Troubleshooting a Dimarzio Fasttrack 2 low output

[giantlaser]

Hello, 

I learned how to read the DC restitance value from a multimeter out of the pickups from the lead wires. I don't understand why higher resistance means more output but that's besides the point. Just want to let you know how much of an amateur I am

So yes I have this fasttrack, which on the website is supposed to read a heaving 18.07 Kohms. Only to be reading about 10k on my multimeter. With other pickups I've been able to read values that corresponded to the ones on the specs sheet for the record!

So yes, frankly, I wouldn't have the slightest idea on how to troubleshoot and issue like this. 

Cheers,

    

[newey]

GL-

Those readings are quite discrepant. There's a good deal of variation from the factory on resistance values, but not by that much. Which suggests that there may be a short in the coil at some point.

I am assuming this is wired in standard HB fashion, with the coils in series?

[Deleted]

Feb 8, 2016 22:45:48 GMT -5 newey said:

GL-

Those readings are quite discrepant. There's a good deal of variation from the factory on resistance values, but not by that much. Which suggests that there may be a short in the coil at some point.

I am assuming this is wired in standard HB fashion, with the coils in series?

+1. It only points to parallel wiring with one coil circuit open or just shorted to ground. Also the OP needs to say if he measures the pup dismounted from the guitar's wiring or not. Inside the guitar other factors might plat some role (like damaged low resistance vol pot).

[giantlaser]

Also the OP needs to say if he measures the pup dismounted from the guitar's wiring or not.

Yes the PUP was measured outside the guitar.


I'm afraid I'm too impaired to fix a short though, or even properly understand what a short acutally is for that matter. Yes I looked it up but really struggling to understand..... Wondering if there is anything I can still do with it.

[newey]

Before drawing any conclusions here, why don't you measure the coils individually? That might disclose a problem with one or the other. The DM website doesn't give individual resistance figures, but it's probably safe to assume that the coils are roughly similar.

[sumgai]

Mar 9, 2016 23:09:58 GMT -5 newey said:

'T'ain't necessarily so.    It's entirely possible to buck hum with dissimilar coils. All one needs is for the reactance to be roughly equal between the two, which of course depends on a host of factors, and the hum will be greatly reduced.

I'm thinking that if the entire pickup is supposed to read 18KΩ DC resistance, and we're reading only 10KΩ, then it's well within tolerances to assume that one of the two coils is partially or wholly shorted.

gl, let me ponder a bit on how to write up what I think you need, in order to understand the underlying concepts here. For now though, take it as an Article of Faith that when a coil is shorted out, it produces no sound at the output.  We sometimes take advantage of this in our wiring schemes (selecting which coils and/or which pickups), but when it's shorted out all of the time?  The technical term for that is: A BAD THING.

sumgai

[Deleted]

I have this pup and have it in series/parallel switching. I will give both measurements in the evening. From that we have two equations with two unknowns, piece of cake for giantlaser to figure out.

[Deleted]

Parallel : 4 Kohms
Series : 16.4 Kohms
(measurements inside the guitar with 500K pots)

by the looks of it seems pretty symmetrical. (which is manifested by the zero hum, e.g. in comparison to the unbalanced EMGs)

[giantlaser]

For now though, take it as an Article of Faith that when a coil is shorted out, it produces no sound at the output.

I think I can wrap my funny mind around this one though, makes sense that the current doesn't really pass through the coil to begin with, so I can assume I can think of "short" in terms of "shortcut directly to the lead wire"?

Anyways, not at home for the moment but will do coils separately and post values. 

Special thanks to greekdude for publishing what he read with the same coils.

Do you know what's really funny: befor I figured I wanted to venture into guitar electronics I was always disappointed with my Dimarzio fasttrack in my stratocaster, leaving me to the conclusion that single coil sized humbuckers can never sound juicy fat and thick like a real humbucker bacause they wouldn't be the real thing to begin with.