LSS effects loop not working

[Sharp5]

Just got a Lonestar Special head and I'm not getting any sound when I engage the loop and have effects in it. Any ideas? Thanks.

 

[fox5150]

I would try two things, easiest first:

-try putting a patch cable from FX Loop Send to FX Loop Return, i.e. with no pedals. If still no sound then try:
-the effects loop is tube driven. Try changing out V3 with a known working preamp tube.

 

[Sharp5]

Thanks. I tried putting a cable from the FX send to FX return but nothing still. I now get a very faint signal on he gain channel but nothing on the clean channel. Also tried DeOxit on the send and return jacks but no luck. Preamp tube then? I don't have the footswitch. Would engaging the solo function make a difference with the effects loop problem? I'm guessing not but just trying to eliminate any possibilities.

 

[fox5150]

I'm not sure about that as the Solo function is part of the effects loop circuitry, so it could be affected. I'd try swapping the V3 valve over and see what happens. If that doesn't work it's time to take it to an amp tech.