COMPUTER FIELD SERVICE MANUAL
Contents
1. bus interface PBI provides an un buffered direct connection to the address data and control signals shown below it could be used to interface peripherais parallel bus devices and external applications Figure 1 12 illustrates the pin assignments of the parallel bus interface Parallel Bus Specification GROUND GND ADDRESS OUTPUT AO ADDRESS OUTPUT A2 ADDRESS OUTPUT Ad ADDRESS OUTPUT 6 ADDRESS OUTPUT 7 ADDRESS OUTPUT 9 ADDRESS OUTPUT All ADDRESS OUTPUT A13 GROUND GND DATA BI DIRECTIONAL DO DATA BI DIRECTIONAL D2 DATA BI DIRECTIONAL DATA BI DIRECTIONAL D GROUND GND PHASE 2 CLOCK OUTPUT B02 N C RESERVED INTERRUPT REQUEST INPUT IRQ N C RESERVED N C RESERVED COLUMN ADDRESS OUTPUT CAS MATH PACK DISABLE INPUT MPD GROUND GND N C RESERVED AUDIO IN AUDIO iQ A 12 iQ iQ POOLE BOTTOM EXTSEL EXTERNAL SELECT Al ADDRESS OUTPUT ADDRESS OUTPUT A5 ADDRESS OUTPUT GND A8 ADDRESS OUTPUT A10 ADDRESS OUTPUT A12 ADDRESS OUTPUT A14 ADDRESS OUTPUT A15 ADDRESS OUTPUT Di DATA BI DIRECTIONAL D3 DATA BI DIRECTIONAL D5 DATA BI DIRECTIONAL D7 DATA BI DIRECTIONAL GND GROUND GND GROUND RST RESET OUTPUT RDY READY INPUT EXTENB EXTERNAL DECODER OUTPUT REF REFRESH OUTPUT GND GROUND RAS ROW ADDRESS STROBE OUTPUT LR W LATCHER READ WRITE OUTPUT RESERVED N C GND GROUND Figure 1 12 PBI Connector Pin Ass2. ROM Self Test Enable and BASIC Enable Parallel Bus Interface Direction X Controller Ports SIO Interface POT Control Scan Monitor Jack Trigger Outputs Keyboard mj Audio i Summation si Circuitry Function CPU Address Data Control Lines Video m4 Summation Circuitry 29 BASIC ROM Operating Systems ROMs be Up to 16K Power ON Reset E Figure 1 2 Functional Block Diagram 800XL Computer 1 3 Field Service Manual Monitor Television 2v DI BLECIRBICAL THEORY DIGITAL HARDWARE The digital hardware consists of The 6502C CPU microprocessor o The Alphanumeric Television Interface Controller ANTIC o The Graphics Television Interface Adaptor GTIA o The POT KEYboard Integrated Circuit POKEY The Peripheral Interface Adaptor PIA The Memory 5 ROM 64K RAM Atari BASIC ROM Rev o Miscellaneous Logic Memory Management Unit MMU Delay Line Parallel Bus Interface PBI 6592C CPU Microprocessor The 6502C CPU microprocessor contains register flags interconnections arithmetic logic control logic and all recognized operation codes The characteristics of the microprocessor inciude Byte oriented structure 151 opcodes Decimai and binary arithmetic modes Seven add
3. Test 800XL Computer 2 1 Field Service Manual Press the SELECT key to move the selection indicator until you reach the desired Press the START key to begin the test CAUTION Self Test will not go into the Attract Mode Do not leave Self Test screens on for any length of time maximum seven minutes since screen burning can occur DESCRIPTION OF SELF TESTS MEMORY TEST Purpose test the ROM RAM and ANTIC chips Format Two long bars displayed at the top of the screen represent the 16K Operating System ROM Below them are 48 blocks each representing 1 lt of RAM The remaining 16 of RAM is available only with certain software programs and is not tested at this time When either ROM or RAM is being tested the corresponding bar segment color is white If the ROM or RAM tests good the bar color changes to light green If the ROM or RAM tests defective the color changes to red Once a ROM or RAM has been tested and found defective the bar or specific block remains red and the memory is not tested again on subsequent test passes The MEMORY TEST continues testing until either the HELP or RESET key is pressed NOTE If RESET is used to exit a test the OS will return to Basic not the Self Test You must then press and hold OPTION and power up the console as before AUDIO VISUAL TEST Purpose To test the ANTIC and POKEY chips Format The screen displays a music staff and treble clef A sequence of s
