EMU 0404 PCI - Needs a fixin' first, but...

[jbeckva]

I just received an EMU 0404 that was sent for me to fix. Complaint is one of the channels is out.

While offlining it, I noticed that the output dc resistance for the "good" channel is around 50 ohms, but way down there at 4 ohms for the "bad" channel.

I'm thinking it's Q1 which shows the same resistance readings (bad) that Q3 does (good), so Q1 is definitely suspect. But for the life of me I can't find a valid part number for it. It has 6KI (or 8KI?) written on it, but that's all I have.

Would anyone out there happen to have a good part number? Also - is it possible that Q1 and Q3 could be those "muting" transistors? If so, then I could probably just remove it, or ?

Thanks guys.

 

[jbeckva]

Well, I managed to at least figure out that they were the muting transistors on the outputs. I have both removed - even the 50 ohms on the supposedly "good" channel is suspect to me + it would have given a channel imbalance if left in, so both are out of the circuit.

The output sounds great and in both channels now, but I'd sure like to know what a suitable P/N would be to replace them. I guess they could remain out of the circuit. Half on one, half the other - if replaced they could go bad again.. but if left out, no transient muting. I'll tell the owner to always make sure he has the 0404 deselected on his amp any time he's powering the pc up or down.