Valvestate 8200 volume fade

[Disincarnated]

Hi guys! Newbie in here. I have a wicked problem with my old Valvestate.

The volume started to fade years back after playing for a few minutes. It also happens on 3 other Valvestate's I owned in the past.
This time I said to myself... I will not give up!

So I did not ... I re solder every single joint on the whole amp. I replaced both mosfets. And then it WORKED!!!! I was really happy for about 6 months and last night I replaced all pots on it cause they where worn out totally.... All I touched was the pre amp board and now BANG the volume drop is back again?!

As it happen after I changed the pots I cannot see any other reason than the issue is located on the preamp board.... Anyone have a clue on how to proceed ? I'm thinking if it could be the PNP transistors on the preamp board?

And to give you some more info:
Tube glows
All jacks are cleaned and nice
Amp works perfect without drops through loop
Volume drop/fade is on both clean and odd channels

Anyone have a clue what could cause this ? It must be a bad component somewhere... If I must I replace every piece of the preamp board but I'm not a skilled electrician so know what to measure and how to do it is my weak side ....

Thanks in advance!

[Sowhat]

Don't go looking for problems that most probably are not there, it will drive you crazy. If you replaced the pots then it's in that replacement where your problem lies. Check and reflow all the pot solder connections again, it's very probable that you have a loose or cold solder there somewhere. Also it could be a bad ground connection on one of the pots or jacks, sometimes we forget to tighten the hardware properly or leave out a star washer when we reinstall things.

[Disincarnated]

Hi and thanks for your replay.
Normally I would do as you say and that's what use to be the reason ... BUT in this case its something else cause I really checked all the pots over 3 times now.
I think some component on the preamp was "again" bent, moved, heated when I replaced the pots and that is the main reason for this issue ...
Cause the pots are fine and values between them fine... So the issue must be something else .. I bet its a component somewhere that I just had luck to get going and when moving the preamp board out of the amp once again made it come back .... ?!
Gonna try some more tonight ...