4. R98 105 107 108 RII R113 134 137 R114 8116 RNI 4 51 800XL Computer Description Resistor Resistor Resistor Resistor Resistor Resistor Resistor Hesistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor 1 4W 100 Ohm 1 4W 1 6K 1 4W 36K 1 4W 18K 1 4W 9 1K 1 5 W 4 7 1 4W 750 Ohm 1 4W 1 2K 1 4W 75 Ohm 1 4W 47K 1 4W 1 8K 1 4W 2 7K 1 4W 220 Ohm 1 4W 33 Ohm 1 4W 27 Ohm 1 4W 470 Ohm 1 4W 1 5K 1 4W 51 Ohm Network SIP 470 Ohm Switch Vertical Power SPDT Switch Channel Select IC Dual Op Amp LM358 IC Decoder 74LS138 IC Mem Mngt Unit MMul B IC 16K X 8 OS ROM IC SK X 8 ROM Rev B IC ANTIC IC CPU 6502 IC 64K X 1 DRAM IC GTIA IC AND Quad 74LS08 IC Hex Inverter 74LS14 IC Hex Buffer CMOS CD4050B Field Service Manual Part Number 14 5101 14 5162 14 5363 14 5183 14 5912 14 5472 14 575 14 5122 14 5750 14 5473 14 5182 14 5272 14 5221 14 5330 14 5270 14 5471 14 5152 14 5510 C061 668 04 061022 019702 01 061702 061428 061 618 061 598 060302 C021697 C014806 C060612 014805 017097 061850 010816 Location U22 U23 U24 25 U26 27 128 129 U30 Wi XUI XU18 19 30 XU2 9 16 20 24 28 XU3 XUL 5 117 8 17 22 23 Y 800XL Computer PARTS LIST Description IC POKEY IC PIA IC CD4051B IC Multiplexer 74LS1 58 Latch
5. 3 4 stroke 56 key alphanumeric keyboard that includes special characters and controls space bar four function keys HELP key and power indicator The function and HELP keys are discussed below FUNCTION KEYS RESET Interrupts and restarts the operating system OS or cartridge When pressed while the computer is ON this key enables the BASIC START Starts the game or program SELECT Selects different program or game variations OPTION Allows the player to choose variations of a program If the OPTION Key is not depressed and held at the time the computer is turned ON the built in BASIC is automatically enabled If the OPTION key is depressed and held at the same time the computer is turned ON the on board BASIC is disabled and when there is no cartridge or diskette in the system the Self Test menu appears HELP Returns to main self test menu from individual test and for future software development for user help functions If you are familiar with 1200XL operation this key does not function the same S00XL Computer 1 1 Field Service Manual MECHANICAL THEORY The 800XL computer console contains a single motherboard which houses all the chips of the system and provides connectors for interfacing external modules to the console It includes the CPU RAM OS and BASIC ROM s The motherboard uses a common address bus data bus and clock lines The sixteen line address bus allows the microprocessor to directly addre
6. 33 R W Read Write Trigger 1 9 x 5 Chip Select 1 Trigger 2 T2 10 31 Lum3 Luminance Line Trigger 3 13 H 30 D2 Phase 2 Input Option S 2 29 Clock Out tart 51 13 1 23 OSC Oscillator Input Select 52 15 27 YCC Power Keyboard Click 53 15 26 HALI HALT PAL Color Delay PAL 16 25 CSYNC Output Syne Color Delay CADJ 17 25 LUM 2 Luminance 2 Output Alpnanum Data 0 ANG 18 23 LUM 1 Luminance 1 Output Data 1 ANI 19 22 LUM 2 Luminance 0 Output Alphanum Data 2 AN2 20 21 COL Color Figure 1 5 GTIA Pin Assignments POT KEYboard Integrated Circuit POKEY The POKEY is a custom Large Scale Integrated circuit LSI chip It is used for audio generation Serial Input Output SIO Data and Clocks POT Controller interface scan and keyboard scan Figure 1 6 is an illustration of the POKEY pin assignments 800XL Computer 1 7 Field Service Manual Ground Data 3us 2 Data Sus Cata Bus 3 Data Bus Data Audio Data Sus 3 Address Bus Bus amp Address Bus Chase 2 Clock 7 Address Bus Pot Scan 3 Address Pot Sean 9 1 Read Write 10 i 11 12 terrupt 13 Serial Data 15 Serial Cutput Clock Pat scan 13 Clock Keyboard Response Keyboard Response 5 Y Power 17 input aa Scan KS 18 lard Sc E KE 19 K3 20 Figure 1 5 POKEY pin assignments The PIA is a general
