2 YI POWEF SI j ARD Lamp Switch OARD LED LED Crystal 1 SUPPLY BOARD Switch Power Part of Keyboard Power, Red (1.8V 6 10mA) Audio Test, Red (1.8V 6 10mA) 14.31818MHz Power CABINET & CABINET PARTS (When ordering specify model, chassis & color) 20 KEYBOARD DECODER KEYBOARD ROM PROGRAMMABLE CLOCK L06IC ARRAY CONTROL LINES J9 CASSETTE DATA IN MUX JB JOYSTICK TIMER SHIFT REG MICROPROCESSOR TRI-STATE BUFFERS INPUT/OUTPUT UNIT VIDEO CONTROL LINES B D*TA ROMS J ADD MEMORY I R ADD. MANAGEMENT UNIT TRI-STATE FLIP/FLOP VIDEO DATA VIDEO VIDEO OUT DECODER/ DEMUX DEV _ADO_ DECODER/ i iosa RAMS SHIFT RE6 J11 VIDEO OUT TRANSCEIVER DATA PERIPHERALS PROM CONTROL READ DATA FLIP/FLOP WRITE DATA PROM ADO LATCH 0A-D J1 TO DISK DRIVE 1 32 TO DISK DRIVE 2 ail 130OW 31ddV MAIN BOARD GridTrace LOCATION GUIDE CI C2 C3 C4 C5 C6 C7 C8 C9 CIO C11 C12 CI 3 C15 CI 6 C17 CI 8 C19 C20 C21 C22 C23 C24 C25 C26 C27 C28 C29 C30 C31 C32 C33 C34 C35 C36 C37 C38 C39 C40 C41 C42 C43 C44 C45 C46 C47 C48 C49 C50 C51 C52 C53 C54 C55 C56 C57 C58 C59 C60 C61 C62 C63 C64 C65 C66 C67 C68 C69 C70 C71 C72 C73 C74 C75 A-3 A-3 A-4 A-5 A-6 A-8 A-9 A-14 A-1 A-1 A-1 1 A-1 A-2 A-1 A-2 A-1 A-2 A-3 A-4 A-5 A-6 A-7 A-8 A-1 3 A-3 A-4 A-5 A-6 A-7 A-8 A-1 3 A-1 1 A-14 A-1 5 A-1 3 A-1 3 A-1 1 A-1 2 A-14 A-3 A-4 A-4 A-5 A-6 A-8 A-9 B-1 B-2 B-3 B-5 B-7 8-2 C-6 C-1 C-4 C-5 C-10 C-1 2 D-12 D-1 D-3 E-1 E-4 E-5 E-8 E-10 E-1 2 E-1 4 E-1 4 E-1 4 E-1 4 F-6 F-8 F-10 C76 F-12 R27 C-10 C78 F-2 R28 E-1 C79 F-14 R29 E-1 C80 F-14 R30 E-1 C81 F-3 R32 F-13 C82 F-3 R34 F-2 C83 F-2 R35 F-2 C84 F-4 R36 F-2 C85 F-5 R37 F-3 C86 F-7 R38 F-2 C87 F-9 R39 F-14 C88 F-11 R40 F-14 C89 F-13 R41 A-2 C90 A-2 R42 A-2 C91 A-2 R43 A-1 C92 A-1 R44 A-1 C93 A-1 R45 A-1 2 CR1 A-2 R73 F-7 CR2 A-14 RP1 C-5 CR4 F-14 RP2 C-1 1 JO D-2 RP3 F-4 J1 A-2 UA11 A-1 1 J2 A-4 UA12 A-1 2 J3 A-4 RBI B-1 J4 A-5 UB2 B-2 J5 A-6 UB3 B-3 J6 A-8 UB5 B-5 J7 A-9 UB8 B-8 J8 A-9 UC1 C-1 J9 A-1 1 UC4 B-4 J10 A-1 1 UC5 C-5 J11 A-1 3 UC10 C-10 J13 A-14 UC12 C-1 2 J14 A-1 UD1 D-1 J15 A-14 UD3 D-3 J16 B-1 3 UE1 E-1 J17A B-1 4 UE4 D-4 J18 F-14 UE5 D-6 J19 B-1 4 UE8 D-8 L1 A-1 UE10 D-10 L2 A-1 UE12 E-12 L3 A-1 3 UE14 D-1 4 L4 A-1 UF4 F-4 L5 A-1 UF5 F-5 L6 A-1 UF6 F-6 01 A-14 UF7 F-7 92 A-14 UF8 F-8 04 F-2 UF9 F-9 05 F-14 UF10 F-10 06 F-2 UF11 F-11 R1 A-1 UF12 F-12 R3 A-1 2 UF13 F-13 R4 A-1 1 XI B-1 3 R5 A-1 2 X2 B-1 3 R6 A-1 1 X3 B-1 4 R7 A-1 2 X4 B-1 4 R8 A-1 3 X5 B-1 5 R9 A-1 1 X6 B-1 4 RIO A-1 3 X7 B-9 R11 A-1 3 Y1 F-2 R12 A-1 1 R13 A-1 3 R14 A-1 1 R15 A-1 2 R16 A-1 R17 A-14 R18 A-1 1 R19 A-14 Kz U A-1 1 R21 A-1 3 R22 A-1 3 R23 A-1 3 R24 A-13 R25 C-2 24 MAIN BOARD 25 MAIN BOARD 26 LOGIC CHART MAIN BOARD LOGIC PIN IC IC IC IC IC IC IC IC PIN IC PIN IC PIN IC NO. UA11 UA12 UB1 UB2 UB3 UB5 UB8 UC1 NO. UC4 NO. UC4 NO. UC5 1 P H L L L P L H 1 L 21 L 1 P 2 L # P P p P H H 2 H 22 L 2 p 3 L H P P P P L L 3 P 23 L 