5E3 Malfunction: Volume Fluctuation

[ululufut]

I built a 5E3 that, when played through the normal channel, produces wide fluctuations in volume. The variation is smooth - no cracking or interruptions - but goes back and forth from very quiet to very loud.

Note: There previously was a "bad distortion" & cutting out problem that was fixed by cleaning out the pots and tube sockets. Could this previous problem have contributed to what is happening now? The amp played perfectly for 45 minutes after the cleaning, and then this volume issue came into play.

The amp is a relatively new build - only a few months old.

[shooter]

Could this previous problem

possibly, how hard is it to just swap out the pot?  try clipping you meter from the wiper to one end and slowly rotate, does it inc/dec smoothly?

[ululufut]

There's the added glitch in that I sold the build to a friend of mine 2,000 miles away. He shipped it back to me for the bad distortion/cutting out issue, however when I got it, it worked perfectly. I had installed a negative feedback on/off switch with the original build, plus a master volume underneath the chassis. I tested the amp in both channels, at all settings, the amp was 100% normal - not cutting out/no bad distortion.

I sent it back, and the same issues reappeared! After lots of troubleshooting, I suggested that he clean the pots & sockets with contact cleaner. The amp started working perfectly, then after 40 minutes of playing, the new issue of volume fluctuation started.

The funny thing is, it was the Bright channel that was having the distortion issues, but now it's the Normal channel that is having the volume issue! The volume fluctuations are wide, however they are smooth - not cutting from low-to-high, high-to-low. I'll have him try metering the wiper and see what happens. Thanks!

[shooter]

when I got it, it worked perfectly.

+

2,000 miles away

-

He shipped it back to me

=? 

[ululufut]

when I got it, it worked perfectly.

+

2,000 miles away

-

He shipped it back to me

=? 

tell me about it

[shooter]

UPS here isn't known for repairs, but finding loose, bad connections in ANYTHING, they rock