7. 64 R35 R36 R38 800XL Computer PARTS LIST Description Cap Ceramic Axial 220pF 50 Cap Elec Axial 47uF 10 Cap Ceramic Axial 100pF 50V Cap Ceramic Axial 3 9pF Diode 154145 Connector Rt Angle 13 pin Connector Monitor 5 pin Connector Cartridge 30 pin Connector Rt Angle 9 pin Connector DIN Power 7 pin Connector Keyboard Header 24 Pin Inductor Ferrite Bead Inductor Axial 820uH Inductor Axial 100uH Inductor Axial 10uH Inductor Axial 22uH Transistor NPN 2N3904 Transistor PNP MPSA55 Transistor PNP 2N3906 Resistor 1 4W 2 2K Resistor 1 4W 2K Resistor 1 4W 6 2K Resistor 1 4 W 56K Resistor 1 4W 470K Resistor 1 4W 68K Resistor 1 4W 5 1K Resistor 1 4W 3 3K Resistor 1 4W Resistor 1 4W 3K Resistor 4W 240 Resistor 1 4W 1M Resistor 1 4W 10K Resistor 1 4W 33K Resistor 1 4W 680 Resistor Variable Trimpot 500K Field Service Manual Part Number C0141 80 05 24 100476 014179 19 C061 336 01 060607 2122925 C 214388 C014389 010448 C061 838 061793 C014384 017948 03 017948 04 018381 C014380 34 2N3904 014809 018991 14 5222 14 5202 14 5622 14 5563 14 5474 14 5632 14 5512 14 5332 14 5102 14 5302 14 5241 14 5105 14 5103 14 5333 14 5681 19 411504 Location R40 53 66 90 109 112 117 119 128 131 R46 R47 R48 R49 R50 63 31 34 92 94 R51 R54 R55 56 57 R89 R76 79 R91 R95 110 118 120 127 132 133
8. Bus Alphanum Data ANT 3 Data Sus Light Pen 07 Bus Alphanum Data ANA 5 RST Reset SYS RST RN ML 6 FOG Fast Phase 0 Clock Interrupt Output NMI 7 QU 0 Clock Refresh REP 4 93 Data Sus HALT HALT 9 D2 Data Bus Address Sus A3 10 Dt Data Bus Address Bus Al 12 Q2 Phase 2 Clock Address Sus 13 AR Address Bus Read Write R W 15 Address Bug Ready Output RDY ca A6 Address Bus Address Bug 410 16 7 Address Bus Address Bus A12 17 Ag Address Bus Address Sus 413 13 AS Address Sus Address Bus A18 19 Ail Address Bus Address Bus A13 20 VCC 35V Power Figure 1 4 ANTIC Display Processor Pin Assignments Graphic Television Interface Adaptor GTIA The GTIA interfaces with the ANTIC processor on one side and with the video summation circuitry on the other Its primary task is to generate color and luminance signals from the bit stream it receives from the ANTIC Display Processor It also processes the Function keys provides the keyboard beep via the TV speaker and monitors controller Trigger lines Figure 1 5 is an illustration of the GTIA pin assignments 800XL Computer 1 6 Field Service Manual A n e Sn Address Sus Al 1 40 2 Address Bus Address Bus AG 2 39 A3 Address Bus Ground V SS 3 33 AS Address Bus Cata Bus D3 amp 37 08 Data Bus Data Bus D2 5 36 05 Data Bus Data Bus DI 6 35 06 Data Bus Data Bus D 7 34 D7 Data Bus Trigger 0 T 8
9. POSSIBLE CAUSES 25 45 36 O7 Lit U23 C26 29 C82 92 L19 22 U22 1723 75 79 U17 L23 L30 C96 C97 22 115 18 78 63 66 U22 REMEDY Inspect J5 6 for damaged pins replace as necessary Repair or replace Repair or replace Repair or replace Repair or replace Repair or replace Replace SECTION 4 ASSEMBLY DISASSEMBLY Disassembly Hardware Access Turn unit upside down Remove six screws from bottom cover Turn unit upright Tip cover by raising the left side allowing access to the keyboard cable Carefully disconnect the keyboard ground strap and remove the keyboard cable from its socket and lay top aside Due to incompatibility of plastic housings do not interchange top or bottom housings between units Keep the housings which belong to each unit with that unit PCB Removal Remove the four remaining screws holding the PC Board o Lift up on the front of the PC Board while pushing out on the right side of the bottom housing player port side until the player ports clear the bottom housing Remove the PC Board Assembly Reassempble in reverse order 800XL Computer 54 1 Field Service Manual SECTION 5 SCHEMATICS AND SILKSCREENS AND PARTS LIST The schematic and silkscreen for the 800XL are attached to the front cover of this manual Remove them and place this section NOTE The schematic is a domestic U K version All U K additions are shown
10. data lines DO through 07 The ROM requires a power input of 5 volts BASIC ROM The Atari 800XL has built in Atari BASIC Rev B residing in an 8K X 8 ROM This is equivalent to having an Atari BASIC cartridge permanently plugged into the console Any cartridge plugged into the computer takes precedence over the built in BASIC DRAMS The 800XL Dynamic Random Access Memories DRAMS consist of eight 64K X 1 DRAMS MEMORY MANAGEMENT UNIT MMU The memory management unit MMU address decoding circuitry consists of a PLA Programmable Logic rray LC one 3 to 8 decoder and a few gates The input to the circuitr y includes the address lines through 15 as weil as control signais such as ROM