Help needed on Earthquake d2

[amc32]

Power supply is good and I have modulation at output fets. can't seem find my low voltage for opamps or their source for it.

[Perry Babin]

What is the DC voltage on the NJM3403 nearest the RCA jacks? Place the black meter probe on the chassis ground terminal of the amp.


Pin 1:
Pin 2:
Pin 3:
Pin 4:
Pin 5:
Pin 6:
Pin 7:
Pin 8:
Pin 9:
Pin 10:
Pin 11:
Pin 12:
Pin 13:
Pin 14:

[amc32]

Pin 1:5.79
Pin 2:5.80
Pin 3:5.80
Pin 4:10.32
Pin 5:5.72
Pin 6:5.80
Pin 7:5.80
Pin 8:5.80
Pin 9:5.80
Pin 10:5.72
Pin 11:.002
Pin 12:5.75
Pin 13:5.79
Pin 14:5.79
These are the voltages as you requested.

[Perry Babin]

The voltages are just about what I'd expect. There's no missing supply voltage.

Have you tried tracing the signal through the op-amps?

[amc32]

Yes I have and found no signal, no output. And what actually supplys the low voltage supply,I cant seem to see any 7815's or zeners or drop voltage resistors. I guess i will check my pots next. Any common problems associated with this amp you are aware of off the top of your head.

[Perry Babin]

I don't remember having any problems with the preamp section.

For some of these amps, the positive supply is connected to the 12v source. There is no negative supply. The negative supply pin is tied directly to chassis ground. The signal is biased to ~6v.

If you don't have signal on pin 1 of the 3403, you may have broken connections on the RCA jacks.