Do Pick-ups go bad? Technical help needed

[swhiteh3]

Can a pick-up go bad over time? One of my favorite guitars went unplayed for a few years - an original American made Vivian Campbell / Kramer Nightswan. The guitar has a Seymour Duncan Full Shred pickup in the bridge position, and a Seymour Duncan JB in the middle position (nothing in the neck position - a unique look).

Since it's been a while since I've played it, I've forgotten exactly which way the 3-way switch works, but clearly one pick-up is not working right (and I *think* it's the JB). When I switch the 3-way to position 1, I get a normal sound, position 2 (the two pickups combined) sounds just like channel 1 with just a little more tin top-end. In position 3, I get the thinnest most disgusting sound you can imagine with maybe 1/10th of the volume of the other pickup. It's very quiet and very frail. Basically, completely unusable for anything other than a creepy special effect.

So, first, any idea what happened?

Second, how can I tell for sure, when I'm in any given position, which pickup(s) is/are active?

Finally, is it likely an electronics (ie wiring, pot, switch) problem or a problem with the pick-up? My guitar tech told me (before I knew about this issue) that he could re-wire the whole thing with all new pots and jacks for about $70, and since it needs that anyway (scratchy volume pot and the jack is starting to go bad) I'm tempted to give it to him and see if the re-wire fixes it. Is that realistic or hopelessly optimistic?

Thanks for any opinions or tech provided!

-Scott Whitehead

 

[Rocky]

Check your solder joints. Chances of it being a pickup going bad are pretty slim.

 

[aberrant]

I'd check the soldering on the switch. If you're getting a slightly altered sound on the second position and the third is out, I'd guess at the switch first.

 

[MopHead]

yeah id have to agree, more likely for that switch to die than the pickup start there.,
Maybe something came loose?

 

[Anonymous]

of course pick ups can die a "sudden death"

there are many - especially - fender vintage pups where this is common. the insulation corrodes with the years, temperature changes and aging do their jobs as well. contact to the magnets etc.

gibson humbucker are less sensible but are dying also ... as i heard ;-)

here from a fender forum:

Why do Vintage Fender Pickups Die?

After many years of use, Fender pickups die much more regularly than any other brand of pickups. Even Gibson pickups from the 1930's don't die like Fender pickups from the 1950's. Actually, the reason has to do with the design and materials of Fender pickups themselves.
Since the windings of older Fender pickups are in direct contact with the magnets, this has caused some problems. With time, the magnets seem to chemically react with the windings/insulation, causing the windings to break. Once a single inner-most layer of winding is broken, that's it; the pickup is "dead". Due to magnetic fields, the pickups may still work, but it will sound extremely thin and weak. Also, if you turn down the Tone control to that pickup, it will go complete dead and silient. That is a sure test of a dead Fender pickup. You can also measure the Ohms of the pickup. Dead pickups will register "open" (no resistance). But because the pots are in-circuit, an open pickup may read some bizarre high resistance, and the value may bounce up and down (again, due to the magnet properties of coils and the pots in the circuit). You should do the Ohm test right at the pickup leads, and to do it right, have one lead disconnected from the circuit (but please don't desolder any vintage guitar pickup leads!) Also the position of the pickup switch can effect values too, as can your fingers if they are touching the meter's probes. Just keep that in mind.

Another thing that kills old Fender pickups is someone trying to "adjust" the (non-adjustable) pole pieces (magnets). Because of the lack of a wound third (G) sting, some musicians push the G string magnet down through the flatwork, moving it further away from the strings. The problem is this can tear the inner windings. Since the magnets are in direct contact with the windings, and the magnets are sand casted and have rough sides, this will easily tear a winding. One torn winding will create a dead pickup (see the paragraph above).

Newer Fender pickups have been able to avoid both of these problems. Now, after the magnets are installed in the flatwork, lacquer is sprayed over the magnets and flatwork. Then the wire is wound around the magnets. This means the magnets are no longer in direct contact with the inner windings. Therefore, if the magnets are pushed thru the flatwork, they are less likely to tear the windings. Also there is less chance of a chemical reaction between the magnets and windings as they are insulated from each other by the lacquer.

 

[Rocky]

Another thing that kills old Fender pickups is someone trying to "adjust" the (non-adjustable) pole pieces (magnets). Because of the lack of a wound third (G) sting, some musicians push the G string magnet down through the flatwork, moving it further away from the strings. The problem is this can tear the inner windings. Since the magnets are in direct contact with the windings, and the magnets are sand casted and have rough sides, this will easily tear a winding. One torn winding will create a dead pickup (see the paragraph above).

A person forcing the pole piece is NOT part of a pickup 'just stopping' rather it is an example of a person breaking a pickup.

