Crumar Musical Instruments User Group.

> LM13700N that needed resoldering. Voice 3 and 4 back were okay now.
In a less 
> professional way (touching everything possible point) I was able to
find another point to 
> be resoldered and now It's fully functional. INo more hisses and
crackles. Not even one 
> component replaced!

Ah yes, that is the 100,000 mile service.  It is the 200,000 mile
service you have to look out for ;)

My Bits were worked on several years ago when resoldering of most of
the boards was necessary.  We went over almost everything since a lot
of the solder joints were bad, and put in sockets for the filters. 
After that, they worked fine for a while, but I think the time (about
24 years, right?) and perhaps a bad voltage regulator took their toll
on some of the parts.  Fortunely, most of the parts in there are
common and cheap, only .50 or $1.  I probably spent a total of about
$60 repairing both Bits, and I have enough spare parts for another 10
years.  Since I didn't know what was bad, I just bought replacements
for almost everything, socketed all of the ICs on the lower board(s)
then started switching them out.  The only expensive parts were the
filters - about $10 each, and fortunately I had a few leftover from
the 100,000 mile service.  I grabbed a few more from the Internet, and
hopefully now that the super high temperature op-amps are out, the
filters would be exposed to such extremes again.

Cheers!