Atari 400 Quick start guide

ATARI HOME COMPUTER
FIELD SERVICE MANUAL
40/S

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 Manager of Technical
Support, Consumer Product Service, ATARI, Incorporated, 1312 Grossman Road,
Sunnyvale, CA 94086, U.S. America.

TABLE OF CONTENTS
Section Title Page
INTRODUCTION ix
1THEORY OF OPERATION l-I
Overview l-l
User Interface 1-2
*00/S00 Mechanical Description 1-3
Motherboard 1-4
Central Processing Unit 1-5
ROM Personality PCB 1-5
RAM PCB 1-5
Keyboard 1-6
Power Supply 1-6
Program Cartridge 1-6
*00/800 Electronic Discussion 1-7
Central Processing Unit 1-7
CPU 6502 Integrated Circuit 1-7
Alphanumerical Television 1-S
Interface Controller
Color Television Interface 1-10
Adaptor
Grcphic Television Interface 1-10
Adaptor
I/O Decoder 1-10
Composite Video 1-10
Motherboard Console -*00 l-l 1
Pot Keyboard Integrated 1-11
Peripheral Interface Adaptor I-1
1
Key-In Key-Out Integrated 1-12
Circuit
Memory Map Decoder 1-12
I/O Decoder 1-13
Motherboard Console -800 1-U
Bi-directional Data Buffer l-U
ROM Personality Board 1-15
Power Supply 1-16
ROM Cartridge 1-17
Accessories 1-17
AC Power Adaptor 1-17
TV Switch Box 1-17
'BASIC Program Cartridge 1-17
2SILKSCREEN AND SCHEMATICS 2-1
3TROUBLESHOOTING AND TESTING 3-1
Overview 3-1
Tests ^3-1
Equipment Needed 3-1
Testing With and Without 3-2
the SALT II Cartridge
ATARI Home Computer iii

TABLE OF CONTENTS (Cont)
Section Title Page
Overview of Tests 3-2
Power-Up Test 3-2
Keyboard Test 3-2
RAM and ROM Test 3-2
SALT nMenu 3-5
Color Bar Test 3-6
Any Video Test 3-7
Gray Bar Test 3-S
Keyboard Test ,. . .»3-9
Switch Test 3-9
Tone Test 3-9
Display Options 3-10
Port Test 3-10
Verify ROM Test =3-11
RAM Test 3-12
MTest ...-•. 3-15
Star Raider Test 3-16
Shake Test 3-16
Bumin 3-16
Description of the Other Functions 3-17
Production Test 3-17
Boot B3-17
Examine 3-17
Adjust 3-17
Summary 3«1
7
if DISASSEMBLY/ASSEMBLY MAINTENANCE i^-i
ATARI *00 Home Computer Console -Disassembly .»..,.. ^1
Keyboard and Power Supply Access «if-1
Keyboard Removal if-3
Power Supply Removal ti~4
CPU, RAM and Motherboard Access ^6
CPU and RAM Removal if-6
ATARI 800 Home Computer Console -Disassembly ^-S
Access to RAM Boards and if-S
ROM Board
Access to Power Supply and ^9
Keyboard Assembly
Remove Top Cover if-9
Remove the PCB Module ^-10
Remove the Power Supply „..i^-i 1
Access to CPU Printed Circuit Board if-1
2
Access to Motherboard ^-13
Keyboard Removal i^-l /f
ATARI Home Computer iv