3 P 4 P H P P P P P P 4 H 24 P 4 H 5 P H P P p p p H 5 * 25 p 5 H 6 P H P P p P L P 6 H 26 p 6 p 7 H * P P P H L P 7 P 27 P 7 L 8 # H P P L L P L 8 H 28 P 8 H 9 H p p p H p p 9 p 29 p 9 L 10 » L L L H p p 10 P 30 p 10 M 11 H P P P H H H 11 P 31 P 11 H 12 L P P P H P P 1 2 P 32 P 12 H 13 H P P P H L P 13 P 33 P 13 P 14 H P P P H H P 14 P 34 P 14 H 15 * P P L P H 15 P 35 * 16 H P P P H H 16 P 36 * 1 "7 D r D r L 1 / r 31 □ r 18 P P P 18 P 38 H 19 L P L 19 P 39 P z u U n u n n 1 L u n PIN IC IC IC IC IC PI N IC PI N IC PIN IC PIN IC NO. UC10 UC12 UD1 UD3 UE1 NO. UE4 NO. UE4 NO. UE5 NO. UE5 1 p » p p p 1 L 21 P 1 L 21 P 2 H L p P P 2 P 22 L 2 L 22 P 3 H L P P P 3 P 23 P 3 P 23 P 4 H H P P L 4 P 24 P 4 P 24 P 5 H p p p p 5 p 25 H 5 p 25 p 6 H • P P P 6 P 26 P 6 H 26 P 7 H H H P L 7 P 27 P 7 L 27 P 8 H L P P H 8 P 28 P 8 L 28 H 9 H P H p p 9 p 29 p 9 p 29 p 10 H P L L H 10 p 30 p 10 L 30 P 11 H P L P P 11 P 31 P 11 L 31 L 12 L H P P P 12 P 32 P 12 H 32 L 13 H H P P L 13 P 33 P 13 H 33 P 14 H H P P H 14 P 34 P 14 P 34 P 15 H H P P 15 H 35 P 15 H 35 P 16 H H P P 16 H 36 P 16 36 P 17 H p p 17 H 37 p 17 p 37 H 18 P P P 18 P 38 P 18 P 38 P 19 P P P 19 H 39 P 19 P 39 P 20 P H H 20 P 40 P 20 P 40 P 21 P 22 P 23 P 24 H NOTE: Logic probe readings taken in Power Up mode, with- out Disk II Interface Board inserted, no keys press- ed unless otherwise noted. Logic Probe Display L = Low H = High P= Pulse # = Open (No light On) (1) Probe indicates L when CONTROL key is pressed. (2) Probe indicates L when SHIFT key is pressed. (3) Probe indicates H when any key is pressed except the CONTROL, SHIFT, CAPS LOCK, RESET and APPLE keys. (4) Probe indicates P when any key is pressed except the CONTROL, SHIFT, CAPS LOCK, RESET and APPLE keys. (5) Probe indicates H when CAPS LOCK key is up. (6) Readings taken after pressing SPACE bar. 27 LOGIC CHART (Continued) MAIN BOARD LOGIC (Continued) PI N IC PI N IC PI N IC PI N IC PI N IC PI N IC PI N IC PI N IC NO. UE8 NO. UE8 NO. UE10 NO. UE10 NO. UE1 2 NO. UE12 NO. UE14 NO. UE14 1 H 15 P 1 H 15 P 1 L(6) 13 P 1 P 21 L 2 P 16 P 2 P 16 P 2 L(6) 14 P 2 P 22 L 3 P 17 P 3 P 17 P 3 L(6> 15 P 3 P 23 L 4 P 18 P 4 P 18 P 4 H(6) 16 P 4 L 24 L 5 P 19 P 5 P 19 P 5 L(6) 17 H 5 L(3) 25 L 6 P 20 L 6 P 20 L 6 L(6) 18 L 6 L(6) 26 L 7 P 21 P 7 P 21 P 7 H(6) 19 L 7 L(6) 27 L 8 P 22 P 8 P 22 H 8 H(6) 20 P 8- H(6) 28 H(1 ) 9 P 23 P 9 P 23 P 9 P 21 H 9 L(6) 29 H(2) 10 P 24 P 10 P 24 P 10 P 22 L(5) 10 L(6) 30 H 1 1 P 25 P 1 1 P 25 P 1 1 P 23 H(6) 1 1 L(6) 31 L 12 P 26 H 12 P 26 H 12 L 24 H 12 H(6) 32 P 13 P 27 H 13 P 27 H 13 H(6) 33 P 14 L 28 H 14 L 28 H 14 H(6) 34 P 15 L 35 p 16 L(4) 36 P 17 L 37 P 18 L 38 P 19 L 39 P 20 L 40 P PI N IC PI N IC PI N IC IC IC IC IC IC IC IC IC NO. UF4 NO. UF4 NO. UF5 UF6 UF7 UF8 UF9 UF10 UF11 UF12 UF13 1 P 13 P 1 P H H H H H H H H 2 P 14 P 2 P P P P P