Conrad Johnson LP66s Problems

Hi All,

I am looking for advice before sending my amp to Conrad Johnson for repair.

I am at least the second owner of the amp and it is all original as far as I know. I have not opened it to look inside.

Recently the amp has been behaving funny:

1. when I go to bias a new set of tubes, a red warning light will flash but not for the tube I am biasing. Used to be only the red light for the specific tube would flash. This can happen on any of the four positions. I keep adjusting each tube and eventually this stops. Is this normal or a sign of a problem? 

2. I start it playing. Occasionally, one channel will go out and then come back on with a thump. A while later, it will do this again. It does this with tubes from three different manufacturers - 6550's and KT88's. I have started trying to rotate tubes and it seems I can move this problem from the right to left channel, but because I only have four tubes from each manufacturer, I cannot figure out which of the two tubes it is. Can 6550 tubes from two manufacturers be intermingled to figure this out?

3. It does not make sense to me that all three sets of tubes would start to exhibit this problem at the same time. All three sets of tubes are used...but I am thinking there is wrong with the amp?....

Advice and suggestions, please. I have tried to contact CJ but get routed through a help desk and then I get a call back a couple of days later from a customer rep and a not a tech. Not making much progress....

Thanks for listening, 

Dsper