phonics digital 397 volts on output

[ian33]

I am getting -11v on the -speaker bridge terminal.This is happening when i turn the gain all the way up.could this be a bad opamp in the input section?

[Perry Babin]

It could be a defective op-amp. Do any op-amps have more than ~0.01v DC on their output terminals?

[ian33]

i am geting +8.8v on pin 7 on one of the opamps.It also looks like the gain port is connected to it.In my first post i said there is volts when the gain is up but it is when the gain is down.

[Perry Babin]

Post the voltage on all pins of that op-amp if you haven't replaced it yet.


Pin 1:
Pin 2:
Pin 3:
Pin 4:
Pin 5:
Pin 6:
Pin 7:
Pin 8:

[ian33]

yes i already change the opamp but still same problem.so i also change the gain port and there is no volts now.I never thought a gain port could cause a problem like that.I will mount it back to the sink to test for audio

thanks

[Perry Babin]

If the pot was in the feedback loop for the gain circuit and there was an open connection between the pot and the op-amp (could be internal to the pot), that could cause a DC offset.