Need help checking the voltage on an old pickup

[The Vault]

Here's my situation. I sold an old Seymour Duncan JB to a local music store that deals with vintage guitar gear. They have a reputation for ripping people off/short changing them. I think he may have hustled me out of my pickup.

Here's the story: The guitar shop repairman was checking the voltage right in front of me and tells me that one of the coils was dead. This came as a surprise to me because both coils had were working when I took the pup out of my LP last week. I ended up selling it to the store for $15 because he said that only one of the coils wasn't working and that it wasn't worth it for him because it would cost $30 to fix. In hindsight, I think the guy didn't check the proper color-coded wires.

Here's my question: Which color wires are supposed to be checked for voltage reading on a Seymour Duncan JBJ (from the 80's)? I believe they are the same as new JB's.

This has me in a real knot. If I find out that they hustled me I am heading straight back to the store to give them a piece of my mind.

Tv.

 

[WICKED LESTER]

Re: Need help checking the voltage on an old pickup

the pup should have a resistance 16.4K
it may be a little higher or lower but in the 16K-17K range
I had one JB that was 17.3K and one that was only 15.9K
the voltage is a lot harder to check and actually it is MILLIVOLT
the only passive pup that goes to 1 volt is the dimarzio X2n!
1000MV's = 1 VOLT

 

[Artie]

Re: Need help checking the voltage on an old pickup

If its a 4-wire conductor, he should look for resistance between the black and white, and then again between the green and red. Each should be approx. half of what wicked said, or 8.2k.

 

[The Vault]

Re: Need help checking the voltage on an old pickup

hmmm... He checked the red and green and it did show apx. 8k...

Than he checked the black (without the white wire) and it read less than 1k... that was the coil he said was dead. But he didn't check both the white and black together.

I think I was hustled. Not sure how to deal with the situation now that I think so.

Tv.

 

[WICKED LESTER]

Re: Need help checking the voltage on an old pickup

hmmm... He checked the red and green and it did show apx. 8k...

Than he checked the black (without the white wire) and it read less than 1k... that was the coil he said was dead. But he didn't check both the white and black together.

I think I was hustled. Not sure how to deal with the situation now that I think so.

Tv.

the dude ripped you man! :yell:
NOW GO GET EM and put em six feet under!!!! :fing2:

 

[Artie]

Re: Need help checking the voltage on an old pickup

hmmm... He checked the red and green and it did show apx. 8k...

Than he checked the black (without the white wire) and it read less than 1k... that was the coil he said was dead. But he didn't check both the white and black together.

I think I was hustled. Not sure how to deal with the situation now that I think so.

Tv.

Remember, its not "together". Its one meter lead on green, and one meter lead on red, not holding them with your fingers. (You can hold one, but not both.)

Then its one meter lead on black, and one meter lead on white. Thats the wires for the two coils.

 

[The Vault]

Re: Need help checking the voltage on an old pickup

Hmm.... I was hustled. What was funny was that when I went to the cashier, he was on the fone with the repair guy who was telling him to give me my $15. The cashier was smirking and because I know rip people off to begin with I said, "What's so funny?" He didn't reply and shrugged his shoulders while giving me my money. Than I said, "I know you guys underpaid me and are gonna jack the price up to $80... have fun ripping off your next customer." Needless to say, his face went blank knowing exactly what I was talking about.

I think that I will go in and ask to check the voltage again, but they've got my cash. There isn't much that can be done other than go on the local musician's buy and sell website that EVERYONE in my city goes on and share what the store did.

But I don't wanna resort thier level... but on the other hand, I don't want these guys to continue ripping people off.

Decisions, decisions.

:smoker:

Tv.

 

[Zhangliqun]

Re: Need help checking the voltage on an old pickup

DC resistance is all you need to check to see if a pickup is working or not. Don't bother with voltage.

As has been said, something in the 16-17k range is what you should get for a JB, assuming the two coil-junction leads are still soldered together. If they are not still soldered together, you should get either 8.2 for either coil or a reading that looks like you're measuring a pot, several hundred k to up in the "megs", possibly the "infinite" reading (my meter says "UL" or something like that one it gets an infinite). This would mean that you are reading a lead from each coil and since they are not connected, you get a really high resistance reading because the two coils are not connected.

If on the other hand the two coils ARE still joined (probably so since you just pulled it out of your guitar) and you get:

1) A high or "infinite" reading, then one or both of the coils has a problem, though unless the coil itself is damaged, it's usually pretty easily fixed. It probably means may be that the coil wire broke off from the lead. Pull all the tape off and check to see.

Even if it turns out the coil is damaged, you may be able to salvage the pickup if the short or break in the coil is fairly shallow. Unwind it until you can get a good reading on it. This happened with a Strat pickup I had -- like the mega-dufus I sometimes am, I accidentally poked the coil with an Exacto knife. It was originally 6.3k but I unwound it until I could get a good read on it. It was 5.75k at that point, meaning it wouldn't sound the same, but my intent was to add a bunch of turns anyway, I just had to add about 600 more than I planned. It's now 7.3k with a tap at 5.75k.

2) Zero reading -- there is a short. Maybe the hot lead is touching the baseplate or something. Measure the hot lead on one probe and that bare wire shield lead on the other. If it's still zero, there's a short somewhere.

3) 8.2k (plus or minus for a JB) reading -- one coil is shorted or disconnected or something and you may be reading the lead from one coil with the coil junction lead(s).