P P P P 3 P 15 P 3 P P P P P P P P P 4 P 16 P 4 P P P P P P P P P 5 P 17 p 5 p P P P P P P P P 6 P 18 L 6 P P P P P P P P P 7 P 19 P 7 P P P P P P P P P 8 P 20 P 8 L H H H H H H H H 9 P 21 L 9 H P p p p P p p p 10 P 22 P 10 P P P P P P P P P 1 1 P r D r 1 1 P r D r P r P r P r P r P r P r P r 12 L 24 H 12 p p p p p p p p p 13 p p p p p p p p p 14 p p p p p p p p p 15 p p p p p p p p p 16 H L L L L L L L L NOTE: Logic probe readings taken in Power Up mode, with- out Disk II Interface Board inserted, no keys press- ed unless otherwise noted. Logic Probe Display L = Low 1-1 = High P = Pulse * = Open (No light On) (1) Probe indicates L when CONTROL key is pressed. (2) Probe indicates L when SHIFT key is pressed. (3) Probe indicates H when any key is pressed except the CONTROL, SHIFT, CAPS LOCK, RESET and APPLE keys. (4) Probe indicates P when any key is pressed except the CONTROL, SHIFT, CAPS LOCK, RESET and APPLE keys. (5) Probe indicates H when CAPS LOCK key is up. (6) Readings taken after pressing SPACE bar. 28 LOGIC CHART (Continued) DISK II INTERFACE BOARD LOGIC PI N NO. IC UA2 IC UA3 IC UB2 IC UB3 IC UC2 IC UC3 IC UD2 IC UD3 1 P H L P P P L P 2 H P H P P P H P 3 P P P P P P H P 4 H P H P L P H P 5 L P P P L P L P 6 H P L P L P H P 7 L P L P L P L P 8 L L P P L P L P 9 H P L P P P H P 10 H P L L L L H L 11 P P H P P L H P 12 P P P P P P L P 13 P P P P P P * P 14 H P H P P P H P 15 P L H P H 16 H L H P L 17 P P P 18 P P P 19 P P P 20 H H L 2 O > m TJ m 5 NOTE: Logic probe readings taken while running the fol- lowing program. 10 D$ = CHR$(4) 20 PRINT D$; "OPEN SAMS" 30 PRINT D$; "WRITE SAMS" 40 FOR X = 1 TO 50 50 PRINT "THIS IS A TEST" 60 NEXT X 70 PRINT D$; "CLOSE" 80 GOTO 20 Logic Probe Display L= Low H = High P = Pulse # = Open (No light On) 29 SAFETY PRECAUTIONS 1. Use an isolation transformer for servicing. 2. Maintain AC line voltage at rated input. 3. Remove power from the Computer before servicing or installing electrostatically sensitive devices. Examples of typical ES devices are integrated circuits and semiconductor "chip" components. 4. Use extreme caution when handling the printed circuit boards. Some semiconductor devices can be damaged easily by static electricity. Drain off any electrostatic charge on your body by touching a known earth ground. Wear a commercial- ly available discharging wrist strap device. This should be removed prior to applying power to the unit under test. 5. Use a grounded-tip, low voltage soldering iron. 6. Use an isolation (times 10) probe on scope. 7. Do not remove or install boards, floppy disk drives, printers, or other peripherals with power On. 8. Do not use freon-propelled sprays. These can generate electrical charges sufficient to damage semiconductor devices. 9. The Computer cabinet is equipped with vents to prevent heat build-up. Never block, cover, or obstruct these vents. 