• The move to the new server is done. There are some software and database maintenance updates in process. This has us passing the hat around to help out. We appreciate any donations. Seriously, even a dollar helps. The payment page may be found here - https://www.audiokarma.org/support.html

McIntosh MC2105 and C30 power issues

Really, really sounds like a cold solder joint.

Obviously could be anywhere but joints with a high thermal mass to solder are always suspect.

If I remember correctly the factory would solder one the connecting nuts of the TO66 transistor to the board. Almost need to get out my good old Weller soldering gun to get those connections hot enough.
 
There are any number of reasons to perform the driver board upgrade but in this case I truly doubt if they would solve your issue unless the expected bad solder joint is at one of the connections of a replaced part.

I would hope that your tech has reflowed all the boards joints, especially if someone in the past had missed up a repair because of the damn solder tubes used.

A sudden transient spike like you are describing is so often caused by a bad solder joint it has to be the prime suspect.

Oscilation issues would be observable on your tech's scope as they built up to the threshold........

Which is why we always recommend a proper bench test has to be a part of any responsible repair.
 
You must log in or register to reply here.
Back
Top Bottom