Vintage Synth Repair

Scott wrote:
> Checking power supply rails is the 1st thing I'd do too but with that ,if you can , check for power supply ripple.
> Older units are much more likely to have weak power supply filter caps.You'd need a scope or and RMS voltmeter to check for the ripple.
>
> If someone reworked some rectifiers try and find out WHY they quit.
> Resolder all the comps around the power supply section.
> W/o knowing more about the circuit , that's where I'd go.
>
>   
Thanks for the reply.  I've actually pulled the processor board on my 
OB-8 in order to inspect for damage in the area of the bridge rectifier 
that had been replaced, and I'm glad that I did.  I'm amazed that I was 
able to get seemingly normal voltage readings at connectors I and J.  
I've uploaded a few photos for amusement and review.  They can be seen here:

http://groups.yahoo.com/group/vintagesynthrepair/photos/album/1950312521/pic/list?mode=tn&order=ordinal&start=1&dir=asc

There is also quite a bit of what appears to be "rework" that has been 
done to the board . . . Note the black wires running here and there in 
the photos.  Can anybody confirm that this work is not normal, and was 
probably someone's attempt at a repair?  Any further input on this would 
be appreciated.

Thanks,

george