Ampeg BA115HP low volume

[pontiacpete]

I'm working on one of these, and i'm stumped at the moment. It is passing signal but the volume seems low. So I start at the power supply
The HV looks goods at about +/-55, but there's a problem with the 16v section. There is only 2.9v and -5.4v on the opposite end of R66 and 68.
The first thing I thought was that the zener diodes(D11 and D12) at this point must not be working, so I changed them and no change in the voltage. I even went as far as replacing C39 and 40, since I'm throwing parts at it in the dark, but no go.
Now I'm here asking for help.
Is this voltage problem in the pre? Maybe one of the ICs?
What would hold the voltages up like this.
BTW R66 and 68 are both measuring 330 ohms.
Thanks for any suggestions!

pete

[The Dude]

"Look" with your fingers and see if one of the op amps is getting hot. You probably have a shorted one.

[pontiacpete]

I have tried a few other things, and that was one of them. Had the amp on for about a minute or more and the ICs did not seem to be getting warm.
But now trying again and I've had it on for a while and U4 might be the hot one. No it definitely is hot. I will change and see what happens
Thanks Dude

[The Dude]

Before you install the new IC, check voltages while the IC is out and see if your +-15 come up.

[pontiacpete]

I beat you to your last post. Dropped a new one in and it's working. 16v supply is back.
Thanks again for your help!!