10. Instructions should be given, especially to children, that objects should not be dropped or pushed into the vents of the cabinet. This could cause shock or equipment damage. 11. Never expose the Computer to water. If exposed to water, turn the unit Off. Do not place the Computer near possible water sources. 12. Never leave the Computer unattended or plugged into the AC outlet for long periods of time. Remove AC plug from AC outlet during lightning storms. 13. Never use liquids or aerosols directly on the Computer. Spray on cloth and then apply to the Computer cabinet. Make sure the Computer is disconnected from the power line. SCHEMATIC NOTES — «— Circuitry not used in some versions Circuitry used in some versions e See parts list * Ground rrtrt Chassis Waveforms and voltages taken from ground, unless noted otherwise Voltages, Waveforms and Logic Probe readings for main board taken with Computer in Power Up mode, no keys pressed, unless otherwise noted. Voltages, Waveforms and Logic Probe readings for disk II interface board taken while running the following Basic program. 10 DS = CHR$(4) 20 PRINT D$; "OPEN SAMS" 30 PRINT D$; "WRITE SAMS" 40 FOR X = 1 TO 50 50 PRINT "THIS IS A TEST" 60 NEXT X 70 PRINT D$; "CLOSE" 80 GOTO 20 Waveforms taken with triggered scope and Sweep/Time switch in Calibrate position, scope input set for DC coupling on reference voltage waveforms. Switch to AC input to view waveforms after DC reference is measured when necessary. Each waveform is 7 cm. width with DC reference voltage given at the bottom line of each wave- form. Time in /*sec. per cm, given with p-p reading at the end of each waveform. Item numbers in rectangles appear in the alignment/ad- justment instructions. Supply voltages maintained as shown at input. Voltages measured with digital meter, no signal. Controls adjusted for normal operation. Terminal identification may not be found on unit. Capacitors are 50 volts or less, 5% unless noted. Electrolytic capacitors are 50 volts or less, 20% unless noted. Resistors are VzW or less, 5% unless noted. Value in ( ) used in some versions. Measurements with switching as shown, unless noted. Logic Probe Display L= Low H = High P = Pulse * = Open (No light On) (1) Probe indicates L when CONTROL Key is pressed. (2) Probe indicates L when SHIFT key is pressed. (3) Probe indicates H when any key is pressed except the CONTROL, SHIFT, CAPS LOCK, RESET and APPLE keys. (4) Probe indicates P when any key is pressed except the CONTROL, SHIFT, CAPS LOCK, RESET and APPLE keys. (5) Probe indicates H when CAPS LOCK key is up. (6) Readings taken after pressing SPACE bar. (7) Logic readings not taken. 