Atari 800XL Service Manual

SYMPTOM
POSSIBLE CAUSES
SOLUTION
CPU
Test
Fail
Y1
,Q8,Q9,
U8
Yerify
3.58
MHz
osc.
frequency;
repair
or
replace.
RAM
Test
Failed
U2,
U3,
U9-16,
U18,
U19,
U26-30
Yerify
ANTIC
is
Rev E.
•
repair
or
replace.
ROM
Test
Failed
U2-U5
Repair
or
replace
Video
or
ANTIC
Stress
Fail
U7
Repair
or
replace
GTIA
Fail
U17
Replace
No Power
Light
(LI)
Power
LED,
Power
Supply,
Cables
Repair
or
replace
Console
Came
Switches
Will
Not
Function
U17,
Keyboard,
Cable
Repair
or
replace
Tone
or
Tones
Missing
During
Tone
Test
U22.4.5
MHz.UI,
Audio
Carrier
Frequency,
TY
volume
Repair,
adjust
4.5
MHz
on RF
Modulator;
replace
if
necessary.
No
Gray
Bars
or
Missing
Bar
U17.U20
Repair
or
replace
Upside
Down
Alpha/
Numerics
on
Player
Field
U7
Replace
Some
Keyboard
Keys
Fail*
U22,
Keyboard,
U24,
U2S,
Cable
Repair
or
replace
All
Keyboard
Keys
Fail
U22,
U24,
U25
Repair
or
replace
2-Way
Clock
Fail**
J1.U22
Repair
or
replace
External
Audio**
J1.U1
Repair
or
replace
*
Keyboard
and
switch
require
operator
intervention.
**
Requires
the
SuperSALT
Test
Assembly
,
jumper
cables,
power
supply
for
correct
operation.
Joystick
and
Paddle
Test
require
user
action
with
a
joystick
aid
paddle
during
respective
testing.
29

Atari 800XL Specifications

General

Manufacturer	Atari
Type	Home computer
Release year	1983
CPU	MOS Technology 6502C
RAM	64 KB
ROM	24 KB
Operating System	Atari OS
CPU Speed	1.79 MHz (NTSC) / 1.77 MHz (PAL)
Graphics	ANTIC and GTIA chips
Display resolution	160×192 to 320×192 pixels
Sound	POKEY chip
Storage	Cassette tape, floppy disk
Ports	Serial, parallel, monitor, joystick ports