Different Hot rod deluxe

[nosaj]

Got a hot rod deluxe in lots of crackling and popping. Some filters were leaking. So I replaced the filter caps for HV and LV rails Resoldered the tube socket board all joints. Main PCB resoldered the inputs and controls .

After a few minutes it will started crackling and making noise with nothing plugged into input.
Master Volume will control vol of noise.
Plugging into power amp jack noise is gone power amp clean no crackling or hum.
Pulling V1 and noise is still there.
V2 ground pin2 kills some noise ground pin7 all noise gone.
Tone controls do not seem to affect it at all.
Would noisy plate resistors on V2 be a logical assumption?

Thanks,
nosaj

[Chuck H]

https://schematicheaven.net/fenderam...rod_deluxe.pdf

[Chuck H]

Well you've definitively isolated it. It could be a plate resistor. I'm thinking a spotty relay contact or related for K2B switch. Only because the HRD looks to use carbon film rather than carbon comp resistors and the trouble seems to be isolated to between V2A output and V2B grid. Only one carbon film resistor in a low current voltage gain stage going hinky? So I'm thinking the relay or it's adjacent ribbon or board connectors.

[Jazz P Bass]

It was not stated but is the Clean channel noise free?
I would think yes as the Master volume is only used on the Drive channel.
Does More Drive make the matters worse?

[nosaj]

Noise on both channels. More drive doesn't really affect it.

I've tried flushing the selector switches. But no improvement. I don't have any relays on hand so will have to order some.
nosaj

[The Dude]

Have you tried a new tube in the V2 position? It could just be a tube that gets noisy after it warms up.

[galaxiex]

.................

Plugging into power amp jack noise is gone power amp clean no crackling or hum.
................

Thanks,
nosaj

Maybe it's the jack?

[nosaj]

Which jack? Jumpering pressure and post has no effect on noise. Will try another tube.
nosaj

[galaxiex]

Which jack? Jumpering pressure and post has no effect on noise. Will try another tube.
nosaj

Sorry, the power amp "In" jack.

Isn't it a switching jack that has contacts to "disconnect" the Pre amp?
Aren't they known to get flakey on the switching contacts?

[nosaj]

Sorry, the power amp "In" jack.

Isn't it a switching jack that has contacts to "disconnect" the Pre amp?
Aren't they known to get flakey on the switching contacts?

When I plug a guitar in the power amp in jack it is nice and clean no noise.
nosaj

[galaxiex]

When I plug a guitar in the power amp in jack it is nice and clean no noise.
nosaj

Yes, I get that.

It's when nothing is plugged into that jack, the internal contacts allow the amp pre-amp signal to pass to the power section.
If those internal jack contacts are flakey, dirty or otherwise compromised they can make noise.

Look at J4 on the schem.

See all those contacts? They are known to cause problems.

[nosaj]

These are the ones with the clear plastic over them. contact cleaner not making a difference. Any suggestions on how to determine if in fact it is the jack without replacing it to find out?

thanks,
nosaj

[Enzo]

Yes, plug a cord from send to return to bypass the contacts.

[Chuck H]

After I posted I considered the tube replacement that Dude is suggesting. If this hasn't been done yet, I think it's a good idea. Modern preamp tubes can be "funny" sometimes. Not Ha ha funny. More like "does this fish still smell ok?: funny.

[SoulFetish]

Some old versions use a 1M resistor in the JFET switching circuit that goes noisy and was replaced by a diode in subsequent versions if memory serves. May want to check that