Pickup Check-Off List.

[Stratz]

I would measure and record the inductance and AC resistance at 1 KHz. If the AC resistance is out of line, it's likely that a coil is shorted; this is not detectable from the DC resistance.

Joe, What is considered to be "out of line"
The AC resistance of any coil (or even just a long length of magnet wire) I have ever measured with the Extech @ 1khz is always higher than my DCR meters read. I get a much closer match with the Extech set @ 120hz.

[Joe Gwinn]

Joe, What is considered to be "out of line"

Probably 10%, but best settled empirically: Measure the values of the pickups you make, and compare values of a given pickup design. Over time, you will see what the normal spread is, and so will be able to tell if one value is too far from the crowd. A listening test should tell if the outlier is random, or due to a short (which will make the pickup sound dead).

The AC resistance of any coil (or even just a long length of magnet wire) I have ever measured with the Extech @ 1khz is always higher than my DCR meters read. I get a much closer match with the Extech set @ 120hz.

The AC resistance is the sum of the DC resistance plus the loss due to eddy currents (including shorted turns). The lower the test frequency, the lower the eddy current loading, and so the closer Rac will be to Rdc. It's the excess of Rac over Rdc that tells the tale, and the higher the test frequency the larger the difference (so long as one remains well below resonance).

So, to detect shorted coils, it's best to test at 1 KHz (not 120 Hz).

[big_teee]

Pickup Check off List PDF

I combined the Single and Humbucker checkoff, and made a spreadsheet.
I will post it on the Resource Thread later.
If you see a mistake let me know please?

[kayakerca]

I combined the Single and Humbucker checkoff, and made a spreadsheet.
I will post it on the Resource Thread later.
If you see a mistake let me know please?
[ATTACH]21575[/ATTACH]

When I try to download the document, I get pushed off to this error message:

"Invalid Attachment specified. If you followed a valid link, please notify the administrator"

[big_teee]

When I try to download the document, I get pushed off to this error message:

"Invalid Attachment specified. If you followed a valid link, please notify the administrator"

Try again.
I deleted the first one, and replaced it.
You were probably doing it when I had it deleted.
I left off a item and redid it.
Sorry,
T

[Stratz]

Probably 10%, but best settled empirically: Measure the values of the pickups you make, and compare values of a given pickup design. Over time, you will see what the normal spread is, and so will be able to tell if one value is too far from the crowd.

Thank you Joe. That was a very informative yet simple explanation.
I've had the meter for quite a while but never understood why the readings were different. Now I have another variable to watch for.
Last night I tested a 10K resistor (5%) and it was in range on both the 1k and 120hz settings.

Thanks again!
Rob

[Joe Gwinn]

Thank you Joe. That was a very informative yet simple explanation.

Welcome.

I've had the meter for quite a while but never understood why the readings were different. Now I have another variable to watch for.
Last night I tested a 10K resistor (5%) and it was in range on both the 1k and 120hz settings.

With a resistor, Rdc and Rac will be equal, to within the accuracy of the test equipment.