2203 build losing power...

[JDW3]

I finished my 2203 build and had a hard time getting it to stay "powered". I thought it was the output jacks because when I replaced them, the amp stayed running.

The amp is back to cutting out and now is back on the bench. I have a new standby switch ready to install. I'm not sure if this is the problem.

When the amp cuts out, you can still hear it but VERY faintly. I have to crank the master high to hear it. It's the full tone of the amp, overdriven and everything.

If the standby was not working, would you hear anything at all?

I'm wondering what other possible problems this could be.

[JDW3]

I was about to install the new switch. I figured I'd better measure voltage on both sides of the switch, first.

I hit the power switch and the 4 amp mains fuse blew. This is starting to worry me. The amp was running yesterday and it was cranking; super loud. And then, it cut out. I figured no problem, I have the new switch ready to install.

The tubes arent bunt or anything.

Would a bad standby switch cause the mains fuse to blow?

I'm going to install the new switch and try again.

[vanhalen5150]

Does it only cut out for a short time? I have a 12000 series thats doing the same thing. It goes out for about 3-4 seconds and then comes back on.

[Jingletone]

Sounds like a short somewhere in the B+ chain.Or a cold solder joint, could be any where. Have you looked at voltages on your tube plates while playing the amp and having it cut out? Look at all your tube sockets while playing and see if there is any arcing or sparks. hook a cd or mp3 player up to the phase inverter and see if it plays fine through the power amp. If it does aligator clip off of the center tap on your master volume and play into another amp. That way you can narrow down weather the problem is in the pre or power section. Check all voltages and report back...

[JDW3]

It turned out to be a bad standby switch.

Thanks guys!