NiteFly Piezo Troubleshooting and EMGs

[vaya]

I recently got my hands on a cheap NiteFly with serial number 092169 that had a non-working piezo pickup. I got the piezo working for a couple of days by just twisting the knobs to knock away any contact rust, but it failed on me again. What would be a good way to troubleshoot?

Also, since everything mounts to the pickguard and is only connected by three wires to the body, I was thinking about making an EMG HSS setup.
I've got an idea for using plug connectors for the wires coming from the piezo, battery, and output jack. That way, I can easily swap the whole assembly without soldering when I decide to go back to the regular pickups.

Has anyone here made something similar? I'd be thankful to hear any tips you have.

[mmmguitar]

@vaya, assuming your Nitefly serial dates it to 2002, does it use the Fishman Powerchip (PCB-mounted pot, pictured below), or a different preamp?

When you say you got the piezo preamp working temporarily through "turning knobs", did you find that that turning the magnetic circuit volume and tone pots seemed to restore the piezo signal? Any photos you can post would also help.

I've experimented with various solderless setups. So long as whichever plug connectors you use for the job make a solid connection, there will be nothing to worry about. I will say, however, that I find soldering together a harness outside the guitar to be less stressful than trying to angle a mini screwdriver into a cramped control cavity to replace a stray wire with minimal length having found its way out of a solderless connector which I may have to remove the surrounding components just to get at. So my tip is to go with quick-connect plugs wherever you can, avoid any screw-fastened solderless connectors which aren't simple wire nuts, and to use soldered components for anything which will be mounted with minimal working room around it.

Being as you're working with a pickguard assembly, my main suggestion is to use a multimeter to ensure the new circuit components are all showing continuity where they should before installing it and tuning up - The frustration of having to work a loaded pickguard out from a guitar with the strings taught due to locking tuners will age you in dog years.

[vaya]

This is what the electronics look like:

Here is a close-up of the piezo preamp:

The gray cable from the output jack to the preamp could be a problem for a solderless setup because it carries three separate wires.

[mmmguitar]

@vaya, your guitar appears to have the NiteMix preamp with the mono/stereo push button on the pickguard (you can search "nitemix" within the Wiring Guides page to bring up a diagram).

The 9v negative (-) terminal in your battery box appears to be heavily oxidized and; because it's wired to act as the power on/off switch for any signal outputted from the guitar, will need to be cleaned and tested for continuity between the cleaned contact and where the wire eventually connects to the jack before you can move forward with troubleshooting the rest of the signal path.

Were you getting anything from the magnetic circuit or one side of the stereo path when toggling the mono/stereo push button next to the piezo volume pot, and did the piezo signal cutting out kill all output from the guitar, or only the piezo output?

[vaya]

@mmmguitar In both the mag only and mag/piezo positions, with the stereo/mono in both positions, I get the regular magnetic sound. When I switch to piezo only and the stereo/mono is pushed in, I sometimes get a faint white noise and some noise when tapping on the saddles, but not as loud as it should be. If the stereo/mono is not pushed in, no noise at all. I have the little pot on the preamp all the way to the right.

How do I remove the 9V battery case to clean the contacts? I see a screw that I can loosen, but I cannot easily remove the case.

[Patzag]

Gotta ask: Battery dead?

[mmmguitar]

How do I remove the 9V battery case to clean the contacts? I see a screw that I can loosen, but I cannot easily remove the case.

I haven't owned a Nitefly to say; so I'll instead point out that you can clean the battery terminals of the installed box by sticking a cotton swab down in there:

https://www.youtube.com/watch?v=z7ihHyBwyRU

I've previously cleaned corroded terminals/contacts by using one end of the swab to apply a baking soda/water paste, then the other end dipped in vinegar to scrub.

Your description of getting what sounds like the full mag signal through the preamp, but a weak or intermittent piezo signal, is a good indicator that it's working, but perhaps not drawing power from the battery sufficient to amplify the piezo signal up to spec. To add on to Pat's question, corroded terminals might also be reproducing the effect of having a nearly dead battery, if you've ruled the battery itself out.

As things stand, if you can confirm that the battery connections to the preamp and output jack have continuity, that might narrow the cause down to the old preamp or its pot (Di-Ya brand PCB-mount audio taper 2kΩ) needing serviced or replaced. I'm curious to see if the thread below yours with the same preamp ends up being the same issue.