Sudden Drop in Output Level (54 Rhodes)

[karst]

Hoping someone here who has more experience can give me some help.

I rebuilt a 54 Rhodes a few years back and it's been sounding great until just a few days ago, when the signal strength going out of it into my amp suddenly dropped to barely audible.

I've eliminated the possibility that it was the cable or the amp by trying multiples.There's still a signal, so I do not think it's a problem with the pickups (all remain magnetized). I'm assuming there's some issue going into or out of the RCA jack or possibly with passive electronics (which I replaced with Vintage Vibe's assemblage during the rebuild).

I haven't seen any obvious issues like loose connections, but if anyone has a rundown of the things to look at, I'd deeply appreciate it.

Attaching a photo of the Rhodes, just for fun...

You cannot view this attachment.

[sean]

How about some photos of the pickups?

If it is wired with that horrific criss-cross patern, then look for touching wires.

If it is wired normally, in groups-of-threes, then use your multimeter to search for a bad group, or bad pickup.
See https://ep-forum.com/smf/index.php?topic=9989.msg55589#msg55589

Using clip-leads to short out large sections of the pickup rail can narrow down your search for the problem.  (If you short across a section of pickups, and your audio comes back, then you know that the problem is in the section that you bypassed.)

I don't suspect the name rail controls, but it is pretty easy to eliminate them from the circuit by plugging your amp in to the RCA connector on the pickup rail. 
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Now, you might want to sit down for this:  are your pickups wrapped with white tape?  White-taped pickups are often maligned, but probably deserve their bad reputation.  Get a bright flashlight, and look closely at the connections of the pickup windings to the solder-lugs on each pickup.  Search for a tiny hint of green corrosion of the copper conductor.

Study this photograph:


Sean

[karst]

Hi Sean, thanks for the advice.

This one is wired all in one big series (like all 54's, I think). No touching wires and no signs of corrosion. These are also clear tape pickups, not the white ones.

My understanding was that when the pickups are wired this way, a single failure anywhere causes failure everywhere and I was assuming failure meant no audio at all, not suddenly very quiet audio.

The good news is that I just tried bypassing the rail RCA cable and my signal came back, so it has to be downstream of that. Will reach out to Vintage Vibe and see if they have any advice for repair.