3 way NFB switch troubleshooting

[Ledvedder]

I'm hoping some of you more knowledgeable folks can offer some thoughts and pointers for troubleshooting an issue I'm having with my 5e3 build. I've added Rob Robinette's 3 way NFB switch to it, but it's not functioning correctly. In the stock position, it seems fine. But I've never owned or played a tweed deluxe, so I'm assuming it's working as intended. When flicking to the middle position, the sound just slowly "fizzles" out. Then, in the 3rd position, the volume drops pretty dramatically, and the sound sort of "farts" out if I whack the strings hard. I'm using a 3 way impedance selector switch, with a 56K resistor from the NFB switch to the 8 ohm tap pin on the selector.

Here is the impedance selector wiring. 56K resistor from NFB switch to the same pin as the yellow wire.

This is the 3 way NFB mod, https://robrobinette.com/5e3_Modifications.htm#Switched_Negative_Feedback.

[pdf64]

Perhaps you’ve muddled up the wires to the resistor and cathode?
What resistance do you measure between cathode and chassis in each position?

[Ledvedder]

Perhaps you’ve muddled up the wires to the resistor and cathode?
What resistance do you measure between cathode and chassis in each position?

Cathode pin on v2 (pin 3)? Cathode resistor? Or cathode bypass cap?

[pdf64]

The V2 pin3 cathode.

[Ledvedder]

Here is the switch. Top lug with 56K resistor goes to 8 ohm tap. Middle lug yellow wire to v2 pin 3, black wire to 1.5K cathode resistor. Bottom lug goes to 22uF bypass cap.

I'll get MM readings shortly.

[Ledvedder]

I had the resistor and bypass cap wires reversed 🤦‍♂️

[kagliostro]

Dont worry, sometime happens

Franco