studiopaul
Member
Currently working on my defender, all works fine except has no sound.
have checked voltages at sound board.
Sound
= +12vdc
= -5vdc
= -13.8 vdc. (too high?)
Pushing and holding button on sound card produces no sound.
this also has a toggle switch..i have tried moving this in both positions with no effect.
AMplifier has hum when turned up loud.. static on pot..assume speaker and amp are good
I have also reflowed all pcb
andbuzzed out ribbon from rom board to sound board = all tested ok
Switched out 6808p ..same problem.
and cleaned rom1 from rom board
Rom board bellow has the 2 far leds on 2 closest off.
Where should i begin my testing?
So far I have read to replace C13 and C14 although the board layout looks a little different
not a technical test ..but placing fingers near sound rom..hearing faint garbled defender sounds???
have checked voltages at sound board.
Sound
= +12vdc
= -5vdc
= -13.8 vdc. (too high?)
Pushing and holding button on sound card produces no sound.
this also has a toggle switch..i have tried moving this in both positions with no effect.
AMplifier has hum when turned up loud.. static on pot..assume speaker and amp are good
I have also reflowed all pcb
andbuzzed out ribbon from rom board to sound board = all tested ok
Switched out 6808p ..same problem.
and cleaned rom1 from rom board
Rom board bellow has the 2 far leds on 2 closest off.
Where should i begin my testing?
So far I have read to replace C13 and C14 although the board layout looks a little different
not a technical test ..but placing fingers near sound rom..hearing faint garbled defender sounds???
Last edited:

