Anoten twin reverb 65 ri with reverb hum

[wynken]

I got a lot of hum when i turn on the reverb, even with the reverb at minimum or the pan disconected. I swap the pan with a new one with any upgrade.
I replaced v3 and the result was the same noise, then i removed it and there was any improvement.
When i remove v4 the noise disappears, i replace v4 with a new tube an got the problem again.
I meassure the resistors and find all of them are ok,and then i mesure the voltages

Tp7 11mv
Tp9 465v
Tp10 .3 mv
Tp11 .2mv
Tp8 8 v
Tp28 449v
Tp12 2.2
Tp13 287v

There was big differences with the voltages shown in schematics and the mesure ones

What else do i need to check?

[52 Bill]

What else do i need to check?

Welcome to the place.

Are you using the footswitch? If you are, try unplugging it from the amp, any better?

[wynken]

With the footswitch unplugged there is always noise, but when inplugged it the noise could be turn off with the reverb buttom

[wynken]

Also the noises stops when i unplugged the reverb driver

[wynken]

Any ideas??? Please help

[Jazz P Bass]

Ideas.
Well, first off, you need to understand Fenders nomenclature as far as the test points go.

The TPs in a Rectangle are measured in Volts DC.
The TPs in Ovals are measured in Volts AC and are the signal running through the amp, as defined by the setup procedures.
In this case, that would be a 37Mv/ 1KHz input, in the Vibrato Channel jack.

65_twin_reverb_RI.pdf

[nickb]

Any ideas??? Please help

Remove the red (output) reverb tank lead completely -does the hum stop? If it does replace it is likely that the shield is open at one end or the other. Fix or replace with a known good one.

[wynken]

I change all the caps and the noise is gone, except when i plug the footswitch, i check the plug and the switches and all seems well wired, y dont check sny in the amp

[Jazz P Bass]

The Reverb wire used in the Fender Footswitch must be of a shielded type.

What pedal are you using?

[wynken]

The original, it says made in mexico

[wynken]

The noise appears when i put it on the floor, but if i place it over the amp or even my hands it stops

[Jazz P Bass]

That sounds like a grounding issue.

If the pedal is wired properly, it should not radiate noise. (well, not much anyway)

Attached is the amp & pedal wiring.

65_twin_reverb_RI ft sw wiring.pdf

If everything checks on the pedal & jack wiring, then you will have to look real close at the overall amp ground wiring.

Grounding issues can drive you nuts.

there is a wealth of information on this site & the web about proper grounding.
You may have to explore some of that.

[nickb]

The noise appears when i put it on the floor, but if i place it over the amp or even my hands it stops

Check that the cable shield is making good electrical contact with the metal body of the foot switch.

[Enzo]

heck, make sure the shield is around the wire to the reverb switch and not the other switch.