30 ahtk LINE DEFINITIONS * Address Lines Q3 General Purpose Clock A * u Acknowledge RAO Thru RA7, RA9, RA10 ALTVID RDY. . . Rpadu ANO Thru AN3 RESET .. . . . tt\ ™tf" n „ Cassette Enable READ DATA Read Data Capital (Letter) Lock ROMEN1, ROMEN2 ROM Enable Lines CLKEN Clock Enable R/W Read/Write ° M "? ATE ■ Ciei " R/W80 Read/Write 80 Character CNTL Control SEGA COXX SEGB C06X.C07X SEROUT Serial Output CXXX SHFT Shift DMA Direct Memory Access SPKR SDeaker DO Thru D7 Data Lines STB Stro be DEV1 Thru DEV7 Peripheral Device Select SW0/OAPL cm A nn E1 ' ENABLE2 Enable SW1/CAPL Switch Capital ENKBD Enable Keyboard SW2 ENTMG SYNC Sync ENVID Enable Video VC EN80 Enable 80 Character Width VIDO Thru VID7 FRCTXT V|D7M 2 Graphics WNDW Window Hu Horizontal WRITE DATA Write Data l/OSTROBE Input/Output Strobe WRITE PROTECT Write Protect \"" WRITE REQ Write Request IOSEL Input/Output Select X0 Thru X7 IRQ Input Request Y0 Thru Y9 k^trr Keyboard 3.58M 3.58MHz KSTRB 7M 7MHz LDPS Load Parallel to Serial 14M 14MHz SSSSf 0f Buffered Data Lines 80VID '.'.'.'.'.'.'.■.■.V.80Character Video MD "N/OUT Buffered Data Input/Output /xPSYNC "° T0R0N Motor On O0 Phase 2 " R „ Mem °^ Read 01 Phase One O > NMI Non-Maskable Interrupt OA Phase A ° 2 PDLOThru PDL3 Game Paddle Lines OB [[Z" P Tall B F ? 0C Phase C= m KHAi> OD Phase D Any Bar above any alphabetical or numerical combination indicates line level in a low (0) state. 31 IC PINOUTS & T i IE 7 114 113 11! Ill mo r^9 IDENT II, 12 UA2, UB2 TOP VIEW E B C BOTTOM VIEW E B C Q2.Q3 .mm. FRONT VIEW 11, Q3. Q4 BOTTOM VIEW TUT RAG SCRI BOTTOM VIEW BOARD 10 TOP VIEW II THRU 17 TOP VIEW 117 TOP VIEW 3 78 27 26 4 25 74 25 5 _ SN741S244N vci: IY2 —y\ 2A3 ^>J_2M tri ST/ut buhtr TOP VIEW 74LS374N 17 6 16 7 OUTPUT CONTROL -0E -QE 4JL CK D -QE 4Q QE -QE CK E CK D OND TRI-STATE FLIP/FLOP TOP VIEW 2cr UA11 TOP VIEW Ql. Q2, Q4, BOTTOM VIEW vcc R650240 ROY 810UT IRQ NC NM SYNC VCC AO Al A2 A3 A4 A5 A6 A7 A8 A9 A10 All IHJIN NC NC R'W DO Dl DZ D3 M 05 D7 A1S UC4 MICROPROCESSOR TOP VIEW NE558N 18 1 15 7 TIMING B 717 PIN VIEW 118. 119 TOP VIEW P|| 32 T6 4.4V WRITE DATA PHOTO C1RCUITRACE SCHEMATIC CIRCU1TRACE -[77] FOR TERMINAL GUIDES AND NOTES SEE PASES 5,30,32 SN74LS132N PART OF UA2 SN74L5132N PART OF UA2 MOTOR ON MOTOR ON ENABLE2 ENABLE1 CABLING I LINE IDENTIFICATION ASSIGNED FOR REFERENCE 74LS05PC i*VHi — 1 PART OF UB2 -^5 1? r-AO- £ — A1 ■ A2 ■ — A3- I.7V 2.1V .IV 2.1V .1V 2.1V N9334N .IV 5.0V UC2 .IV LATCH .1V 4.1V T5" s.mao ■*A- -08- 0C- (to- T2~ p IT" p READ J2 'v " DATA WRITE gC'" DATA lit.., WRITE £js REQ "loY WRITE JK~" PROTECTlo7..., 3 J2' 3 ... J2' 5J "J2l ■J2'„ is ; 13 f — 4 it; J2 - 19 !.— , MS J2l S.OVfS) 12 I—, J2' dx -11.9VtH) ENABLE2 9 f mT - 0A - 0B 0C L- 00 ££kJ READ £U DATA Jif WRITE J1 v DATA fit.., WRITE J1 s REO "IqJ I WRITE JK~" PROTECT 20 u~. Jl ji n.svffl) is r Jlr" 7i~i- 19 i 17 r S.OVfB) 12 r.... 9 r : ; ■ ENABLE! ^ ji r — -11.9V(B) 0A - 0B 0C ' 0D 2 r.