so just to clarify, you're still having issues after the tubes were replaced.

did an amp tech replace the tubes?  and did the tech check and adjust the bias:

Q: What is the bias voltage for the 6L6 tubes?

A: 35 ma (or mv)

taken from: http://line6.com/support/docs/DOC-4540

Also please make sure you only use 6L6 or 5881 tubes.  5881WXT tubes are the stock, and it's the same as a 5881 but with a larger plastic base.  note that 6L6 tubes are not the same as 6L6GC tubes, and in previous conversation with the technical guys at Line 6, 6L6GC tubes should not be used as they have different electrical specifications, and as Bogner amps are 'hot rodded' by default, it's best not to use different tubes, as they can cause damage to your amp.

Sometimes when tubes pop they can take out resistors and other internal components too, although that usually happens with power tubes pop.

realistically, it's perhaps best to take the amp back to be serviced as it certainly sounds like something is up, and with tube amps there's very little you can do to resolve internal issues.  You can try to re-seat the tubes, but first power off the amp leaving the standby switch set to on, and leave it unplugged for a while, turn standby off and then remove and re-insert the tubes.  also reset the amp (this will wipe all your custom settings) hold the channel A button while turning on the mains power switch, and follow the screen instructions.  If it's still not ok, then get it serviced using an authorised Line 6 service center, as they can check out everything in the amp to make sure it's all working ok. http://line6.com/service_centers/

Please let us know how you get on.

Cheers

Rowbi

I used a cheesy computer power cable instead of the one it came with and it did wonkey things.