PEAVEY MARK IV XP troubles

[Ferret]

Odd thing and not sure what could be doing this. When I get to a gig, set up - bla bla bla, then turn on my Mark IV and nothing. Lights are on so there is power. I crank the volume, nothing, start playing - can hear a faint distorted sound then BOOM, the amp is on and of course scaring the heck out of the crowd!
Once the amp is on, it is perfectly fine for the rest of the night, not a single problem.

BIZARRE, any thoughts out there.

Cables are all fine, cabinet is fine - run two cabinets and two heads (peavey and a Trace) and so I swap things around just to make sure its not something else.

[Dekker]

Two things come to mind.

1) Could be just the normal delay as the capacitors charge (soft start). But if you use the amp regularly, and do not experience that on other cold-starts (when the internal caps have not been charged for a while) then you can discount this possibility.

2) You have a broken solder joint on your input or output jack on your amp. Had this happen to mine. Over time, plugging in/out the jack can wear on the portion of the jack where it is soldered to the IC board beneath it. The slightest movement can then open or close the connection. If this is all it is, it should take you 5 mins with a solder iron to melt and reset the joint. OK, more like an hour with disassembly and dusting if you're doing it yourself...