„. _jir- 6 i- it b r TO DISK DRIVE 2 TO DISK DRIVE 1 > m tj 1 m A PHOTOFACT STA NDARD NOTATION SCHEMATIC wuh HE5BEB3 © Howard W. S»ms & Co.. Inc. 1985 SEE SCHEMATIC NOTES BEFORE TAKING VOLTAGES, WAVEFORMS AND LOGIC PROBE READINGS ONS ON PAGE 31 DISK II INTERFACE BOARD 33 no 120VAC OMC J2J P21 CAUTION. BE SURE TO USE AN ISOLATION TRANSFORMER FOR SERV1C1N6 THE POWER SUPPLY h ^ n 3.1V 5/is ehStt FROM THE ER OF 01 -IV 1.4V TAKEN FROM THE" EMITTER OF 01 SEE SCHEMATIC NOTES BEFORE TAKING VOLTAGES, WAVEFORMS AND LOGIC PROBE READINGS RP3 3200 — w- 3200 — vw — 3200 — v\/v— 3200 — w. — 3200 — WV— 3200 -wv- 3200 3200 3200 -2.1V R16 390 L I CIO .01 1KV 1.5V 5us — J--.5V TAKEN FROM THE EMITTER OF 01 HU I */ /D11 c - /1M606 S.2 f t KJ TAKEN FR EMITTER 2SB621R 03 RES 2V 5ras ' 4.4V 3.9V e R2Si R24 100Kf2700f .22 2* 100V R22 470 C1B±R32 ISO* e R23 2700 2X 2.SV CI 7 .022 -4£ T18231 1C1 RE6 21 3.7V R21; !2K m s.ov R20 56 R19 {m_nnm_ RH 270 ■WV— n 1 i H «1S 8.2 m s.ov 05 1N4606 . . ra S.OV "ml 1N4606 -M— R13 270 IK — vw — CI .22 PHOTO CJRCUJTRACE = ||| SCHEMATIC CJRCUJTRACE - fTT| FOR TERMINAL GUIDES AND NOTES SEE PA6ES 5,30,32 L A PHOTOPACT STANDARD NOTATION SCHEMATIC WITH CircuiTrace © Howard W. Sams & Co. 1985 POWER SUPPLY 34 A PHOTOFACT STA NDARD NOTATION SCHEMATIC with © Howard W. Sams & Co. 1 35 MAIN BOARD 11 14 LI a *| 12 HI . 6 1 11 LI / 7 1 J 16 L 1 , 6 1 S HI J 1! 1 1 H' , V, 1 3 L J e HD74LS10P PART OF UC5 SEE LINE DEFINITIONS ON PAGE 31 36 J11 NTSC VIDEO OUT JLATOR 5 ,6V .•V .9V 1.1V 1.0V .7V 1.0V 1.3V 74LS245N ,8V .8V UB2 2.4V 2.0V TRANSCEIVER 1.3V 1.5V 2.3V 2.6V OV 19 ■00- •01 - ■ D2 •03- D4 ■ D5 •06- ■07- P 2T P 22 P p 1.9V 4.0V .9V 4.0V 3.7V 4.0V 3.3V 4.0V DM74L5154N 1.9V 4.0V ucio 4.0V 4.0V DECODER/ DEMUX 4.0V 3.8V 4.1V 4.0V 4.1V 4.0V 4.0V 4.0V 4.0V 4.2V 1 XT' VdEVT- "ft 5.0V BevT- DEV2- 0EV3- DEV4- i | DEVT = , TT DEV2 0EV3 DEV4 = = _L _L J _ DEV5 DEVS 0EV7 • STfl - •C06X- ■C07X- £-NC COXX- ;47 19L/*^-A, AO — < 2 ! 41 19 I- AO A1 A2 A3 A4 A5 A6 A7 AS J1 - 1NH — 2 -A 4 H* A9 — ^11 A10 <Jl2 All <[l3 A12 <{l4 A13 <JlS AH <^16 A15 —"^17 RESET ^31 1/0STR8 — <^ 20 NMl <^29 _NCH 27 24-L IRO <JsO NC i 41 19 J2 32 NC— ^28 • 7M <j36 ■ 03 <^37 • 01 <^38 -jjPSYNC-<^39 ■ 00 <J<0 • R/W <^ 10 • ROY <^21 • DMA (J 22 23- ! 1 35 "V'V 1 27 24 -28 23 J3 NC 41 ItlA. 41 J4 24- -27 1 35 V NC NC il 1 igi-A-.A, ' 41 19 J5 -27 24- 24- -27 JE X SYNC —4 /V. 41 19 i 49 > DO J7 )[> D1 - 46 ^ D3 - 45 J> D4 - 44 J> D5- 43 J> 06 - 42 J> 07 - 50 b] MD4 MD5 13 S RA4 - 14 }> RA5 MD6 <J 17 46 J> RA6 MD7 <Jl6 9 J> RA7 - — 5nd6 <J 7 56 J> (HI - HO ^47 57 S RTT5- -! ! ■ SYNC 3 r-<^28 -27 24- 23 — t— 28 23 — f— 28 ~ V. 28 23-4-28 j 23-*-28 i3 <^ - l 1 35 iV' : i 35 35 t\r 33 34 25 '24 ill.SVM} i-11.9V0U l -5.0V s.ov NC 45^-VIDO- 42^>— VJD1 GR — <J 58 41 S VI02 FRCTXT-^S5 38 J> VID3 AN3 <[S0 22 J> VID4 CLR6ATE-<J 24 19 