from PIA and DRAM refresh from ANTIC Some of the most important outputs of this circuitry include select signals for the GTIA POKEY PIA OS ROM DRA MS BASIC and cartridge 800XL Con ds 9 Field Service Manual RF MODULATOR The RF modulator accepts the composite video from the video summation Circuitry and the mono aural audio signals and produces a modulated signal suitable for the television With a 75 Ohm termination the modulated signal has the following characteristics Maximum Voltage 2MV Minimum Voltage Audio Sound Carrier Frequency 4 5 MHz Frequency Response Channel Z Band 6 MHz Video Carrier 55 25 MHz Audio Carrier 59 75 MHz Channel 3 Band 6 MHz Video Carrier 61 25
11. 7415375 iC Delay Module AND OR Inverter 74LS51 Resistor 1 4W 0 Ohm Socket IC 8 pin Socket IC 14 pin Socket IC 16 pin Socket IC 20 pin Socket IC 24 pin Socket IC 40 pin Crystal 3 579545 MHz Field Service Manual Part Number C012294 C015795 C014336 C014345 060619 060472 C060474 060629 014386 01 C014386 02 014386 03 C014386 05 C014 386 07 C014386 09 C061090 SECTION 6 SERVICE BULLETINS This section is to be used by you to file the three classifications of service bulletins that are periodically released by the Director of Technical Support The following are brief descriptions of each classification FIELD CHANGE ORDER A Field Change Order describes mandatory hardware or software changes to ATARI products and instructs how to implement these changes The changes must be performed on all units serviced or repaired UPGRADE BULLETIN An Upgrade Bulletin describes product improvements or modifications that the consumer may wish to purchase These bulletins allow you to modify the customer s unit to add capabilities which may not have been available when the unit was originally manufactured TECH TIP A Tech Tip is a document of a general nature which transmits routine service or repair information By communicating methods developed since you attended training classes Tech Tips aid to continuously improve repair skills and increase knowledge of ATARI products
12. 800 XL COMPUTER FIELD SERVICE MANUAL FD100740 ATARI U S CORP REV 02 JUNE 1985 ATARI 86 COMPUTER FIELD SERVICE MANUAL ee o MY Atari believes that the information described in this manual is accurate and reliable and much care has been taken in its preparation However no responsibility financial or otherwise shall be accepted for any consequences arising out of the use of this material Information contained herein is subject to change Revisions may be issued to advise of such changes and or additions Correspondence regarding this document should be forwarded to Director of Technical Support Consumer Product Service Atari Incorporated 1272 Borregas Avenue Sunnyvale California 94056 i ido MP ee Ss Section 6 800XL Computer Field Service Manual TABLE OF CONTENTS Title INTRODUCTION THEORY OF OPERATION User Interface Mechanical Theory Electrical Theory 6502C CPU Microprocessor Alphanumeric Television Interface Controller ANTIC Graphic Television Interface Adaptor GTIA Pot Keyboard Integrated Circuit POKEY Peripheral Interface Adaptor PIA Memory ROMs and DRAMs OS ROM BASIC ROM DRAMS Memory Management Unit MMU RF Modulator Monitor Output Power Supply System Interface Serial Input Output SIO Interface Keyboard Interface Controller Jack Interfaces Cart
13. ICS AND SILKSCREENS AND PARTS LIST Electrical drawings and layouts of the 800XL Printer Circuit Board and a list of the parts used o SERVICE BULLETINS Section to be used for Field Change Orders Upgrade Bulletins and Tech Tips 800XL Computer Field Service Manual SECTION 1 THEORY OF OPERATION The Atari 800XLIM 15 an enhanced version of the existing ATARI Computer Systems It can be used with any of the existing Atari peripheral devices used with the 400 1 TM 8001TM 1200XL TM Computers The PCB contains 64K of RAM an operating system that contains one 16K X 8 ROM and an on board Atari BASIC programming language LC The console contains the keyboard and four function keys including a HELP key plus a RESET key a single cartridge slot connector jack for daisy chaining