Hot Rod Deluxe hums

[Dave Johnson]

Hi all, I have a 2004 HR Deluxe that hums loudly after being switched on. The hum comes thru the speaker, with or without a guitar plugged in. The hum is constant, with volume on zero or full. Amp hums even without pre amp tubes in it. Changed out all tubes to no avail. Tried two known good sets of power tubes. No difference. Amp does work, but the hum is not normal. Any thoughts or ideas?
Thanks, Dave

[Bob-I]

Most likely power supply caps.

[Dave Johnson]

Thanks Bob, I have two caps that look like they might be leaking, there's a funky residue at the + side lead coming out of the 22uf caps. C35 & C36. Seems like a good place to start. I've never seen a leaking cap before, so I'm not sure what I'm seeing, but it's only on the two. Not the others.

[Structo]

Post a picture of them.

[jaysg]

I just fixed a Hot Rod Deville. It had a bad 22uF/500V. Previously, someone had replaced the pair of 47uF/350V caps on the screens...so 3 out of 6 Illinois Capacitors have been replaced. If it was my amp, I would shotgun all of them as a good will gesture to the amp.

[Dave Johnson]

Thanks for the replies, it turned out to be the leaking 22uf 500v capacitors. I was going to change them all, but all I could find locally was two of them. And I had two leaking... So I accepted my good fortune and put them in. It worked. This amp idles as quiet as can be. Hum is gone completely. Rechecked the bias, and buttoned her up. Once again I got lucky. Thanks for the help and encouragement.
Dave

[Structo]

I haven't read very good things about the Illinois caps.
And no, they aren't made in Chicago.

[Bob-I]

Glad it worked out. You might consider ordering some more caps and replacing the rest. Chances they're on the way out too.

[C Moore]

I just fixed a Hot Rod Deville. It had a bad 22uF/500V. Previously, someone had replaced the pair of 47uF/350V caps on the screens...so 3 out of 6 Illinois Capacitors have been replaced. If it was my amp, I would shotgun all of them as a good will gesture to the amp.

Fender had a bad "bunch" of caps from IC. It is hard to imagine the quantities that a company like Fender buys. A certain value cap might last them a long time and go into many amps. I think the Blues Jr/Pro Jr series had a bad run of those caps as well. I do not think it is indicative of the IC quality as a whole. I think it was more a case of a company that makes tens of thousands of components having a "bad run". At least. that has been my understanding of the situation.
I am not apologizing nor endorsing IC caps. I have used quite a few of their filter caps, of all different values, without failure. I know a lot of other users who have had no problems. Probably just something that happens in the course of huge productions. IC sure has had their fair share of bad press, that is for sure.

[jaysg]

I'm not sure what you'd want...Nichicon maybe. Atoms are too long in those locations. I had an oddball that fit and I'd used its bretheren before with no problems.

[hellhound]

I just fixed a Blues Deville reissue which was making an awful cracking noise. One of the IC 22/500 caps had a broken leg. It took a while to figure it out because the caps are glued to the PCB and the crack was not visible. HH