Atari 1200 XL Field Service Manual Download Page 5

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INTRODUCTION

The Atari 1200XL Computer Field Service Manual is a reference guide for the service
technician.
This Field Service Manual is organized in six sections:

•

THEORY OF OPERATION - Overview of how the 1200XL works and what its basic
assemblies look like.

•

SCHEMATICS AND SILKSCREENS - Electrical drawings and layouts of the 1200XL
printed circuit board.

•

TESTING - Review of Diagnostic Tests available for diagnosing 1200XL problems.

•

SYMPTOM CHECKLIST - Failure information to assist the experienced technician
arrive at a rapid diagnosis of 1200XL pcoblems.

•

PARTS LIST - Detailed breakdown of all parts used in the 1200XL.

•

SERVICE BULLETINS - Section to be used to hold Field Change Orders, Upgrade
Bulletins and Tech Tips.

1200XL Home Computer

Field Service Manual

Summary of Contents for 1200 XL

Page 1: ...Printed in U S America Atari Incorporated FD100217 February 1983 Rev by jer eightbitter 2014 ...

Page 2: ...therwise shall be accepted for any consequences arising out of the use of this material Information contained herein I subject to change Revisions may be issued to advise of such changes and or additions Correspondence regarding this document should be forwarded to Manager of Technical Support Consumer Product Service Atari Incorporated 845 W Maude Avenue Sunnyvale CA 94086 ...

Page 3: ...anagement Unit MMU 1 11 RF Modulator 1 11 Power Supply 1 11 System Interface 1 11 Serial Input Output SIO Interface 1 12 Keyboard Interface 1 13 Controller Jack Interface 1 14 Cartridge Interface 1 15 Monitor Interface 1 16 LED Board Interface I 16 2 SCHEMATICS AND SILKSCREENS 2 1 Drawings 2 2 to 2 12 3 TESTING 3 1 Overview 3 1 Equipment Needed 3 1 Self Test 3 1 MEMORY TEST Screen 3 2 AUDIO VISUAL...

Page 4: ... Modified CPU Pin Assignments 1 6 1 5 ANTIC Display Processor Pin Assignments 1 7 1 6 GTIA Pin Assignments 1 8 1 7 POKEY Pin Assignments 1 9 1 8 PIA Pin Assignments 1 10 1 9 SIO Interface Pin Assignments 1 13 1 10 Keyboard Interface Pin Assignments 1 13 1 11 Controller Jack Interface Pin Assignments 1 14 1 12 Monitor Interface Pin Assignments 1 14 1 13 Cartridge Interface Pin Assignments 1 15 3 1 ...

Page 5: ...SCREENS Electrical drawings and layouts of the 1200XL printed circuit board TESTING Review of Diagnostic Tests available for diagnosing 1200XL problems SYMPTOM CHECKLIST Failure information to assist the experienced technician arrive at a rapid diagnosis of 1200XL pcoblems PARTS LIST Detailed breakdown of all parts used in the 1200XL SERVICE BULLETINS Section to be used to hold Field Change Orders...

Page 6: ...nsole contains 64K of RAM and has an operating system which contains two 8K X 8 ROMs The console also contains the keyboard with a HELP key four application function keys a single cartridge slot connector jacks for adding peripherals and hand controllers a detachable RF TV interface cable and three status LED s Use Figures 1 1 and 1 2 as reference for the following discussion Figure 1 1 1200XL Lef...

Page 7: ...lers available from Atari The rear panel refer to Figure 2 1 contains the Serial Input Output I O jack the RF cable jack the monitor jack the channel 2 3 switch and the Power Jack The console has a full stroke 54 key alphanumeric keyboard which includes special characters and controls a space bar three LED indicators and 11 function keys The 11 function keys above the keyboard are made of brushed ...

Page 8: ...on The 1200XL 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 ROM Operating System and power supply and includes all functions except for the keyboard and LED display The motherboard uses a common address bus data bus and clock lines The sixteen line address bus a...

Page 9: ...Figure 1 3 1200XL Functional Block Diagram 1200XL Home Computer Field Service Manual 1 4 ...

Page 10: ...y Line 6502 modified CPU Microprocessor The 6502 modified CPU microprocessor contalns register flags interconnections arithmetic logic control logic and all recognized operation codes The characteristics of the microprocessor are Byte oriented structure 151 opcodes Decimal and binary arithmetic modes Seven addressing modes True indexing Stack pointer Two interrupt levels 64K address range Integral...

Page 11: ... Processor The ANTIC Display Processor is a custom display microprocessor with an instruction set customized for graphics generation It also has the ability to control bus and RAM REFRESH Figure 1 5 is an illustration of the ANTIC Display Processor pin assignmens 1200XL Home Computer Field Service Manual 1 6 ...

Page 12: ...NTIC 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 display information bit stream it receives from the ANTIC Display Processor Figure 1 6 is an illustration of the GTIA pin assignmens 1200XL Home Computer Field Service Manual 1 7 ...

