Swa1501 nice output till loaded.....

[thelmores]

Have 2 of these amps in for repair, replaced usual suspects R63, R64, R16, R17, R54, R59, R25, R26, R72, R73, Q17, Q14, Q5, Q18, Q15, etc.....

Now, when I input a sign wave at about 70hz or so, I get a clean output with no load, which ends u at about 48vAC......

Problem is, when I hook up a load 16ohm, I can get past about 10vAC and the signal starts distorting.........

Have attempted repairs on both amps, replacing various combinations of the parts above.... and end result, they are both doing the same thing!

Anybody want to take a stab at what I am missing????

These amps are a royal pain in the ass!

Cheers!

[Mick Bailey]

Can you post a schematic, or link to one?

[thelmores]

Can you post a schematic, or link to one?

Why yes I can..... added as zipped attachment. Let me know if you get it ok. Also includes the service bulletin for the diode swap.

Best regards......

[rf7]

Sounds like IC U1 is dead. And it's an obsolete part. You can get them from China via Ebay. Americaii.com has 270 of them, but they have a $50 minimum order.