J> V1DS VC <J 5 18j> VID6 SE68 ^54 15 J) V1D7 1 35 V* T X7 L 8R 1 35 V" V 10SEL1 T NC I0SEL2 T NC r NC J0SEL3 J_ J0SEL4 T NC T NC 10SFX6 I0SEL5 — i L J0SEL7 ENKBO 3.58M i JO [ MDO <J 44 51 p RAO - MD1 <^43 10^— RA1 - MD2 <^40 49^ RA2 - MD3 <j 39 48 J) RA3 - SE6A <J 8 BOVlD -<^2S ENTMG 34 J> tOPS- 33 J> — PCAS- — ENVID -<j29 32 1> 14M - — aTtvTd-^27 53^ — 03 - -C07X <j 6 36j> — 01 - - CA5EN -<j 37 35 R/W80 - -<^60 23 J> 00 - 4 [> PRAS- ^— <J31 11 J>-R0MEN1 - 12j>-R0MEN2 I — <^30 59 J> 7M - Q] i 1 J> 3.S8M- S m | 2 ^- V107M - 26 J> EN80- ! 52^> R/W - i J ^ APPLE MAIN BOARD MODEL Me 37 KEYBOARD S44 531 SI 6 SI "1 2 A TAB ESC 514 542 S56 S29 DELETE RETURN \ SB2 ) S63 ) ' ) S13 545 X 533 S17 f 1 J SAB C S32 5 518 V 1 ' 3 547 536 519 f H T J ' CJQ E9i CIA 33 I 70 548 534 520 B F R 549 M Ul 550 N .178 -»- S35 6 523 y T J178 S37 J S21 T ■JLH1 .JL t 526 P 558 SPACE S61 541 ' 528 f S51 < 512 SS2~ J178 56 , 5 ' T J17B 538 K S23 U SS3~ S40 S8 E 7 S24 I J- 23 J17B 25 jipipiriPiriririT T •— ' T — ' T Ji78 S39 L S25 510 t£ 9 J17A J17A -«— V2 J17A Y3 J17A J17A -<4— Y5 10 J17A re J17A J17A Y7 J1 7A J178 14 22 , 22 14 J^ 18 J178 J17B 16 J17B J17B 21 -» 19 J17B J1.78 515 RESET S30 543 554 CONTROL L SHIFT R SHIFT J17B J17B ' T -» 11 J17B I , , 559 557 SSS 15 | I r SOLID APPLE OPEN APPLE CAPS LOCK J17fl ' £$ . , ft fiJUf J17fl4> 3i R1 JITS'* 5 J17o4? 7 J17fl4> 9 ' s.ov IR1 J17BSp 5 J17B^p 7 7A • XO J17A 18 -«-xi 16 J17, X2 X3 X4 21 J17A «-xs J17A 19 J17, 9- 26 J17i 17A r X7 -shfi J17A 11 J17A <<eCNTL RESE 1 J17A^ 5W1/CAPL SWO/OAPL CAPLOOC I I L A PHOTOPACT STA NDARD NOTATION SCHEMATIC with HEEsninss © Howard W Sams & Co 1985 KEYBOARD, MA 7 - YO- - Y1 • - Y2- - Y3- - Y4- - Y5- - Y6- - Y7- ■ YB - - Y9- -XO- ■ X1 - -X2- ■ X3- ■ X4- -xs- ■ X6- • X7- -17 L L -2TT T7 ~73 L L L ~3B" p To" p -3? p SHFT NUMERIC PAD Tie — 4- vo J16 1 < Y1 - 2 JIB <-Y2 - JIB S < Y3 - 3 JIB J16 4 < Y5 S JIB JIB 9 < XS 11 J16 <r~XB JIB 10 < X7 B JIB 'part of I 6RP2 1000 - 1 _ Z. . 37 P —55 P —35 P ST p ~35 H(2) - 2T HCD "38" 1000 _ J 03 S.OV ■1.8V -1.6V -1.8V 1.6V -i.ev '1.6V 1.8V 1.8V 1.6V -1.6V -1.6V ■1.5V ■1.5V 1.5V -1.5V -1.5V ■1.5V -1.6V 4.9V 4.9V 4.8V ov OV ov 4.SV OV OV 4.5V 4.9V .2V 1.6V -1.9V 2.4V -11.9V -4.3V -1.6V OV e ov AY-5- 3600-PRO UE14 DECODER H(6> T4~ Ti L(6) 10 LC6) T~ HC6) T L(S) 7 — LOB "B — h;b T3~~ H(8) •NC 1ec70 a N470 R32 JIB /< POLO ' 5 JOYSTICK J8 8 -PDL1 SWflAMPL- <SW1 1 J8 1 J8 XB Rn 1—1 ,0 ° POLO -fHBOr— PDL1 -J-|6iT-^vv— .0221 PDL2-J- 1 ^} - R22 100 -Wv- J | PDL2 4 C35T J« _ 100 - * PDL3 PDL3 -J-HB3I — w $ J8 034 T < SW2 - 6 1 - C07X ■ SEE SCHEMATIC NOTES BEFORE TAKING VOLTAGES, WAVEFORMS AND LOGIC PROBE READINGS BOARD "38" J 11 L (6) 1 Id L (6) 3 9 HOD 3 8 LCD 4 7 LCD 5 6 1MB 6" 13 HtO 7 15 A H(fO T4 - ^— NC p N470 - ' R32 p 100K I 5V lOjts ov |~4V 1 lOus am — Ii ^ ^ ^ 4.8V ov L -11.9VM) ■32-NC