Need help w/ 80's Seymour Duncan - Did they change wire color start / finish ever?

[luffliffloaf]

Ha well maybe it's something someone hacked together? I have no clue. But the solder joints to the wires sure look original. The only thing suspicious is that little solder blob above where the braid is actually soldered... Also, the back plate is not threaded to the slugs. Is that normal? If you don't put the 4 mounting screws in, the back plate just falls off.

 

[Artie]

Well . . . people don't generally "hack together" a custom fit circuit board. Look closely at some of the lettering on that board, and "google" it, to see if you get any hits. It may be a cheap-ish import, or it may be some custom shop boutique pup maker. Either way, it's a good mystery.

 

[luffliffloaf]

Hey I just had a thought. Are the bobbins correct (pictured in original post)? Because if not, it could be someone else's pickup with the same four wiring colors as SD, with an SD backplate soldered on? Or something else like a pre-production or prototype?

I'll have to take it apart again and remove the large magnet and see if that board's marked under the magnet...

 

[Masta' C]

My interest is officially piqued. If you pull it apart, please grab more pics.

Even in their early actives and on their prototype tone circuits, SD usually had their name on their circuit boards.

To be clear, are you saying that you can't figure out how to get a DC resistance reading for each coil? Because that could provide additional insight.

 

[AlexR]

Additionally, the traces will lead you to what wire is what. The outside ones are more than likely for the same end of each coil. So if this is the case, they will either be the series connection or the hot/ground.

 

[ErikH]

The poles should not thread through the baseplate. That is normal. The 4 small screws are what hold everything to the baseplate. The wax is normal. That's done to prevent microphonic feedback.

Do this, connect the read and white together, set your meter to 20ohms. Put the probes on the black and green wires. What do you get back for a reading?

 

[PFDarkside]

Just a side note, sometimes experimentation is fun. Make sure the coils really are black/white and red/green with a multimeter. Tape red/white together, solder black, green and bare to a loose jack, plug in to an amp and hold the pickup up to another guitar and see what happens. It should be relatively hum free and in phase. Since the magnet must be “correct”, you’ll either get quiet and in phase or noise an out of phase. That’s how I test my Strat pickguards.

Of course relative phase to another, known Humbucker has to be confirmed but at least you’ll know what you’ve got.

 

[ErikH]

I'd like to see what the total DC resistance of the pickup is because that'll tell us if it really is a Screamin' Demon or an imposter.

 

[idsnowdog]

I believe someone used an SD baseplate to make whatever this is a trembucker. The color scheme for the wiring is coincidental.

 

[luffliffloaf]

Ok guys, here's what I've got: Please see the photos as well.

I had to heat the magnet up with my heat station in order to get it out. A lot of old wax everywhere. Being someone who restores other things (but is new to learning about the inner-workings of pickups), it does not seem to me that this pickup was ever opened up before or modified, other than the possibility of the back plate being added later, due to the solder blob. (Aside - Where is the wire braid on Screamin' Demon's, or SD's in general from this era usually connected, along the lip edge of the back plate, or on the flat part of the plate?)

The obverse of the circuit board is marked 412364 Rev A, as well as having some sort of symbol in the center and the number 10. I can see through the board to the reverse, which has a large mark in the center that appears to be some triangles and a large letter P.

When connecting the red and white, and testing the green and black, I get, as you can see in the photo, 10.39K ohms.

When looking at photos of other vintage SH-12's online, man the bobbins look the same, the red color wire that you can see through the leftmost holes is the same, etc.

Please help me understand this, because I'm an idiot:

As you can also see--and this is where I am still confused--the red and white wires go via the circuit board RIGHT end of the coils, and the black and the green wires are at the LEFT end of the coils.

But the black wire on the LEFT causes the analog meter (set to DC) to go up. But on the other coil, the red wire located on the opposite end on the RIGHT causes the meter to go up. What does this mean? Who is the start and who is the finish???

Thanks guys.

PS - so I take it I have to now learn how to re-wax pot this thing now as well?

 

[Masta' C]

I think this is worth emailing SD about directly, maybe even the Custom Shop.

The DCR is on par for the Screamin' Demon and the coils look legit, but the whole circuit board thing looks too well done (aside from the trimmed corners) to be unintentional. I wonder if this was indeed a prototype of something. Maybe SD was testing a new manufacturing process for the trembuckers, though I'm not sure what the advantage would be? Never seen anything quite like it...

 

[luffliffloaf]

Got any SD contact insider info that would be more likely to elicit a response, as opposed to just emailing some generic consumer email address?

As far as I can remember, this was in a Charvel Fusion 5, which was made between 1989 and 1991. I said 1987 in the original post, but I apparently was off by two or three years. Originally, looking online, that guitar would have shipped with Jackson J-90C humbucker in the bridge, and I--thinking back, trying to remember--had thought that my SD pickup was earlier than that and that someone put it in as a used pickup sometime later on. But as Masta C said previously in this thread, my pickup is from right there in that time frame from 91 or 90, so that does indeed coincide with the 89-91 time frame that the guitar was produced in as well.

So perhaps it came with the guitar new and was a special order. I don't know. The guitar was parted out and I may have the neck plate somewhere, but that's it, besides this SD.

 

[luffliffloaf]

I sent a message to the custom shop. We'll see if they get back to me.