[Swarkybubble]

Any suggestions on where or the best way to proceed to start searching for the culprit ?

No, it?s not for me, mine?s still being built "a la tubesforever", it?s for a mate in the UK who knows even less than me about these things.

Thanks for any suggestions.

P.S. - It?s a basic, battery-powered kit version, by the way.

[hagtech]

Did the channel work ok and then go bad?  Or always bad?  Start with power supply rails, make sure they match left/right.  Then check resistor values.  Often it is just the wrong value in wrong spot.

jh

[Swarkybubble]

Hi Jim,
No it was fine and my mate left it on overnight, inadvertently. When he came to try and use it again, the right channel had gone AWOL.

[Swarkybubble]

Hi Jim,
After fitting new batteries and taking out his multitester my techie says he gets  a voltage difference of something like 1.13v at the first gain stage and 1.24v at the second in favour of the left hand channel. After checking the resistors are Ok, the conclusion my techie has reached is that the jfets must be faulty on the right hand channel. Apparently they are going to be a real pain to try and change so would you recommend a new board in such a case or can they be repaired ?

[hagtech]

Hmmm, I doubt it is the JFETS, unless the input tooka big ESD (lightning type) strike, which is possible.  That could do it.  Winter down under?

If you're really good at soldering, the parts are not that hard to replace.  Let me know offline.

jh

[Swarkybubble]

Thanks Jim,
I?ll get my technical mate and solderer to contact you direct and explain exactly what he has found.
Chris