DC-5 blowing fuses

Hey gang,

I just got a hold of a DC-5 head (A-type) that had no fuse and blown power tubes. I replaced both and simply plugged it in.

Kapow -- blown fuse! I didn't even turn it on. When I took a look inside, the varistor had blown.

Any ideas about what's going on with it? I have a suspicion that the person who had it might have turned it on without a speaker load, which may have caused some damage.

Any advice greatly appreciated! :?

Likely the screen grid resistors need to be replaced.

bendo said:

Likely the screen grid resistors need to be replaced.

Click to expand...

Hmm . . . thanks so much, bendo. I also noticed that a wirewound resistor may have blown as well.

I should also mention that the power tubes weren't exactly blown. Someone had tried to pull out the power cord too quickly and broke off one of the power tubes where the glass meets the plastic base, so it was loose, although the base was still in the socket. I wouldn't be surprised if he still tried to plug it in like this.

I'm going to replace the varistor, the 5 watt wirewound resistor, both power and standby switches, and possibly the fuse holder. I sure hope the PT isn't gone. I'm still a bit of an amateur, but I'll take the multimeter to the screen grid resistors too. Wish me luck!