BOP Annoying Switch Problem - Solved

[mark adams]

None of the switches in the head work, i have traced it back for continuity on the green/blue wire, the one common to all the head switches to the associated pin on the socket J206.6
U20 has already been replaced and socketed.
Am i missing something??

 

[chris b]

do any of the other switches work on thar row or column

 

[mark adams]

No, all switches on that column don't work, it all points towards U20, i changed it twice so it can't be that...

 

[mark adams]

Breakthrough, most outputs of U20 show a dead short to the corresponding pin on J206 EXCEPT this one, shows a high resistance, i have a suspected high resistance track from pin 13 U20 to pin 6 J206... Going to try that tonight and report back

 

[mark adams]

My fault finding skills haven't deserted me yet it seems, it was indeed an open circuit track from pin 13 of U30 to the resistor ladder prior to joining J206.6
I soldered in a jumper wire and it all works a treat now

 

[cooldan]

well done sir. finding and fixing a fault can be as satisfying as a good score.

 

[chris b]

nice one mark you up and playing now then

 

[mark adams]

Oh yes.. just some cosmetic work to complete now

 

[stoptap]

Oh yes.. just some cosmetic work to complete now

Don't mix blue eye shadow and red lipstick.

 

[mark adams]

Don't mix blue eye shadow and red lipstick.

David Bowie managed it in Life on Mars....