NiteFly SA Noise from Piezo

[TexasJim]

I have stock NSV/SA I've had for over fifteen years. The serial number is 012121 USA. Black, with H-S-S pickups. When I select the piezo pickup, or the "both" position, it sounds like a thunderstorm is going on in my amp. The mag pickups function normally. It's probably something in the Powerchip, but where do I start to diagnose this, without just throwing parts at it? Solder joints? If the Powerchip is the sole problem, I don't mind buying one. BUT, is the currently available Powerchip the same as mine? Mine has the original rectangular switching jack. Will it hook direct to the new Powerchip, or do I use the new jack with the Powerchip?

I've been looking for a Parker Forum for years, and was pleased to find the site. I've already learned a lot, just reading the posts.

Thanks, TexasJim, on the Texas Riviera.

[mmmguitar]

Welcome, @TexasJim. Would you be willing to post a photo of the pickguard flipped over; so we can have a look at the situation under the hood? It sounds like a wire's been disconnected from one of the components in your piezo circuit. The basic signal path is

piezo element leads summed to underside of bridge > input of powerchip > on/off/on switch in parallel with preamp and piezo volume pot > stereo switch lugs,

with each ">" being wire-bridged solder points you can use a multimeter to check for continuity between.

Because the magnetic pickup signal path is series-connected into the powerchip via the on/off/on switch where your "mag only" selection seems to work, it doesn't seem like a battery connection is broken (the Powerchip is an active buffer circuit; which will only output a signal when powered).

Assuming your components are all passing the signal along to the jack as they should, your issue is more likely to be a broken wire connection than anything else. You wouldn't need to replace the jack unless the jack was the point of failure.

Unless I'm suffering the ill effects of a brain fart, your guitar should essentially be wired up like this: download/file.php?id=841&mode=view

#PiezoIssues

[TexasJim]

Thanks, mmmguitar. I'll do a lobotomy on my Nitefly tomorrow and take a pic. I should have also noted that, even though the piezo sounds like a thunderstorm, it still plays whatever notes I'm playing on the guitar. I just have a loud, background of static behind my guitar notes. Also, if I use a stereo cable out to two different amps or channels of an amp, the mag pickups function normally, but the piezo feed has the thunder. If I gang them(both), the noise is in the mix. It has always sounded to me like a capacitor breaking down. I don't know if there are any, but that's what it sounds like to me. I left the guitar plugged in at max, to see if it would "burn in", but after many hours, no change.

I'll be back, TexasJim

[TexasJim]

mmmguitar: I finally got the pickguard off my NiteFly-SA. It is a "new"NiteFly-SA, made in 2002(I think), and the P-38 schematic is "similar". ZSome wire colors are different, and mine has the 5-wire humbucker. The hand-written note on the schematic does not seem to be the way mine is wired. The five wires are: green and bare ground both soldered to the mag. vol. pot. case, black & white wires paired and soldered to the first lug on the 5-way switch, and the red wire is soldered to the 4th lug on the 5-way, counting from the neck end of the pickguard.

There is a long red & black paired wire wound round and round, with the red soldered to the center lug on the mag vol pot(which also has a black wire going to the tone pot) and the black wire is soldered to the mag vol pot case ground. The other ends of the red & black wire look like they were cut off and never soldered to anything. It was just rolled up and stuck between the 5-way switch and the tone pot?????? Strange.

I see no obvious broken wires, no cold solder joints. The output jack wires to the Powerchip show continuity(which I expected, since all the pickups work and produce sound, with just the piezo having the background thunderstorm). The wire from the piezo bridge to the powerchip seems to be a tiny coaxial cable, with the shield soldered to the Powerchip ground, but there is no obvious core wire going anywhere(???). The shield is continuous, and seems to have never had a wire out of it. Also strange.

I don't think this pickguard has ever been off. I bought the guitar used about 15 years back, and it played normal until about two years ago. When I got it, the tool bag hadn't even been opened! I see that there is a long and a short version of the Powerchip for sale, and would you know which I have? I don't mind buying one, but I'd like to know if something else is causing the thunder. I personally think all is well with the piezo, the wiring and switching, but you may have other ideas. Glad to have someone to consult on these kinds of problems.

I tried to attach pics, but it said my pics were larger than the 3 mb limit. I could e-mail them. Thanks again, TexasJim

[mmmguitar]

I tried to attach pics, but it said my pics were larger than the 3 mb limit. I could e-mail them. Thanks again, TexasJim

Photos would be most helpful. The braided black and red wires that aren't connected to anything at one end are a bit of a head-scratcher in text. In the Parkers I've worked on, those are most commonly the battery wires - But them being soldered to the vol pot suggests that your main ground wire (black) is disconnected and causing the signal noise, with the red from the mag vol output supposed to go to one lug of the mag/mix piezo switch (it should share the lug with another wire carrying the signal on to the preamp input).

There are free image resizer sites and programs out there.

[TexasJim]

Sorry. I think I've downsized both. TexasJim

[mmmguitar]

Thanks, @TexasJim. Though It's still pretty hard to parse all that spaghetti, it looks like someone (at the factory, presumably?) soldered in extra wires (the loose ends of that red and black pair would be soldered to the tip and sleeve lugs of the output jack in the event the preamp needed to be bypassed). As you said, the mag/mix/piezo and Powerchip wires appear to be wired up correctly. If there's continuity between all the grounded components (strings, trem claw, pickguard shielding, pot and switch casings, ground sleeve lug at jack, etc.), then that may narrow the fault down to the preamp. I'm afraid I'd need the guitar in front of me to determine any more from the info we seem to have, so far.

That extra pair of wires has my imagination running wild - I wonder if someone previously tried isolating the circuits to diagnose a fault differentially?

In response to all the other details you helpfully mentioned: By the colors you described, the Dimarzio humbucker is wired correctly. That coaxial cable for the piezo lead should go from the summed piezo elements soldered to the underside of the bridge to the input of the preamp. And any version of the Powerchip with the same blue trim pot on the underside should work as a replacement (the PCBs simply got a smaller footprint with each iteration).

Your symptom of cacophonous noise "behind" the signal indicates that the preamp is amplifying signal noise that isn't being grounded prior to the input stage. So I wonder if there's grounding continuity between the saddles, element summing point on the underside of the bridge, and the trem spring claw. Of course, this could end up being one of those gremlin situations where "IT MUST BE THE SPRING CLAW - IT'S ALWAYS THE SPRING CLAW!" simply fails to pin it down; and we get more investigation to do. Are the red and black battery wires coming into contact with any signal-carrying wires when everything's tucked back in the cavity? Is there just as much signal noise with the pickguard out of the guitar as in?

[tronathan]

Thanks for this post folks. I believe my early ‘04 mojo is experiencing the exact same problem, which just started today and was not present a few days ago. although I would describe the sound as a dirty record player…..

[tronathan]

… and just like that, the thunder(dirty record spinning) sound is gone. Whatever was out of whack must have snapped back in… or perhaps some cosmic static in my house stopped after a couple days. Didn’t change anything- I opened the guitar up to take a look and fiddled around but the static seemed persistent and unchanged by changing the orientation of wires, battery case etc.

I worry it will come back but for now it’s disappeared. I know this isn’t helpful towards a clear diagnosis, but perhaps a ground or something is just loose and it fell back into place.