Trouble shooting ideas for a Bogner Shiva

[maddtapper]

I'm having an issue with my 6l6 Bogner Shiva that you guys know WAY more about than myself! I'm sure it's something minor, but I'm not really sure where to start... So I'll give you the rundown...

I had it on a gig and it started making a Loud staticky noise... Didn't matter if anything was plugged in or not... Initially thought it was a cable so I unplugged everything and it kept making the sound... So I turned it off and assumed it was time to change power tubes...

Fast forward a few weeks... I got some new tubes and went to bias it up and with the bias pot wide open it was only at -17mA. (550ish plate volts)I called Bogner and they told me to change the resistor value...no biggie... I did and it biased up into range... Thought all was good...

Well, it started doing the same crackling staticky thing again... I tapped all the preamp tubes and cleaned the sockets along with the input and efx loop jacks... Seemed like the first preamp tube was too noisy, so swapped it... None would make it recreate the sound by moving or tapping on them...

Now it just faded out... Not sure where to go... And I have NO techs for a couple hundred miles...

Any suggestions would be GREATLY appreciated!

Thanks!

[BLT]

Did you "chopstick," or tap all solder connections from the input jacks on down?

[xtian]

If you can experiment while the static is happening, if you can quickly divide the Potential problems in half to narrow your search. If you plug a cable into the FX RETURN, you will silence the preamp and hear only the PI and power tubes. And if you take a signal out of the FX SEND and listen to this signal on another amp, you're listening to the preamp tubes only.

Just a quick example of one way to narrow the problem search.

[maddtapper]

Think I got it! Thanks for the help! I found another preamp tube that was bad... And the power tube sockets where loose... Tightened them up ,cleaned everything again, and tapped the hell outta everything! So far so good!

Thanks again! I know this is obvious to most, so I REALLY appreciate the input!

[Stevem]

It's been a while since I worked on one of those, but if it does not have retention clips on the output tubes then that would be a good thing to add to combat those output tube sockets from getting loose again!

[Structo]

Yeah, first suspect always tubes unless something else is obvious.

The staticky noise in preamp tubes is something I have also experienced.

Other suspects for that noise is a bad plate resistor, especially CC resistors.