the Fly Clone Project

I’m hoping someone here can help me out. The wiring tape for my Fly Deluxe broke, so I decided I was just going to wire it up with a simple 2 magnetic humbucker-only circuit. I’m sorry I don’t have a schematic of what I did, but I just simply kept the stock pickups and pickup selector switch and went straight out from the switch to the 500 k pot that was used for the magnetic pickups originally and then out to the output jack.

The problem I’m having is when I turn the pot all the way down, I get a loud hum. From what I can tell, I have everything grounded properly, and I took the ground wire that goes to the bridge and bonded it to the rest of the grounds. I looked through the schematics here and I think I have it right, but I still have noise. Does anyone have a suggestion that I can try to see if I can fix this?

Thanks.

Is it the hum one gets from a grounding short or cold solder joint? Does the hum go away when you touch the strings? I swear, there must be some undiscovered law of the universe that dictates you have to observe every other component and solder joint before the last one reveals itself as the culprit.

If I’m understanding correctly, you removed everything but the original selector switch, volume pot, and output jack? No hum with the volume pot at anything but 0? Due to the odd pin arrangement of the 90s selector switch and jack, it’s possible that there’s either a short between two pins or that the signal path being taken through them isn’t isolating the start and finish wire signals of the pickups properly.

With any other guitar, I’d say you have a ground wire connection shorting at either the pot or the jack. Any cheap pot, 3 way switch, and barrel jack will fit in your Fly - Worst case scenario, replacing one or all three components will reveal the failure point. In the meantime, a DSS checking for grounding continuity’s all you can do. It sounds like you have a very simple circuit with only a few potential failure points; so hopefully it’s one of those basic gremlins where reflowing the solder at the volume pot grounding points solves it.

Thanks a lot for the reply mmmguitar. I typed that post out kinda fast on my phone and I forgot to mention a couple of key points. I actually swapped out the pickup selector switch with a new one with no luck, and at one point I just took the pickup wires and hooked them directly to a brand new output jack with a couple of alligator clips (in effect bypassing any other volume or tone knobs that might be potentially causing the noise) and I still had a problem.

I even went crazy and just took an alligator clip and connected one end to ground and started touching the backs of the pots and anything else that was made of metal. I don't believe the amp or cable is part of the problem because I tried the guitar on a different amp/cable combination and got the same results.

Assuming you’ve reduced the guitar circuit to

a. a single humbucker’s finish and start/baseplate ground wires,
b. connected to the correct contacts on a common barrel jack, with a
c. grounding wire connected from the same ground contact on the jack to the guitar’s bridge,

then ground hum specific to that guitar would suggest a broken or shorted ground wire in the pickup itself. If you’re getting it from both pickups after testing them separately, then it’s more likely due to the guitar failing to be grounded at the bridge or jack. A broken connection inside a barrel jack sleeve necessitating its replacement is sadly a common failure point to consider.

It seems you’ve already broken the problem down to individual components; so all I can really say is that you’re closer to the end of the fight than the start.

I recently had a gremlin in the form of a barely visible solder bridge shorting contacts in a selector switch, combined with a neck humbucker in which one coil was shorting between bobbin and baseplate. I alternated between being convinced it was either the switch or the pickup before being gobsmacked at the realization that each component had a short reproducing the same issue (a single switch position with no sound). Conspiracy, I tell you!