peripherals and connecting hand controllers a detachable RF TV interface cable a 5 pin DIN Monitor Jack one status LED POWER and a parallel bus interface PBI USER INTERFACE The Atari 800XL is general purpose microcomputer that uses a 6502C microprocessor The 800XL console is the central processing unit for its respective system The right side panel contains the controller jacks that accept the Atari X Y joysticks and paddle controllers The rear panel contains the serial input output SIO jack the PBI the RF jack the monitor jack the channel 2 3 switch the power in jack and the power switch On Off The console has a
14. MHz Audio Carrier 65 75 MHz MONITOR OUTPUT The 5 pin DIN monitor output jack 22 accepts the composite video and the composite luminance signals from the GTIA video summation circuitry and the amplified mono aural audio signals from POKEY J2 then transfers these signals directly to the input of the video monitor via a 5 pin DIN monitor cable The output signals have the following characteristics Min Voltage Max Voltage Composite Video 750 MV P P P P Composite Luminance 1 2V 1 5V Audio 600 P P 750 Mv P P POWER SUPPLY The power supply connector is a 7 pin DIN connector The Atari 800XL has an external power supply that accepts 110 VAC nominal from the power lines and provides 5 VDC output 2 The maximum rating for the supply is 5 volts and 1 2 amps 800XL Computer 1 10 Field Service Manual Figure 1 8 is an illustration of the power supply connector pin assignments Ground Ground Figure 1 8 Power Supply Pin Assignments Looking Toward Computer SYSTEM INTERFACE The 800XL provides the following interfaces Serial input output SIO o Keyboard Interface o Controller Jacks o Cartridge Interface o Parallel Bus Interface PBI SERIAL INPUT OUTPUT SIO INTERFACE The Atari 800XL communicates with peripheral devices via an asynchronous serial port 19 2K Baud rate max Data is transmitted and received as eight bits of serial data LSB is sent first preceded by a logic zer
15. Other times Tech Tips alert vou to units that have been modified and are now standard for ATARI Manufacturing but are different from many existing units and require different repair techniques 800XL Computer 6 1 Field Service Manual
16. anual CONTROLLER JACK INTERFACES The 800XL provides two controller jack interfaces Both are functionally and electrically identical The controller jacks are 9 pin D type male connectors Figure 1 10 shows the pin assignments for the 9 pin connectors 1 Joystick Forward Input 6 Trigger Input 2 Joystick Back Input 7 5 volts 3 Joystick Left Input 8 Ground 4 Joystick Right Input 9 A Potentiometer Input 5 B Potentiometer Input Figure 1 10 Controller Jack Pin Assignments CARTRIDGE INTERFACE The cartridge interface connects cartridges to the computer with a 30 pin connector The Atari 300XL has Revision of Atari BASIC built in This is equivalent to having a BASIC cartridge permanently plugged into the console When any cartridge is plugged into the computer it takes precedence over the built in BASIC This is a function of hardware When no cartridge is plugged in the hardware enables the built in BASIC Figure 1 11 illustrates the pin assignments the cartridge connector 800XL Computer 1 13 Field Service Manual lt a 2 GND a2 4 4 1 4 D 5 Ag 15 04 6 F 7 ps 218 2149 fg 12 CONSOLE CONSOLE BOTTOM op 1 03 TOP 11 07 55 12 an 1 A10 RD5 14 R R CCNTL L152 B Z Figure 1 11 Cartridge Connector Pin Assignments 800XL Computer 1 18 Field Service Manual PARALLEL BUS INTERFACE The
