Atari 800 Service Manual

Table 5-1. Troubleshooting Guide
Description Possible failure Test
Procedure
MEMO PAD TEST
• Green Screen
• Black Screen
• Random Characters on
Screen
• Unit Locks Up
• Character begin scrolling
across screen
Loose or dirty
contacts with RAM
or CPU boards
Motherboard
1
2
VISUAL INSPECTION
• Damaged or bent pins
• Cover Closed switch will
not work properly
• RF Cable cut or badly
damaged
• Bare or pinched area on
RF cable
Replace damaged
board
Plunger or Power
Supply
Replace RF Cable
Replace RF Cable
2
2
Replace
immediately
Replace
immediately
KEYBOARD TEST
• Key depressed not
displayed
• Key depressed not same
key that appeaes on
screen
• Characters begin
scrolling across screen
Motherboard
Or
Keyboard
2
STAND ALONE TEST
• System Error (can not
power-up with Stand Alone
Test Cartridge inserted)
• Fails Any Video Test
• Fails Color Bar test
• Fails Gray Bar test
Cartridge Guide
RAM Memory Board
CPU Board
2
2

Atari 800 Specifications

General

Processor	MOS Technology 6502
Processor Speed	1.79 MHz
ROM	10 KB
Graphics	ANTIC and GTIA chips
Release Year	1979
Display Resolution	up to 320 x 192
Colors	128 colors
Sound	4 channels
Storage	Cartridge, cassette, floppy disk
Ports	Cartridge, serial, monitor
Operating System	Atari OS