Looking for some VVR guidance

[yodermr]

Well I tried to do it completely on my own but I have issues. I built a express with the VVR. Everything looked over well, fired it up and have some strange stuff going on. Won't dive into all the details just yet, cuz I spotted something that might need to be dealt with first and then I shut it down....

I think I installed the larger mosfet on the VVR board backwards (pin 1 where 3 should go?). When I read the instructions and it said that it could be mounted on either side, my inexperience with these and my layout lead me to ultimately flip the outside pins. Figured it out when I took a closer at Dana's pic here...

https://tubeamparchive.com/viewtopic.ph ... c&start=15

So the question is what damage did i do? Can I just flip the mosfet or did I fry it?


My other symptoms (quick pass)
No tube, power levels looked good, with tubes in...
V1a, V1b plate was showing -9.0v...traced it back to the last 9.1K dropping resistor. That seemed to be dead. Replaced it and now I got 90v on V1a, V1b plate. Better but not right.
Sweeping the VVR pot I get some noise between 60-80%, the voltages follow very slowly
I get a bit of breakthrough distorted sound
With no tubes I got -30v on the power tube bias, but with tubes in I measure 0.0v

Anyway first things first. Mosfet screwed?

Thx
M

[UR12]

it shouldn't hurt anything to flip it and retry it. It will either work or it won't.

[yodermr]

Thx, just wasn't sure. I blew the last 9.1K resistor. Flipped it around, replaced the resistor and bingo all is good. Its is alive and well, little biasing and clean up and away I go.

Thx for chiming in