i - AKD — U4> TT KSTRB - - KBD S.OV - ENKBO R27 1000 S.W X2 —cr* 16 19 .sv .3V .7V I. .BV 2.4V 1.3V 3.SV TT NC e 342-01 32-B UE12 KEYBOARD RON ov 3.9V OV P P TcT p TT P T p TT p TT p MOO MOl MD2 MD3 MD4 MOS H06 12 21 24 X1 S.OV 5.0V I ov s.ov NE558N 5.0V , UA12 K °V " TIMER 15 H n H 13 H .PART V 1 e RP2 I 1000 ' 000 f 1000 1000 m s.ov irj -'J TIC NOTES BEFORE 1AGES, WAVEFORMS PROBE READINGS RIB 1M CASSETTE jq Ml R4 _ .1 _ 12K" @ [|4}H(-{re}-vw e RC741N NC"*" NC JJf R12 12K RU 12KT' j, -S.OV r~i "ov ov f NC I CD m f s.ov s.ov 12 R20 1* ENVID I -S.OV SV1/CAPL SKO/OAPL 3 07 S.OV s.ov SN74LS2S1- NOS UC12 MUX 4.4V OV ov 4.1V T - MDO - MD1 MD2 MOS - M04 - MOS - MOB - MD7 -01 n s.ov — IRQ NMT H 40 H 4 N 6 M — lil PART OF | ORP1 3300f; SN74S02N PART OF UB8 X4£— SN74S02N PART OF UBS s.ov 3> 9V p (T)|lJ 4137 5V 5us ,9V ,7V 1.0 .BV 2.4 1.3 2.9 Rl 5.0 5.0 5. 5.0 I PR FOR TERMINAL 611 JOES AND NOTES SEE PAGES 5,30,32 PHOTO CIRCUITRACE SCHEMATIC CIRCUITRACE -[77) LINE IDENTIFICATION ASSIGNED FOR SEE LINE DEFINITIONS ON 40 H H — < : p *i> 9 P M 2 10 4 p'45 g" I'm 8 p *S 17 i 4 M 15 !%1 13 16 11 PART OF 6RP1 3300 3300 5.0V s.ov MICRO- PROCESSOR SN74S02N PART OF UB8 I- -IV S.OV 21 TRI-STATE BUFFER 2.1V .7V 342-01 35-B 2.1V 6 1.0V UES 1.9V .9V CD-ROM .9V 3.4V 5.0V f -NC TRI-STATE BUFFER FFER -jg-, TalH D3 5.0V DM74LS12SAN PART OF UE1 T=4 T5 "55 A11 2.1V C196S9 2.1V e 1.0V UE10 i.9v .ev EF-ROM .« 2.4V 4.0V jiPSYNC TT 21 1.7V ZSV 2.3V S.7V GUIDES AND NOTES 30,32 J! TRACE ■ HI LilTRACE -pTl EN80 l_ DM74LS125AN !_ R/W PART OF UE1 R/WBO 10 4.0V 5 10. PART OF I e RP2 1000 L - ~T MEKf, NES R0MEN1 ^PART OF I e rpi 3300 3300 .IV .IV OV .IV «.0V 3.3V 2.2V 3.2V 4.0V 1.8V 2.0V 1.1V .2V 3.7V 3.4V 5.0V 3.9V 5.0V S.OV 19 17 V 5.0V -cxxx IFICATION M REFERENCE I/OSTRB - 00 MPS4258 06 OSC MPS4258 H.3181Mfc 04 OUTPUT Y1 HsT~ I yi JTsT 1 -» J f® R93fc77f * 10f 11.6V CO INE DEFINITIONS ON PAGE 31 MAIN BOARD APPLE MODEL lie .3V i.ov .av 74LS374N M .91 UD3 - 2.4V 3.BV TRJ-STATE FLIP/FLOP rrr v,D5 - S.OV S.9V 1.9V 344-0020-/ .7V .W S.7V UES .SV input/output 1.9V UNIT .« I— vc - ENVIO •BN5k- R2S 1000 .av e 4.9v 342-01 33-/1 .SV 4.9V UF4 .3V 4.9V VIDEO p 14 p 12 11 p 11 13 p 10 14 " 1 » J 5 IS 4 3 f3300 3300 faoo S.OV -LDPS- -AN2- _ 3. C79 - SPKR _m ■ x iKzD- PART OF | RP1 3300 - "T JIB « 1 I _ — r 4V 5ms L 0V J10 CASSETTE OUT ■HO- CLR6ATE RESET • 5.0V 10/is SEE SCHEMATIC NOTES BEFORE TAKING VOLTAGES, WAVEFORMS AND LOGIC PROBE READINGS NC- J1S ANO AN1 AN2 — AN3 r— PDLO J15 — PDL1 -[ST] — < 10 , , J15 — P0L2 . . J15 PDL3 -{S)-< J15 SWO/OAPL— < J15 — SW1/CAPL— < J15 — SH2 — — < 4 — STB 14M e 74166N UF5 SHIFT REGISTER S.OV 6V L -1V A PHOTOFACT STA NDARD NOTATION SCHEMATIC with QQ33QZ&9 © Howard W. Sams & Co. 1985 35 MAIN BOARD fab** ij R8 75 J11 NTSC VIDEO OUT J r? 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