Pickup measurement - strange issue

famous beagle

Well-known member
Hey y'all. I just bought a set of Fender Tex Mex pickups and haven't installed them yet. I was checking them with the multimeter just to make sure I was getting a reasonable resistance reading before I bothered with installation.

Two of them tested fine: one was 6.5k or so and the other was 7.3k or so. But on the third, I wasn't able to get a solid reading. It was showing around the 2Mohm range at first and was gradually (slowly) falling. It would never lock on though and is always showing WAY more resistance than expected.

I tried the cable and amp trick (touched one of the wires to the tip of a plugged in cable and the other to the sleeve and then tapped the pickup with a screwdriver), and it seemed to be working fine.

I was just wondering what could be causing the wacky reading?

I'm fairly certain it's not my equipment (meter) or method (i.e., touching the wires with my fingers while measuring) that's at fault here, as I did the measurements (of all the pickups) several times and got the same results.

Anyone have a clue?

Thanks
 
Hey,
A bad contact with the coil wire could send resistance sky high.
I'd reflow the solder joints at the pickup eyelets, unless they're new + under warranty.
 
^^^^^ What he said. ^^^^^ :D

Btw, welcome back beagle! Haven't seen you in a while.
 
Probably not a duff pup. Digital meters do not like inductors! Try shunting the coil with a resistor about equal to the expected resistance. That should damp the silliness and you can then calculate the actual value or say it is about twice the reading.

You will get the same nonsense when checking some transformers, especially big M power types. Trick there is to short out other windings as you go.

Takes me back! Trick for new kids in the service trade was to get them to check the Rs of a big mains traff with an Avo. All would be quiet then Faark!! As the lad got a jolt from the collapsing magnetic field!

Dave.
 
Probably not a duff pup. Digital meters do not like inductors! Try shunting the coil with a resistor about equal to the expected resistance.

But Dave......he's using the SAME meter on the other ones WITHOUT any silliness.
It must be a case of predjudice towards this one pickup. Lol :D

Shunting???? Never had to do that once like in never!

I've found a pickup reading funny, is the pickuo...or.....the battery on the mutimeter is almost dead or dying.
 
But Dave......he's using the SAME meter on the other ones WITHOUT any silliness.
It must be a case of predjudice towards this one pickup. Lol :D

Shunting???? Never had to do that once like in never!

I've found a pickup reading funny, is the pickuo...or.....the battery on the mutimeter is almost dead or dying.

Yes! It is a very random event. Depends I suppose on the pulse frequency of the meter, the inductance and the losses. I found one brand of PT would be fine but another FOR THE SAME AMP, would be silly!

For the want of a ~2k 1/2 watt, worth a try?

Dave
 
Might be (worth a try)
Pickups are funny. When assembling after winding the bobbin, you got these tiny tiny wires to solder. How the hell you gonna strip off the insulation on a wire the thickness of human hair? Lol

Ya burn it off with the heat from the soldering iron. Sometimes you have just enough heat to get the solder to flow, but not enough heat was generated to burn off the insulation fully.
I'll give it a helping hand by pulling the wire through 600 grit sandpaper folded in half.

I think he (famous beagle ) is running into that.
Well in a day or so, we'll get our answer, I guess.
:D
 
Thanks for the info y'all.

I'll probably just install them this weekend and see what happens. I was needing to change strings anyway. If it's not working, I'll come back to this thread and try some of the suggestions.
 
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