Acoustic bass head problem

If it makes any volume at all, the transformer is OK. (it's either good or bad, it doesn't go "weak")

More likely reasons:
1) one or more filter capacitor has detiorated, usually accompanied by a hum. Very common problem with old amps as the electrolytic capacitors age.
2) coupling capacitor going/gone. I had this problem myself with my old Ampeg.
3) one of the resistors on the power tubes has burnt out. (fairly common)
4) oxidation on input/output jacks or tube sockets (common, but usually accompanied by loud crackling when plug is wiggled)
5) oxidation on potentiometer (commone, but accompanied by loud crackling when knob is turned)
6) tube burnt out--not as likely as people think)

Psycho Bass Guy is best resource to help you out. With a good schematic, a good meter, and some basic troubleshooting ability, a tech out to be able to isolate problem very quickly.

 

I think he posted a response on a thread last night, or maybe night before. Hopefully he'll see this thread and respond, if not look for him (do a search for psycho) on this forum and PM him. I think he's out of Knoxville TN.

 

Could be a whole slew of things, like nashvillebill said. To add to that, OT's can intermittantly short, but that usually toasts the output tubes. The best thing to do is let someone who knows what they're doing open it up and troubleshoot it. Without a WHOLE LOT more info, I can only give you help in the most vague sense.

 

Is the driver tube OK?

Also, does it have an output jack configuration like a Fender?...the main speaker jack is a shorting type to protect the OT if it is turned on without a speaker connected? If you're using the wrong speaker jack, this would be a likely symptom...

Check to make sure that the jacks are clean too.