17. ignments Looking into the Computer 800XL Computer Field Service Manual SECTION 2 TESTING OVERVIEW This section describes the procedures available for testing and troubleshooting the 800XL They are o Self Test SuperSALT Diagnostic Cartridge and SuperSALT Test Assembly EQUIPMENT NEEDED 800XL Computer console with accessories TV set properly adjusted SuperSALT Diagnostic Cartridge FD100335 SuperSALT Test Assembly FA1 00332 SuperSALT Technical User s Manual FD100770 90000 SELF TEST FEATURES The Self Test feature allows minimal testing of the following components o Memory RAM ROM and ANTIC o Audio Visual ANTIC GTIA and POKEY o Keyboard POKEY and ANTIC NOTE Remove any cartridge from the unit To enter the testing sequence press and hold the OPTION key while the console is turned on The Self Test menu screen will appear To exit the test press the SYSTEM RESET key the Basic Ready prompt will appear on the screen NOTE Pressing the HELP key has no effect in any situation except possible future application programs and as an exit from individual test to return to Seif Test menu Procedure 1 Connect the computer console to TV set as shown in owner s manual 2 Turn on set 3 Press and hold the OPTION key as the computer is turned on until the Self Test menu appears 4 The Self Test Menu displays four options Audio Visual
18. in dotted boxes READ the notes at the bottom left corner before any troubleshooting is performed This section contains the complete Parts List for the 800XL 800XL Computer Field Service Manual 5 1 Location Al et 79 47 11 13 94 95 5 6 8 9 12 14 15 21 46 47 50 71 78 80 92 96 97 102 112 71614 25 32 34 43 48 51 57 62 68 70 93 105 109 17 23 83 66 19 20 22 C24 50 98 Ch 800XL Computer SECTION 5 PARTS LIST Description Console Assembly Door Cartridge Dar Door Spring Door Keyboard Power Supply T V Switchbox Pkgd RF Cable PCB Assembly Cartridge Guide Shield Top Shield Bottom Modulator Domestic UM1652 Cap Elec Axial 470uF 10V Cap Elec Axial 22uF 16V Cap Ceramic Axial 01 25V Cap Ceramic Axial 001uF 50V Cap Ceramic Axial luF 25V Cap Ceramic Axial 047uF 50V Cap Nonpolarized 4 7uF 35V Cap Elec Alum 10uF 16V Cap Ceramic Axial 68pF 50V Field Service Manual Part Number C024 582 001 024630 001 028681 001 061983 028814 001 CA014746 CA024624 001 C060297 024467 001 024468 001 061619 014370 014393 014181 02 018181 01 014181 03 014180 09 C061 647 014371 014179 12 Location C45 11 3 7 9 14 5 LE L10 15 30 L14 1 5 07 08 9 R1 11 59 R2 7 52 R3 58 R4 39 R12 15 16 19 22 31 34 63 74 75 85 88 R23 30
19. issing Bar Upside down Alpha Numerics on Player Field Some Keyboard Keys Fail Ail Keyboard Kevs Fail Tone or Tones Missing During Tone Test Console Game Switches Will Not Functon ROM Test Failed RAM Test Failed Video or ANTIC Stress Fail CPU Test Fail 2 Way Clock Fail External Audio GTIA Fail POSSIBLE CAUSES Power LED Power Supply Cables Ui7 U20 U7 022 Keyboard U24 U25 Cable 1122 2 25 022 4 5MHz Ul Audio Carrier Frequency volume 017 Keyboard Cable U2 U5 U2 9 16 18 19 26 30 U7 1 08 Q9 U8 TL p J1 Ul 917 Keyboard and switch require operator intervention REMEDY Repair or Replace Repair or Replace Replace Repair or Replace Repair or Replace Repair Adjust 4 5 MHz RF Modulator Replace if necessary Repair or Replace Repair or Replace Verify ANTIC is Rev E Repair or Replace Repair or Replace Verify 3 58 MHz osc frequency Repair or Replace Repair or Replace Repair or Replace Replace Requires the SuperSALT Test Assembly jumper cables power supply for correct operation respective testing 00 Computer Field Service Manual 3 2 Joystick and Paddle Test require user action with a joystick and paddle during SYMPTOM Port Test Failures Voltage 2 Voltage MC PIA Ports SLY Port Trigger Lines POT Lines Timers 800XL Computer Field Service Manuai
20. ix tones sound and the corresponding note shows on the staff The tune plays sequentially from channel one through channel four The channel number changes for each according to the sound channel in use Voice numbers 1 4 under the staff and treble clef indicate the channel in use There is a slight pause between each voice A fault is indicated by a note appearing on the screen without any sound and vice versa The AUDIO VISUAL TEST continues testing until either the HELP or RESET key is pressed KEYBOARD TEST Purposes To test the POKEY ANTIC and ROM chips Format A full keyboard is displayed on the screen Press each keyboard key and the corresponding key on the screen changes to inverse video and a tone u t sounds It shouid change back to the original color when the key is S00XL Computer 2 2 Field Service Manual released NOTE The control and shift keys change only when pressed at the same time as another key The display for both keys will change to inverse video and then back As each key except RESET HELP amp BREAK is pressed a tone is generated ALL TESTS All of the Self Tests are executed one after another until either the HELP or RESET key is pressed NOTE When ALL TESTS is executing the MEMORY TEST and the AUDIO VISUAL TEST exit after one complete test cycle KEYBOARD TEST during ALL TESTS is software controlled No operator input is required SUPERSALT TESTING For SuperSALT testing procedures refe
