Commodore 128 - Trouble-Shooting Chart

TROUBLE-SHOOTING CHART
Symptom
Indicator light not 'ON'
No picture (Monitor)
No picture (TV)
Random pattern on screen
with cartridge
in place
Cause
computer not turned ON
Power supply not plugged
into computer
Power supply not plugged
into mains power supply
Bad fuse
in power supply
Monitor not connected
40 / 80 column setting
incorrect
I ncorrect connection
Cable
to TV not
plugged
in
Computer and / or TV set
for wrong channel
40 / 80 key setting
incorrect
Cartridge not properly
inserted
14
Remedy
Make sure power switch is
in ON position
Check power socket for loose
or disconnected power cable.
Unplug from mains supply
first
i
Check connection with mains
power supply
Replace fuse. Unplug first
i
Check monitor connections
Check 40/80 column switch
on computer and / or monitor
Check computer connection
to
TV
Check output cable
connection
to TV
Re-tune
TV
Turn off computer. Set 40 / 80
key
to UP position for TV
Turn power OFF and reinsert
cartridge