Hey Tom - Thanks for the reply.
David.DiG sent me the CLIP (I'm hosting it here for now?) and that provided the key detail to identify the bits.
The top of the board near the input looks like this:
but it turns out that the attenuator is on the bottom of the board:
This part is AT1, which interestingly doesn't seem to be listed in the parts list but is marked on the schematic and the IC itself as 1GM1-4203. Now either that has failed in such a way to put 15dB of attenuation inline or something in the control circuit has died and is asserting some combination of control lines to drive AT1 to 15dB.
I don't know if it is safe to apply an Occam's Razor to this but it does seem more likely that AT1 died than multiple op amps (MC33178D), resistors or capacitors have died.
It looks like I might be able to remove the shielding and plug the card in and probe the control lines to see what is asserted.
If anyone has any other suggestions I'm open to thoughts/comments. Any idea of where I might get a replacement 1GM1-4203 would be helpful as well.
Thanks,
TonyG
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