21. o start bit and succeeded by a logic one stop bit serial data out is transmitted or received as positive logic The serial data out line always assumes its new state when the serial clock out line goes high Clock out goes low in the center of data out The bus protocol specifies that all commands must originate from the computer and that peripherals present data on the bus only when commanded to do so Every bus operation goes to completion before another bus operation in initiated An error detected at any point in the bus operation aborts the entire sequence A bus operation consists of the following elements 800XL Computer 1 11 Field Service Manual Command Frame From Computer Command Frame 1 Data Send 2 Data Receive 3 Immediate No Data Command Only i e status Acknowledge Frame From Peripheral Optional Data Frame To Or From Computer Complete Frame From Peripheral Figure 1 9 shows pin assignments for the SIO connector 1 Clock Input 8 Motor Control 2 Clock Output 9 Proceed 3 Data Input 10 5 Ready 4 Ground 11 Audio Input 2 Data Output 12 Not Connected 6 Ground 13 Interrupt 7 Command Figure 1 9 SIO Connector Pin Assignments KEYBOARD INTERFACE The keyboard has 55 alphanumeric keys including specia characters and controls a spacebar which interface thru U24 and U25 Keyboard Sense Scan Decoders four function keys and a RESET key SOOXL Computer 1 12 Field Service M
22. purpose Input Output 1 chip It monitors the X Y controller interfaces and the SIO control lines In certain applications it may control the MMU logic Figure 1 7 is an illustration of the PIA assignments 800XL Computer 1 8 Field Service Manual Ground vss i fj Control Line Controller Input zag 1 Motor Controli Output emme Interrupt Request Cutputi 953 Interrupt Request Output f Al Address Line 3 Address Line an Reset Input Controller Input Controller Input 282 Controller Input Controller Input 7A Controller Input 43 Controller Input Ab Data Line Controller Input Data Line Enable Disable Output Data Line Not Used 23 Data Line Cutput To Led 1 pas Data Line Not Used pas 23 Data Line Not Used 7 Data Line Not Used C Data Line Not Used Pas dL 02 Ciock Input Self Test Output Lj c Chip Select Input Control Line Ciis 4 lt lt Chip Select Input Command Output 999 1 4 lt SF Chip Select Clock Input Supply Voltage 0 Ui jes vY Read Write 5 Volts Figure 1 7 PIA Pin Assignments MEMORY ROMS AND DRAMS 5 ROM The 800XL operating system is resident in one 16K X 8 ROM The ROM address inputs are from CPU address lines AO through A13 The chip selects from the address decoding circuitry and generates data on CPU
23. r to SuperSALT Technical User s Manual P N FD100770 800XL Computer 2 3 Field Service Manual SECTION 3 SYMPTOM CHECKLIST The Symptom Checklist is designed to aid the technician in arriving at listed in the order of failure rapid diagnosis of problems Each symptom is accompanied by some possible causes and suggested remedies manuai SYMPTOM Snowy Screen Black Grey Screen Red Brown Blue screen Yellow screen No Color or Bad Color 800XL Computer Field Service Manual POSSIBLE CAUSES TV Switch Box ON OFF switch Channel Select switch RF Modulator Defective Power Supply Damaged RF Cable Defective open components on 5C line Defective shorted components on 5A B and or C lines Defective shorted LSI s and or IC s Y1 Q8 9 C109 72 7 20 22 23 26 30 U2 5 18 19 28 30 02 023 RF Modulator R38 17 020 O1 O3 CR2 3 1 Instructions for disassembly assembly are SECTION 4 of this REMEDY Adjust or replace Replace Isolate and replace Isolate and replace Isolate and repair Troubleshoot the clock circuit and replace defective component isolate and replace defective IC Isolate and replace defective IC Replace Replace Adjust or replace Troubleshoot color video circuitry Replace de fective IC component Verify 3 579545 MHz freq of Yl Replace if defective SYMPTOM No Power Light 11 No Gray Bars or M