TABLE OF CONTENTS (Cont)
Section Title Page
ATARI WO Home Computer Console -Assembly ^15
Module Assembly Reassembly it~l5
Keyboard Installation *-I6
Power Supply Installation ^^-16
Top Cover Installation i^-17
ATARI 800 Home Computer Console -Asc^mbly H~i7
Keyboard Assembly ^17
Motherboard Installation ,i^-^7
CPU PCB Installation i^-lS
Power Supply Installation *-l 8
Module Assembly Installation Into Top Cover *-19
Bottom Cover Installation t^iS
RAM and ROM Installation *-20
Cartridge Door Assembly f^-20
PCB Contact Cleaning and Lubricating ^20
Tools Required i^-20
Procedure ^21
Visual Inspection f^-21
5WO DIAGNOSTIC FLOWCHARTS 5-1
6WQ/800 SYMPTOM CHECKLIST 6-1
7800 DIAGOSTIC FLOWCHARTS 7-1
8GAME CONTROLLERS 8-1
Joystick (X-Y Controller) S-i
Joystick (X-Y ControUer) Check 8-3
Equipment Needed 8-3
Procedure 8-3
Game Paddle 8-4
Game Paddle Controller Check 8-5
Equipment Needed 8-5
Procedure 8-5
9PARTS LIST g.l
*00 Computer 9-2
800 Computer 9_7
10 SERVICE BULLETINS lO-l
ATARI Home Computer

LIST OF ILLUSTRATION
Figure Title "Page
1-1 ATARI *00 Home Computer Console 1-1
1-2 ATARI 800 Home Computer Console 1-2
1-3 MPU Pin Assignments 1-8
i-4 ANTIC Pin Assignments 1-9
1-5 CTIA/GTIA Pin Assignments 1-10
1-6 POKEY Pin Assignments l-ll
1-7 PIA Pin Assignments 1-12
1-8 WO Motherboard Flow Diagram 1-18
1-9 *00 Power Supply 1-19
I-IO 800 Motherboard Flow Diagram 1-20
1-1
1
800 Power Supply Flow Diagram 1-21
1-12 800 Personality Board 1-22
1-13 CPU Board Flow Diagram 1-23
I-U 8K Dynamic RAM Flow Diagram 1-2^
1-15 16K Dynamic RAM Flow Diagram 1-25
1-1
6
Game Cartridge Flow Diagram 1-26
1-17 ATARI Home Computer System 1-27
Block Diagram
2-1 WO Motherboard Siikscreen 2-3
2-2 *00 Motherboard Schematic 2-4
2-3 400 Power Supply Siikscreen 2-6
2-^ *00 Power Supply Schematic 2-7
2-5 800 Motherboard Siikscreen 2-9
2-6 300 Motherboard Schematic 2-10
2-7 800 Power Supply Siikscreen 2-12
2-8 800 Power Supply Schematic 2-13
2-9 800 Personality Board Siikscreen 2-U
2-10 800 Personality Board Schematic 2-15
2-1
1
CPU Board Siikscreen 2-16
2-12 CPU Board Schematic 2-17
2-13 8K RAM Board Siikscreen 2-18
2-U 8K RAM Board Schematic 2-19
2-15 16K RAM Board Siikscreen 2-20
2-16 16K RAM Board Schematic 2-21
3-1 Special Graphics Test 3-3
3-2 SALT Header 3-/*
3-3 SALT II Menu 3-5
3-A Color Bar Test Screen 3-6
3-5 Any Video Test Screen 3-7
3-6 Gray Bar Test Screen 3-8
3-7 Port Test Screen 3-10
3-8 RAM TEST Screen 3-13
ATARI Home Computer vi

LIST OF ILLUSTRATION (Cont)
Figure Title Page
*-l ATARI *00 Console, Bottom Cover Screw Location *-2
^-2 ATARI *00 Console, Top Cover Removal *-3
*-3 ATARI *00 Console, Keyiaoard Removal *-4
*-* ATARI *00 Console, Power Supply Removal ^5
*-5 ATARI *00 Console, Module Assembly *-7
*-6 ATARI 800 Console, Cartridge Door -*-9
Assembly Removal
^'7 ATARI 800 Console, Bottom Cover Removal i^-10
if-S ATARI 800 Console, Module Assembly Removal *-l 1
*-9 ATARI 800 Console, Power Supply Removal (^-12
if-lO ATARI 300 Console, CPU Printed Circuit -*-13
Board Removal
'f-l 1ATARI 800 Console, Motherboard Removal ^--15
*-12 ATARI 800 Console, Keyboard Removal ifr-l5
5-1 Keyboard Connection Chart 5-38
5-2 Defective RAM Boards 5-39
7-1 Keyboard Connection Chart 7-38
7-2 Defective RAM Boards 7-39
8-1 Joystick (X-Y ControUer) 8-2
8-2 Joystick Schematic 8-3
8-3 Game Paddle 8-4
8-4 Game Paddle Schematic 8-5
LIST OF TABLES
Table Title Page
1-I Memory Map Selected Lines 1-13
1-2 I/O Decoder Select Line 1-14
3-1 Port Test Legend 3-12
3-2 Defective RAM Boards 3-U
3-3 Defective RAM Identified 3-15
5-1 Clock Circuit 5-36
5-2 Defective RAM Boards 5-39
5-3 Port Test Legend 5-40
7-1 Clock Circuit 7-36
7-2 Defective RAM Boards 7-39
7-3 Port Test Legend 7-40
ATARI Home Computer vii

