Not trying to hijack this thread but it should probably be located in the "Amp" discussion.
Yes, the transducer wire Mike, I mean "Ace" is talking about is located inside the Reverb tank. I would be either on the input or output. If you have a DMM you can measure the dc resistance on each of the rca jacks, if you get no reading from either one or both then one of the wires is probably broke off or worse the transducer coil winding itself may be broken or fried.
Disclaimer: I make and sell Buffers. I also sometimes Modify, Build and sell preamps and amplifiers. My opinions are not intended to be sales pitches. I am a one man shop and prefer to spend time with my wife and family, i work full time on call and love to spend my spare time doing other things. I only make, modify or build things for those that seek them.