Ampeg SVT 350H problem

[ghostjs]

Hey I recently got an Ampeg SVT 350H (it's old and Made in the US) and it's having some serious problems where it would buzz and significantly drop volume. I tried different speaker cable and plugged through a PA and can confirm it is the head that is the problem. Turning on the limiter wont help nor lowering gain controls. It starts buzzing out notes and lowering the volume sometime around 10-20 minutes of playing. Can anyone help? is this a common or easy fix? I spent good Christmas money on this baby and I cant afford a replacement right now

so can someone help?

(note: i did clean the entire head's insides and everything looked pretty normal)

[BillyB_from_LZ]

Try jumpering the effects loop (short instrument cable from effects send to effects return). Also, if it has them (I don't recall) do the same thing with the preamp output/power amp input jacks. The cheapo switching jacks that amp makers use sometimes get corroded/dirty and cause intermittant problems like that.

[ghostjs]

strange enough, i loosened a screw from the amp head and it started working normally. thanks for the info though! (i might replace a few parts anyway)