Princeton Reverb 65RI Footswitch Changes Vibrato Rate

[scarrpa]

When I plug my footswitch into my Fender Princeton Reverb 65 Reissue, the vibrato rate is faster set at 0 than when it is unplugged. It was fine before I put a new plug on the footswtich. I put a new plug on because it was turning the reverb off due to a bad solder job on the plug. The work I did looks like an improvementm and the footswitch functions well besides this anomaly.

When the pedal is not plugged in I have it set to Rate 0 Intensity 10. It sounds great and I use this a lot.
When I plug the pedal in without changing anything, it sounds like it is set to Rate 4 Intensity 10. I miss the other setting and I have no control.

I'm going to try one of the other pedals I have laying around. I have 3. I generally hate this device even though it looks cool. It slides around, the wire it stiff and poor quality, and the switches are cheap. I keep looking at an aftermarket but never pulled the trigger.

Has anyone heard of anything like this? I saw mods to alter the vibrato on the amp but it had nothing to do with the foot swtich.

 

[schmee]

Strange indeed. Are the RI switches momentary contact or like the old ones?

 

[corliss1]

The RI switches are latching, they just use a TRS instead of the two RCA plugs.

Since the issue happened after you changed the plug, it had to be something related to that work.

 

[Pete Farrington]

By far the most likely cause is bad materials or workmanship.
Clearly it can’t be a hard tip to sleeve short, but did any conductive antistatic insulation around the core get stripped back? It’s usually a thin black layer between the core insulation and the shield.
I was amazed when a friend whose been making his own cables for decades was tripped up by this recently.

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

 

[Lowerleftcoast]

Measure for resistance from tip to sleeve and from tip to ring on the plug. It should read *OL* (open loop) on the meter.

 

[scarrpa]

Right on. I can't wait to get home then! I'll let you know what I find out.

 

[scarrpa]

I had an extra pedal I had to solder the vibe wire on the plug to fix it. The problem is fixed for now. Maybe I’ll try again with a different plug on the other pedal sometime.

 

[scarrpa]

The night after I posted this, It happened consistantly again with the pedal that is working. I'm just going to take it into the shop. It's been like 3 years anyway.