Fender Hot Rod Deluxe Channel switch buzz

[pyjamas27]

I have a USA Fender Hot Rod Deluxe, it has a channel switching issue with both the facia switch and floor switch. When the channel is switched it creates a loud buzz, enough to make you switch straight back. What's causing this?
Any ideas welcome.

Thanks

[Structo]

With both the footswitch and panel switch doing the same thing, it may be
a relay.
Also these amps use quite a few solid state parts that could have failed.

Tubes should always be the first suspect if there isn't something apparent.

If you have known working tubes, substitute each one until you find the culprit.

If it isn't the tubes, you need a qualified tech to troubleshoot it for you.

Good luck!

[martin manning]

I believe I have heard that the two 470R 5W power supply resistors that often overheat in these amps can cause problems like this. They are in with the +/-16V supply for the solid-state stuff.

[Stevem]

Sounds like the relay is bad, or its not kicking over, but swapping just the first two preamp tubes should tell ya something if its tube related or not!

[pyjamas27]

Thanks Guys,
I just replaced all the tubes which cleared up a lot of crackles and pops so I don't think it will be tubes.
Any info on where the relay is situated?

[xtian]

See post #4 here:

http://forums.fender.com/viewtopic.php?t=34196

[pyjamas27]

OK great, Some things to check here. The reverb also doesn't work so it may be linked to the same problem, that was the next thing to tackle. The reverb looks fine and there is a signal from the send cable, so maybe it's all tied up in this.

Thanks

[billyz]

95.% of the time it just those two 470R 5W resistors. they un solder them selves from the board and the relays dont work or float around. the rest of the time its the reverb tank coil or tank wires.