Fender CVR - Vibrato Problem

[fezzy]

Trying to figure out a problem with my fender custom vibrolux reverb amp. When I turn up the Intensity on the vibrato I just get this loud chirping static sound in place of what should be the vibrato swells. Also, when i turn the amp up past 3-4 I get this same sound when hitting a loud note. If anyone can help I'd greatly appreciate it.

I thought it my be a cap I replaced recently but I checked it and its still good. Also checked the 12at7 tube the reverb uses.

Any suggestions on what I should check next?

Thanks!

[ziess]

Does it happen on both channels?

Tommy.

[Kap'n]

Do the plates go red at all?

Have you tried swapping the tremolo tube?

[fezzy]

Does it happen on both channels?

Tommy.

Yes, it happens on both channels.

[fezzy]

Do the plates go red at all?

Have you tried swapping the tremolo tube?

What exactly do you mean by "Do the plates go red"?

I have not tried swapping the tremolo tube. Would that be V4?

Thanks!!

[NTBluesGuitar]

That would be V5.

Plates going red is a tube running TOO hot. The flat grey parts you see inside the tubes would be literally glowing red-hot.

[fezzy]

Thanks NTBluesGuitar. I'll replace V5 and check for any glowing plates tonight. Will post an update ASAP.

[fezzy]

Yep, looks like one of the power tubes, V7, has a very hot orange-red plate.

Also, I noticed that about 20 seconds after I switch the amp on from stand-by a low hum starts and the noise I mentioned earlier from the tremelo will start as well.

[fezzy]

I switched out V7 & V8 with some other tubes. Problem seems to be solved for the time being.