Help with Tube Preamp pedal please

[dmk]

i should start by saying thats this isnt really the right place, been that its not something i've built. but i dont know where else to ask, or to begin really.
the pedal in question is a hughes and kettner tube factor.
the problem is that i'll plug in and start playing and after 5 or so minutes, the output will gradually start to fade away to nothing. i've changed the valve twice just to make sure i didnt have 2 duffs.
some people have suggested that it might be the filament power regulator. would this cause a post gain drop in signal? the strange thing is that if i give the pedal a kick (i know), it'll fade back in to life for 30 seconds or so. and then fade back to nothing.
i've only ever build a few fuzz's and messed about with OD's so valves are totally foriegn to me i'm afraid.
any help anyone can give would be fantastic.
preferably a starting point. i like to learn from fixing things

mark

[d95err]

These kinds of problems can be due to a bad solder joint somewhere. When you've played for a while, the tubes and other components heat up and expand a bit. If there is a bad solder joint somewhere, the movement of the expansion can cause it to disconnect, sometimes gradually. The fact that it starts working if you give it a kick makes it more likely that there is a bad connection somewhere.

[puretube]

I`d contact Hughes & Kettner directly!
since this seems to be the more than third time
this phenomenon occurs,
they sure would like to know about this problem themselves.

If everybody tries to repair it himself,
they will never learn about their fault.

At least I`d contact my dealer, and ask him to report H&K about it...

[dmk]

thanks for the reply(s).
thats good news and bad news. hopefully its just a bad solder joint somewhere. the hard bit will be trying to find out where!
wish me luck.
i've had the pedal for about 3 years now, so i'm not sure the shop i got it from will want to know anymore.
about a year back, the internal tranformer blew and i contacted hughes and kettner about trying to get a replacement. all i got back was the usual contact your country's distributor who in turn said contact hughes and kettner. so i think that might be a dead end. thanks for the suggestion though.

mark

[puretube]

no dead end:
I`ll tell your problem to the boss,
he will tell his engineers...

I`ll ask him for a special service/warranty address.

BUT: not before coming april, at Frankfurt MusikMesse.

promised!

[dmk]

thanks very much!
hopefully i'll have it sorted out by then 

[puretube]

maybe it will help hundreds of others, then...

[dmk]

just a quick update.
i've resoldered a few dodgy looking joints.
i also found a cracked joint where i replaced the transformer 
all seems to be working fine now. so hopefully mystery solved.
thanks again to everyone who advised.