Page 13: ...he POKEY is a Custom Large Scale Integrated Circuit LSI chip It is used for audio generation Serial Input Output SIO control controller interface scan and keyboard scan Figure 1 7 is an illustration of the POKEY pin assignmens 1200XL Home Computer Field Service Manual 1 8 ...

Page 14: ... 6 POKEY pin assignments Peripheral Interface Adaptor PIA The PIA is a general purpose Input Output I O chip Figure 1 7 is an illustration of the PIA pin assignmens 1200XL Home Computer Field Service Manual 1 9 ...

Page 15: ...Figure 1 8 PIA pin assignments 1200XL Home Computer Field Service Manual 1 10 ...

Page 16: ...gnal suitable for the television The modulated signal will have the following characteristics with a 75Ω termination Maximum Voltage 2 mV Minimum Voltage 1 mV Audio Sound Carrier Frequency 4 5 MHz Frequency Response Ch 3 61 25 MHz 0 5 Ch 2 55 25 MHz Power Supply The 1200XL has a linear power supply The power supply electronics is resident on the motherboard The power supply accepts a 9VAC input th...

Page 17: ...he 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 is initiated no overlap An error detected at any point in the bus operation will abort the entire sequence A bus operation consists of the following elements Command Frame From Comp...

Page 18: ... 12 12 VDC Not used on 1200XL 13 Interrupt Figure 1 9 SIO Interface Pin Assignments looking into jack on unit Keyboard Interface Figure 1 10 is an illustration of the keyboard interface pin assignments The 1200XL keyboard uses a 15 pin Molex Connector which provides inputs to POKEY GTIA SO S1 S2 and CPU Reset Figure 1 10 Keyboard Interface Pin Assignments 1200XL Home Computer Field Service Manual ...

Page 19: ...stick Forward Input 6 Trigger Input 2 Joystick Back Input 7 5 volts 3 Joystick Left Input 8 Ground 4 Joystick Right Input 9 Pot A Input 5 Pot B Input Figure 1 11 Controller Jack Pin Assignments from left side of 1200XL Monitor Interface The Monitor Interface is a 5 pin DIN connector Figure 1 12 is an illustration of the monitor interface pin assignments Figure 1 12 The Monitor Interface pin assgnm...

Page 20: ...ge interface is a 30 pin edge connector Figure 1 13 is an illustration of the cartridge interface pin assignments Figure 1 13 Cartridge Interface Pin Assignments from left side of 1200XL 1200XL Home Computer Field Service Manual 1 15 ...

Page 21: ... manual but due to the poor condition of copies have been redesigned and presented in this chapter Minor variations in design may be encountered depending upon the production date of the console Showed below drawings provide all details required for an in depth understanding of the 1200XL 1200XL Home Computer Field Service Manual 2 1 ...

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Page 33: ...Keyboard POKEY and ANTIC To enter the testing sequence press the HELP key while the power on logo is on the screen NOTE No cartridge should be inserted in the unit To exit the test press the SYSTEM RESET key causes the power on initialization sequence or the HELP key exits back to the Self Test Screen Menu NOTE Pressing the HELP key has no effect while the HELP Self Test screen is displayed Proced...

Page 34: ...od 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 remains red and is not tested again on subsequent test passes During the RAM test the LEDs cycle one on and one off On exiting the Memory tests the LEDs will be left in the off state The Memory Test loops and continues testing until either...

Page 35: ...ote when pressed ALL TESTS All of the Self Tests are continuously 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 a complete test cycle Keyboard Test during All Tests is software controlled No operator input is required USING THE SALT 2 05 DIAGNOSTIC CARTRIDGE NOTE Not all of the tests av...

Page 36: ...the SALT Menu See Figure 3 2 The highlighted character in red on the display is the command letter for each test Press the command letter then RETURN to select a test Figure 3 2 SALT Menu A number of tests on this menu are not applicable to the 1200XL and should be disregarded They are 1200XL Home Computer Field Service Manual 3 4 ...

Page 37: ...on of what your television display screen should look like Reference gray bar Same color rabov Figure 3 3 Color Bar Test Screen A 15 color rainbow scale is displayed above the reference bar with a single color bar below The color bars directly above and below the reference bar should be the same color golden rod If not proper adjustment of VR1 makes the color bars above and below the reference bar...

Page 38: ... white representation of a colored screen The screen should have a black background with eight vertical bars Half of the vertical bars should be narrow and the other half rnuch wider A horizontal bar should appear across he top of the screen From the left to right the shade of color on the horizontal bar should change On the right of the bar two Vs should be displayed right side up one in normal v...

Page 39: ...e steady and unchanging These lines may have minor glitches at their edges A thin white line should always appear just over the top black bar No color should appear anywhere on the screen The areas above the top black bar and below the bottom white bar are of no importance to this test This test should be left on for at least 60 seconds to ensure that there is no flashing of color or shifting of t...