INTRODUCTION
The ATARI ^00/800 Home Computer"^^ Field Service Manual is organized in 10
Sections:
iTHEORY OF OPERATION -overview of how the *00 and 800 Home
Computers work-
2SILK5CREEN5 AND SCHEMATICS -electrical layouts and drawings for
major components.
3TESTING AND TROUBLESHOOTING -overview of tests which assist in
diagnosing malfunctions.
*DISASSEMBLY/ASSEMBLY -detaUed instructions to completely
disassemble and assemble both units.
5WO DIAGNOSTIC FLOWCHARTS -detailed procedures for
troubleshooting and repairing the *00 Computer.
6*00/800 SYMPTOM CHECKLIST -quick reference for troubleshooting
each computer.
7800 DIAGNOSTIC FLOWCHART -detailed procedures for
troubleshooting and repairing the 800 Computer.
8GAME CONTROLLERS -overview of hand controller construction and
recommended test procedures.
9PARTS LIST -detailed breakdown of all parts used in each unit.
10 SERVICE BULLETINS -section to be used to hold Field Change Orders,
Upgrade Bulletins, and Tech Tips.
This manual is designed for use by both the experienced and inexperienced service
technician. The Diagnostic Flowcharts (Sections 5and 7) provide detailed
diagnostics and repair procedures for technicians not completely familiar with the
ATARI *00/800 Home Computers. The Symptom Checklist (Section 6) provides a
rapid repair reference for the more experienced technician.
ATARI Home Computer ix

SECTION I
THEORY OF OPERATION
OVERVIEV
The Atari *00 Computer Home Console contains the central processor unit (CPU) and
memory in the form of the Operating System (read-only-memory (ROM)) and 8K or
16K of user programmable random access memory (RAM). The console contains the
keyboard, cartridge slot, controller jacks, and serial input/output (I/O) port for
connecting peripheral devices (see Figure l-U.
rawci
oNforr
SWITCH
KiirmsAL
CONNECTOa
JACK
SYSTIM RESET
SWITCH
Figure 1-1. ATARI ^00 Home Computer Console
ATARI Home Computers 1-1

The ATARI 800 Home Computer Console contains the CPU and memory in the form of
the Operating System (iOK of read-only-memory (ROM)) and SK to i6K (standard) of
user programmable random access memory (RAM); plus two expansion sockets for
additional RAM modules (maximum ^8K). The console also contains the keyboard,
cartridge slots (2), controller jacks and aserial I/O port for connecting peripheral
devices (see Figure 1-2).
HAND
CONTtOUn
tACKS
SYSTEM HSCT
SWITCM
Figure 1-2. ATARI 800 Home Computer Console
USER INTERFACE
The ATARI *00/8G0 Home Computer Consoles are general purpose microcomputers
using the 6502 microprocessor. The ATARI i^OO/800 Consoles are the central
processing units for their respective systems. Each console comes standard with a
built-in typewriter style keyboard, 8K/16K of RAM, ROM operating systems,
connector jacks for adding peripherals and hand controllers, and a15-foot Radio
Frequency (RF) cable for connection to the user's television set.
The controller jacks on the front of both consoles accepts the X-Y (joystick) and
paddle hand controllers available from ATARI.
ATARI Home Computers 1-2