SCN Bridge Pickup faulty from the factory

[One10]

Thank you, Gonzo id.

[Gonzo id]

Apologies if this is a double post (Or if I accidentally sent someone a message), I'm new to the forum.
I recently had an SCN apart and found these drawings from Bill very helpful.
http://www.billlawrence.com/Pages/Al...tm/Patent2.htm

[One10]

Before ditching it, you could do some simple practical tests, it could take as little as a piece of tape to fix.
Take off the cover and expose as much of the pickup as possible(if you can get to the coil tape remove carefully) . Have a good look around and see if you can see a sort somewhere. If no luck, then connect it directly to a jack and plug it into an amp (not too loud), with one hand tap the pickup with a small screwdriver to hear a signal, while doing that have a good poke around all over the pickup and try to find a point where it's breaking or making the short.
You might have no luck, but you might find a simple short that can be cleaned or insulated. Worth a go.

I have a look at it, I'll need to find a better magnifying glass first at a hobby shop. They are not wrapped in any tape, just bare coils.

GP

[jop120]

Before ditching it, you could do some simple practical tests, it could take as little as a piece of tape to fix.
Take off the cover and expose as much of the pickup as possible(if you can get to the coil tape remove carefully) . Have a good look around and see if you can see a sort somewhere. If no luck, then connect it directly to a jack and plug it into an amp (not too loud), with one hand tap the pickup with a small screwdriver to hear a signal, while doing that have a good poke around all over the pickup and try to find a point where it's breaking or making the short.
You might have no luck, but you might find a simple short that can be cleaned or insulated. Worth a go.

[One10]

I don't delve too deeply into testing pickups with LCR meters and the like, i prefer to do things by ear. Sounds like you're shorted to the ground. When you're getting 'no highs' it's just slightly touching, then no sound when it moves and makes good contact. That's the most common reason for the sound you've described.

ok jop120. Could be as you say. I suppose I will keep looking for another bridge SCN pickup as I would lose too much money just getting rid of the other two.

Thanks.

[One10]

There are PU fault conditions that change DCR, capacitance or decrease L. But I can't think of an effect that increases L by a factor of 4 other than doubling the turns number.

By "measuring error" I included misinterpretation effects of the LCR meter. Try this : Measure a guitar cable in the L range between tip and sleeve. Your meter will probably show a high Henry reading. Of course this is wrong, it's a misinterpretation of the cable capacitance by the meter. I just tried it with a cable having a capacitance of 264pF. In L mode my meter reads 96 Henry though there is zero inductance.

Ok Mr. Helmholtz, I have done that and these are the measurements:

A.) Cable has a capacitance of 345pF.

B.) Tip and sleeve measurement reads 5.179 Henrys in the mode setting as you requested.

GP

[Helmholtz]

Could the small voltage that a meter puts out in a resistance test cause a poor connection to behave differently?

I don't think so, especially as meter test voltages (several hundred mV) are similar to PU peak voltages.

[David King]

Could the small voltage that a meter puts out in a resistance test cause a poor connection to behave differently?

[Helmholtz]

Hard to imagine an intermittent problem that doesn't also change the DCR between the leads.

[jop120]

No, it doesn't sound like a pickup, no highs and works intermittently. Bill sure was a genius at pickup design, wasn't he!

I don't delve too deeply into testing pickups with LCR meters and the like, i prefer to do things by ear. Sounds like you're shorted to the ground. When you're getting 'no highs' it's just slightly touching, then no sound when it moves and makes good contact. That's the most common reason for the sound you've described.

[Helmholtz]

No and no, it also is not a measuring 'error'.

There are PU fault conditions that change DCR, capacitance or decrease L. But I can't think of an effect that increases L by a factor of 4 other than doubling the turns number.

By "measuring error" I included misinterpretation effects of the LCR meter. Try this : Measure a guitar cable in the L range between tip and sleeve. Your meter will probably show a high Henry reading. Of course this is wrong, it's a misinterpretation of the cable capacitance by the meter. I just tried it with a cable having a capacitance of 264pF. In L mode my meter reads 96 Henry though there is zero inductance.

[One10]

What exactly do you mean with "faulty from the factory"? Is it dead? If it is, the dealer you bought it from is responsible for the outcome. If it doesn't work, he is pretty much obligated to exchange it for another one, and and if he's not obligated to refund you, he's obligated to give you credit to purchase anything from the same value.

It doesn't sound like a pickup should and works intermittently. Unfortunately they don't have to, but I will talk to them again about it. Thanks.

search Bill Lawrence site, as he 'invented' the SCN's for Fender.
Does the SCN's sound good beside 16 times more Henrys?

No, it doesn't sound like a pickup, no highs and works intermittently. Bill sure was a genius at pickup design, wasn't he!

Must be a measuring error.
There is no fault condition that could produce such increase of (real) inductance. Was the PU connected to a capacitor during measurement?
http://zerocapcable.com/?page_id=210

No and no, it also is not a measuring 'error'.

Really the only things that can happen are a busted wire, a stretched wire, a cold solder joint, leads didn't get stripped or internal shorts in the coil. I suppose an easter bunny named "henry" could have been caught up in the winder and procreated for several generations.

One or more of those statements are probably true. Still would have liked to know how it is supposed to be wired up, in order to salvage it.

It has been pretty hard to find just a bridge SCN pickup, it's a shame Fender did not at least offer to scrounge one up at their headquarters, even if it was used.

1.) What is also odd, is that two of the pickups have all the pole pieces grounded, while the middle pickup has only the 'A' and 'B' pole pieces grounded, two out of six are grounded.

2.) I also have not seen such poorly wound pickups before in a supposed 'quality' brand. One was wound so poorly, it was coming over the side of the top plate, or plates and the wires were kinked up from when the person pushed the pickup cover over the pickup (the windings did not fit in the prescribed area as designed). I had to gently push them back on to the side of the pickup and then glue them in place or they would have torn off completely when reattaching the pickup cover.


Thanks for the quick replies everyone, I was delayed in my responses due to Uncle Sam getting my complete attention during the 14th. and 15th. of April.

[David King]

Really the only things that can happen are a busted wire, a stretched wire, a cold solder joint, leads didn't get stripped or internal shorts in the coil. I suppose an easter bunny named "henry" could have been caught up in the winder and procreated for several generations.

[Helmholtz]

Must be a measuring error.
There is no fault condition that could produce such increase of (real) inductance. Was the PU connected to a capacitor during measurement?

http://zerocapcable.com/?page_id=210

[dodona]

I cannot find anything on the internet explaining how these types of pickups are made, or exploded views.

search Bill Lawrence site, as he 'invented' the SCN's for Fender.
Does the SCN's sound good beside 16 times more Henrys?