Cordovox piano G keys dead

[roughshawd]

I don't know what this is. Looks like a hairline fuse someone put in it.

Just a scratch. ..,.

 

[roughshawd]

I don't know what this is. Looks like a hairline fuse someone put in it.

Just a scratch. ..

I don't know what this is. Looks like a hairline fuse someone put in it.

This is the tone bar board. There was a shielded, green wire, that may have bent over shorting across these components

 

[roughshawd]

Just a scratch. ..

This is the tone bar board. There was a shielded, green wire, that may have bent over shorting across these components

 

[roughshawd]

No worky.... Whaddya do..mumble mumble...

 

[roughshawd]

Black wire pinouts at the chips read pin to pin 3.3k, except one. Pin 11 reads 44.2

 

[roughshawd]

A hair out of the horsetail is disconnected from the do Re Mi panel...

Would really like to take a vacation when this is working again....

ps. Everything else is checking out ok!

 

[roughshawd]

I fixed the scratch... Made a better ground, and found a loose wire in the key switch pins. I have infinite on the -9v +9v And +12 v ok. I am out of expertise.. I am not college educated.... What would cause my -9v rail to go infinite?

 

[roughshawd]

I don't know what this is. Looks like a hairline fuse someone put in it.

I put the screw in, closed the lid, nothing works...
There is 4.5v on the +9 IC rail....

The "rail" being the shared ic power line

 

[roughshawd]

I don't know what this is. Looks like a hairline fuse someone put in it.

I found the board had a large scratch in it that broke through the trace across one of three traced affected. I repaired the broken traces with a solder jump.

 

[roughshawd]

I fixed the scratch... Made a better ground, and found a loose wire in the key switch pins. I have infinite on the -9v +9v And +12 v ok. I am out of expertise.. I am not college educated.... What would cause my -9v rail to go infinite?

This system uses a -25v rail instead of a -9 or -12v. Testing with my 20v setting on the vom would read infinite.

 

[roughshawd]

Now here is the intonation board...
Why do the trims all read 3ohm when they have 2k2 written on them?

 

[roughshawd]

Power on tests. At the mother board I have +9. , +12v and -21v

 

[roughshawd]

Voltage across the caps, seems nominal...
With resistance tests, no power, I have 3 electrolytic caps which test outside of 200k #27, #37, and #51. The last one, #50 if I include the axial reference.

 

[roughshawd]

Time to get serious.....
Under the tone control is my worst failure... The power board.

 

[roughshawd]

The power board

 

[roughshawd]

It's lonely on top...

 

[roughshawd]

The board was scraped through one of the traces... I did a repair, but I don't know if it will work... to scared to test it...
there was a wire to the main process board which was disconnected, I don't know, maybe the repairman did a check for something and didn't find anything, the in trying to get a signal, realized it was a bad wire.... I am a horrible pessimist! should I test it... yes|no...no|yes...
I should test it.... no no... yes yes... nono. yesyes...
toss a coin? spin the wheel? test or not to test... that is the question....
Ok. enough... the suspense is killing me!

 

[Delta Prime]

test or not to test... that is the question....
Ok. enough... the suspense is killing me!

Test & take a photo of the part of the board that smokes…