In a bind, bias mod question

Hello Boogie land!
Ok, I have a big gig tonight. I screwed up and need help!
I have a heartbreaker combo I bought years ago from Monsta Tone
Andy Turner here on the forum. The reverb has quit working and
I was trying to figure out what was wrong. I saw a pot with a short, short
shaft beside the in/out of the reverb. I didn't know what it was or even if it was stock and I moved it.

Now I am thinking Andy put it there as a bias knob. So...****! I know squat about
biasing, having been a boogie guy forever.

No way I can take it all apart and learn to bias and make load in! Am I in danger of causing my amp
to fail in front of probably the biggest crowd I ever have or will play for?

Any help/advice/insight/educated guesses welcome and appreciated!

Stephen

Have you tried to contact Andy with a PM?

Pictures would help.

If that is indeed a bias pot, when you randomly turned it you have done 1 of 3 things:

1) you've adjusted the idle plate current too high and will cause one or more tubes to "red plate" possibly damaging the amp.

2) you've adjusted the idle plate current too low resulting in an amp that is anemic sounding, thin & under-powered. You prob will not damage anything more than your rep.

3) you've gotten lucky and stopped somewhere in the safe operating range of the tubes.

Do you know anyone with a bias probe?

Dom

The rest of the story....
So it wasn't occuring to me the huge time difference between me and Andy.
He called me back at what was still very early in the morning for him.
Again, great guy.
No, no bias meter available.
But I explained to Andy I had made the mistake Thursday night, played the amp
five hours on Friday night, and then later realized what I had done.
He had me play it for 20 minutes while watching the tubes.
It was fine, still sounded great, and we had a good show!

Oh, and he had me order a bias meter!

Thanks!

Glad it all worked out well.

Andy's a great guy for sure.

Rock on & enjoy that amp!

Dom