Not the same thing at all.

Pushing poles around can screw up windings on any single coil. Most importantly here...the guy is talking about Duncn humbuckers not Fender singles.

His issue is not likely to be an internal pickup issue

 

[domct203]

Get yourself some Caig Labs DeOx-It and clean your pots, jack and switch contacts. It will be way cheaper, and should do the trick. I'm thinking the switch contacts are just as dirty as the scratchy pots and switch.

Unless you're pulling on the wiring, or if they were poorly done to start with, the solder joints should be OK.

Dom

 

[swhiteh3]

Thanks guy for all the input!

If anyone can comment on my question about how to determine which pick-up is active, I'm still interested in that.

As for the De-Oxit, I actually have some (and I also have the Pro-Gold from Caig, which is meant as a finer cleaner for surfaces that are not as oxidized). I use them all the time in my race-car on electronics. Why I didn't think of using it on the guitar, I have no idea. So do you just "spray down" the entire switch or pot while actuating it? I use it on contacts all the time, but rarely on components with contact surfaces like switches.

I had never heard of a pick-up failing, so I'm glad to hear that *in general* that's the case.

If the De-Oxit doesn't work, I'll let the tech re-wire the entire thing with new switches - and I'll assume that will probably take care of it.

 

[lesterpaul]

you can grab a screwdriver and tap on the pickups while moving the switch from position to position while all hooked up-if poition 1 is bridge only, then the bridge pup will make a popping sound while you tap on it and the middle pup will not-is this what you are referring to?(forgive me if I am off base...)

 

[swhiteh3]

you can grab a screwdriver and tap on the pickups while moving the switch from position to position while all hooked up-if poition 1 is bridge only, then the bridge pup will make a popping sound while you tap on it and the middle pup will not-is this what you are referring to?(forgive me if I am off base...)

Thanks. I tried this and it doesn't seem to give me a definitive answer. I'll just open up the **** thing and get out the voltmeter....

Thanks!

 

[lesterpaul]

hmm...yes..sounds like something is amiss(geez...iszat even a word??)

 

[swhiteh3]

Well, I finally got around to working on the guitar.

I de-soldered every joint inside the main cavity and re-soldered everything, including all the grounds, the connections to the pickup switch and volume pot, and the series links for each pick-up. I also gave everything a good splashing of De-Oxit Pro-Gold.

The good news is that the noisy/scratchy volume pot is fixed. That spray really is amazing.

There were several cold solder joints, and one joint had been over-soldered, and the solder had worked it's way too close to the insulation, and it was about the break anyway, so I'm glad I did this.

However, the SD JB is still weak. I was able to trace it and it's definitely the JB. Oddly, it's not as bad as it was before, but it's still not right. WAY bright without enough gain.

As I'm writing this, I thought of a test. I could short across the pickup selection switch to see if that helps the sound. If it does, I know I need to clean the switch better, or replace it. Back to the garage....

 

[swhiteh3]

Contacts across the switch read as low as 1 ohm, with the majority of that resistance coming from the connection between my test probe and the contact, as best I can tell, so I'm pretty sure the problem is not the switch.

Also, in re-tracing the wires - I was wrong. The JB pick-up is the one that's working, and the Full Shred pick-up is the one that is NOT working properly. I had made the wrong assumption about the way the switch operated. And now that I've tested the switch, I found the mistake.

I found a wiring diagram that is exactly the same as my guitar, and I checked every last wire one more time. With two humbuckers, one volume, and only a simple 3-way, it's as simple as it gets!
HERE: http://www.seymourduncan.com/support/wiring-diagrams/schematics.php?schematic=2h_1v_3w

I re-set the heights of the pick-ups to 3/32", as recommended by S/D.

Is there a convention that should be followed as far as which side of the pick-up goes toward the bridge and which side goes toward the neck? Could that possibly be the problem? In the picture of the Full Shred pick-up (see links below) the bridge would be toward the bottom of the page, with the "window" into the copper windings toward the LOW E string. The JB is the opposite - the "window" is toward the HIGH E string. Does this matter?
http://www.guitarelectronics.com/pr...l_Shred_Bridge_Position_Humbucker__Black.html
http://www.guitarelectronics.com/product/SH4B/Seymour_Duncan_JB_Model_Humbucker__Black.html

The best way I can describe the sound is out of phase. It's quiet and body-less. Bright and cold.

But, I think I've found the nail in the coffin. According to Seymour Duncan's website, you can measure the impedance across the pick-ups to determine their health. The JB measures 16.4kOhm, just as expected. The Full Shred shows no continuity - none at all. Time to replace the pick-up. DOH!