Atari 800 Field Service Manual

800 COLOR
BAA
TROUBLESHOOTING
(cont
)
Verify that
each of
the following levels
and/or
signal wave
forms exist
before proceeding
to
the
next step.
Use SALT II.
COLOR
BARS,
locked
into the
continuous mode.
Is there
3.3SMHX NO
Swap-out
XlOl,
Q102
and
O103
oscillation at
R106
on Motherboard
Refer Figure
NO
YES
Is there
input
signal to base
of
QI05, Pin
2 Refer
Figure
Trace
circuit
back
to
previous
step
NO
YES
Is there
output
signal
from emitter
of
Q105 Refer
Figure
Trace
circuit
back to
previous step
NO
YES
Is there
signal at
JH5, Pin
20
Refer
Figure
Trace
circuit back
YES
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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