Princeton reverb reissue started ticking

[Joe6v6]

I have a princeton reverb reissue that started ticking with the tremelo on. The speed increases with the speed knob, the intensity knob does not affect it. If I shut the reverb off it goes away & the reverb knob acts like a volume control for the tick, with the reverb knob at zero it goes away. With the reverb off the tremelo work fine with no noise.  .   Any ideas? Ive tried swapping preamp tubes with no affect.  .   Joe

[jordan86]

How old is the amp?

[Joe6v6]

 Its 4 years or so old,  never had any issues. Only gets played at home so it hasnt been thrown around or anything.

[Latole]

Princeton 65 reissue ?

Microphonic tube ?

Schematic ; https://www.thetubestore.com/lib/thetubestore/schematics/Fender/Fender-65-Princeton-Reverb-Schematic.pdf

[sluckey]

Unplug the footswitch. Still tick?

[Joe6v6]

Princeton 65 reissue ?

Yes & that schematic looks to be correct

Microphonic tube ?

No , Ive already swapped several different tubes in & out.

[Joe6v6]

Unplug the footswitch. Still tick?

Unpluging the foot switch stops the tick but it also shuts off the tremelo, the reverb stays on.

[sluckey]

Unpluging the foot switch stops the tick but it also shuts off the tremelo, the reverb stays on.

Really? The schematic shows that the tremolo will still be enabled with the footswitch unplugged.

[jordan86]

Could it be lead dress or connections around the reverb and trem jacks? The circuits aren’t really connected on a schematic level. But in the layout they interact at the footswitch jacks. I’d check grounds, jacks, and lead dress around the footswitch connections.

[Joe6v6]

Really? The schematic shows that the tremolo will still be enabled with the footswitch unplugged.

Correction - I didnt pay close enough attention - When the footswitch is unplugged the tremelo and the reverb operate
                                                                       correctly with no ticking.   .   

[sluckey]

When the footswitch is unplugged the tremelo and the reverb operate correctly with no ticking.   .   

The typical Fender two button FS has three conductors in the cable. The reverb uses a shielded wire and the tremolo just has a single unshielded wire. The tremolo switch uses the reverb shield for a ground. Inspect the cable at the plug end and at the FS end for a bad shield connection. Even better, replace the cable with a cable that contains two separate shielded wires.

[Joe6v6]

The typical Fender two button FS has three conductors in the cable. The reverb uses a shielded wire and the tremolo just has a single unshielded wire. The tremolo switch uses the reverb shield for a ground. Inspect the cable at the plug end and at the FS end for a bad shield connection. Even better, replace the cable with a cable that contains two separate shielded wires.

Will Do - Thanks & I will report my findings.   .