Page 40: ...o activate this test Figure 3 6 illustrates the RAM test screen display when command letter E is pressed under Display Options The four digit number in white at the bottom right of the screen indicates the number of tests completed A red four digit number directly above this is used to count the number of failures Failures appear as red 1 s in this display Error Counter Test Counter Figure 3 7 RAM...

Page 41: ...Defective RAM Identifier Bad Bit Column Chip No D0 U9 D1 U8 D2 U6 D3 U5 D4 U4 D5 U3 D6 U2 D7 U1 1200XL Home Computer Field Service Manual 3 9 ...

Page 42: ...ars VR1 Adjust U20 U2 U19 Q3 Y1 RF Modulator Adjust or replace VR1 Adjust Page4 2 RF Modu lator Adjust Page 4 4 No Color Bars on TIA test U19 Replace No Lights L1 L2 L3 LED 3 LED Pin 1 5A Power Supply U23 Q9 Q10 Pin 3 Pin 4 Replace If problem is LED replace the LED Board No Gray Bars RF Modulator Y1 VR1 Q3 U19 Adjust or replace VR1 Adjust Page4 2 RF Modu lator Adjust Page 4 4 Upside down Alphanume...

Page 43: ...Figure 4 1 1200XL and RF Shield 1200XL Home Computer Field Service Manual 4 2 ...

Page 44: ...e the fish paper Take care that PCB is not damaged CONSOLE ASSEMBLY 1 Position the top shield upside down on the bench 2 Position the PCB upside down on the top shield 3 Place the fish paper inside of bottom shield 4 Hold the fish paper and bottom shield together and position upside down on top of PCB Be sure that adjustment holes are clear 5 Place one push rivet in a hole in the bottom shield Rep...

Page 45: ...oard connector and the LED connector Be careful not to twist the LED connector cable RF MODULATOR ADJUSTMENT 1 Disassemble the console See Page 4 3 2 Remove the RF Shield 3 Adjust RF modulator for correct Color Bar Test Screen See Page 3 5 Figure 3 3 4 Replace the RF Shield NOTE RF modulator may also be adjusted using a frequency meter Procedure Connect the frequency meter to the RF output jack on...

Page 46: ...ED C060944 Top Label Nameplate C061071 Top Keyboard Assy CA060046 Top Indicator PC Board Assy CA060568 Top Connector Cable Assy CA060606 LED1 3 LED Pilot Lamp C014776 PCB RFI SHIELD ASSEMBLY CA061074 Main Fasterner Latching Heatsink C014796 Main Fastener Latching C015344 Main Cartridge Guide C060097 Main Conn Retainer C060098 Main Upper CPU Shield C060285 Main Lower CPU Shield C060286 Main Conn Ed...

Page 47: ...102 155 C42 47 Cap Ceramic Axial 0 1μF 25V C014181 02 C60 118 Cap Ceramic Axial 100pF 25V C014179 19 C61 Cap Ceramic Axial 150pF 25V C014179 09 C63 Cap Ceramic Axial 390pF 25V C014180 10 C96 97 Cap 820pF 25V C061336 03 C115 162 Cap Alum Elect Axial 10μF 16V C014371 C116 Cap Ceramic Axial 6800pF 25V C014180 12 C117 Cap Ceramic Axial 1500pF 25V C014180 15 C119 Cap 3 9pF 25V C061336 01 CR1 2 6 16 21 ...

Page 48: ... Resistor 1 4W 1k Ω 14 5102 101 102 142 184 185 R17 31 129 134 Resistor 1 4W 10kΩ 14 5103 148 177 _ R21 107 151 183 Resistor 1 4W 2 2k Ω i4 5222 R22 Resistor 1 4W 4 3k Ω 14 5432 R23 24 153 180 Resistor 1 4W 180Ω 14 5181 R25 28 Resistor 1 4W 130Ω 14 5131 R29 173 181 Resistor 1 4W 3 3k Ω 14 5332 R34 37 139 150 Resistor 1 4W 1 8k Ω 14 5182 R38 42 50 51 53 55 Resistor 1 4W 4 7k Ω 14 5472 57 58 84 152 ...

Page 49: ...17097 U18 IC Decoder 74LS138 C014344 U19 IC GTIA C014805 U20 IC ANTIC C012296 U21 IC 6502 Modified C014806 Ć122 IC DDU 4 14 pin C060472 U23 IC PIA C014795 U24 IC POKEY C012294 U25 IC 74I S51 C060474 U27 IC HEX CMOS Buffer CD4050B C010816 VR1 Resistor Variable 500k Ω 19 411504 W1 6 9 R44 Jumper 0Ω C060629 XU1 11 18 27 Socket IC 16 pin C014386 03 XU12 13 Socket IC 24 pin C014386 07 Alternate listed ...

Page 50: ...IN An Upgrade Bulletin describes product improvements or modifications which 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 deve...

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