24. ressing modes o True indexing Stack pointer Two interrupt levels 64K address range Integral clock circuit Single 5 volt DC power requirement Figure 1 3 is an illustration of the 6502C CPU Pin Assingments 800XL Computer 1 4 Field Service Manual Ground RDY Input asy Phase 1 Clock Interrupt Request Ug NIC Non Maskable Input ar PEL 5V POWER SS Address Bus 9 Address Bus Address Bus Address Bus Address Bus Address Bus Address Bus Address Bus Address Bus Address Bus Address Bus aig 5 5 8 C Address Bus Figure 1 3 6502C CPU Pin Assignments phanumeric Television Interface Controller ANTIC 6502C MODIFIED 23 2 RSEN res Reset A Phase 2 Clock 59 Overflow Phase 0 Clock 2 9 Read Write HALT HALT Input 2 Bus a Data Bus o2 Data Bus 03 Data Bus Data Bus 233 Bus Bus a Bata Bus 1 Address Bus ais Address Bus Address Bus 1 Address Bus vss Ground The ANTIC Display Processor is a custom display microprocessor with an instruction set customized for graphics generation control the ADDRESS amp DATA bus and RAM Refresh It also has the ability to Figure 1 4 is an illustration of the ANTIC Display Processor pin assignments 800XL Computer Field Service Manual GROUND 55 1 0 Data Sus Alphanum Data ANS 2 DS Data
25. ridge Interface Parallel Bus Interface TESTING Overview Equipment Needed Self Test Features Description of Self Tests Memory Test Audio Visual Test Keyboard Test All Tests SuperSALT Testing SYMPTOM CHECKLIST ASSEMBLY DISASSEMBLY SCHEMATICS AND SILKSCREENS AND PARTS LIST Parts List SERVICE BULLETINS ili NNN NN NN ND Page i WW UJ NJ NN rm i Re 2 1 5 3 6 1 800XL Computer Field Service Manual TABLE OF CONTENTS LIST OF ILLUSTRATIONS Title System Block Diagram Functional Block Diagram 6502C CPU Pin Assignments ANTIC Display Processor Pin Assignments GTIA Pin Assignments POKEY Pin Assignments PIA Pin Assignments Power Supply Pin Assignments SIO Connector Pin Assignments Controller Jack Pin Assignments Cartridge Connector Pin Assignments PBI Connector Pin Assignments iv INTRODUCTION The Atari 800 1 Computer Field Service Manual is a reference guide for the service technician The Field Service Manual is organized into six sections o THEORY OF OPERATION Overview of how the 800XL works and what its basic assemblies look like o TESTING Review of Diagnostic tests available for diagnosing 800XL problems o SYMPTOM CHECKLIST Failure information to aid the technician for a rapid diagnosis 800XL problems o ASSEMBLY DISASSEMBLY Assembly Disassembly instructions o SCHEMAT
26. ss 64K memory locations The eight line data bus provides the communication and data path between the functional modules The power is provided by an external power supply and routed throughout the console To Atari Cartridge Cartridge Interface Operating System ROMs System Memory DRAMs 800XL Computer Field Service Manual To Joysticks Paddles Etc Controller Ports Parailei Bus Interface To Disks Printers Cassettes Etc 1 O Processing Circuitry Pokey PIA and SIO Miscellaneous Interfaces Circuitry Keyboard with Function keys and LEDs Display Processing Circuitry ANTIC GTIA and Miscellaneous Circuitry RF To Television Modulator Monitor Jack To Monitor Figure 1 1 System Block Diagram 1 2 The keyboard connects to the PC Board by a 24 connector ribbon cable The keyboard is the user interface with the computer All peripherals connect to the 800XL either through the SIO connector or the PBI Power enters through the 7 Pin DIN connector on the rear panel RF to the TV switchbox arrives from an RCA phono connector and RF cable Composite Video composite luminance and audio signals to the monitor arrive from a 5 pin DIN monitor jack on the rear panel Power On Off is controlled by the ON OFF switch on the rear panel Cartridge Interface i TRI CP LI CECI j 4
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