Hartke HA7000

[xtian]

Hartke HA7000 bass amp on bench, signal is intermittent and distorted. "Tube" channel works ok, but "Solid State" channel will not pass signal. See schematic snip: I show where the signal vanishes. I see DC voltage (about -13vDC) on the output of that amp stage at pin 7. I do see +15vDC at pin 8 and -15vDC at pin 4. And I do see my signal at pin 6.

Can we conclude that that chip is burnt?

[xtian]

Oh, well. Owner decided not to repair.

[xtian]

Well, the game is afoot. Repair is back on.

[Jazz P Bass]

That is odd. Pin 7 at -13Vdc.

Change out the ic.

[Enzo]

Probably bad IC, but pull the chip first, and check the solder pads with no IC to make sure no funny voltages are coming in from elsewhere, then if that is OK, you can install the new IC.

[J M Fahey]

Yes, bad Dual Op Amp.
Get the original one to keep owner happy but any TL072 (cough cough) will work exactly the same, it's a very light duty job.