trouble shooting fading channel

[DuaneWhitney]

Hello,

I would appreciate advice on how to trouble shoot a fading channel on my mainline.  It has been working fine for the last year and a half.  Recently, one channel fades out within a few minutes or doesn't work at all when I fire up the amp.  The voltage checks for Breg (220V and 280V) and kreg (2.5V and 1.0V) don't match up with the specs in the manual.  Also, two of the LEDS don't light up.  The other voltage and resistance checks match up with the manual.

Any suggestions on how to track down the problem?

Thanks!

[Paul Birkeland]

It can be hard to see, but I would start by checking to see that all three tubes are still glowing.  Also try swapping the 6C45s to ensure that the issue doesn't follow a particular tube.

It's likely that this issue is just a solder joint that wasn't all the way solid, so it may take some poking around to figure out where it is.