Jazz bass, how to test if the pickup is dead

[Daisuche]

Hey guys,
there're quite a few posts about pickup issues but I'm not sure I found anything about my question. Sorry in case this has been already discussed.

I have the neck pickup of my '73 jazz bass no longer responding, it's like the volume knob was zero all the time. I did the usual first step of the troubleshooting: tapping on the pickup with a metal object, nothing, all dead. So I opened it and measured with a voltmeter, but I didn't want to unsolder all the electronic. I understand that the best test would be done measuring the ohm on the pickup when it's disconnected from the rest of the circuit, but I'd prefer not to do it at the moment. All the soldering seems great to me, at a visual check.

So I measured the ohm and it's 7 ohm on both pickups. All the measures I made report the same results on both pickups, but one works and the other doesn't. But again: my measurement were made with all the electronics fully assembled.

Sorry for the long post... my question is: what resistance (ohm) do you expect to measure when all the circuit is assembled? If I measured 7 ohm, doesn't mean that the pickup is ok?

Any suggestion?
Thank you all!

 

[HG1180]

Yes, 7 Ohms is a normal reading for a single-coil type pickup, however to get a reading true to that pickup it is necessary you desolder it.

Being that the pup is over 40 years old I would check the wax potting, Lead wire connection to the windings, any breaks in the winding itself, and continuity between the windings and lead wire.

I had a set of P pups that mysteriously went dead and it ended up being the pot it was soldered to despite having the J pickup (PJ bass) still remaining functional, albeit with no volume control.
So, this being said make sure your pots are functional.

If everything tests normal, and the pots are functional but nothing is working still, go ahead and reheat and flux all of the solder joints along with spraying some contact cleaner into the pots and output jack.

Good luck!

 

[Jared Houseman]

Sounds like your pickups are fine try alligator clipping a jack to each pickup and play them. Then clip to the out put of your volume pot, then to your tone pot, then to your output jack. Eventually you'll find where ever the problem is

 

[Tank88]

Sounds like your pickups are fine try alligator clipping a jack to each pickup and play them. Then clip to the out put of your volume pot, then to your tone pot, then to your output jack. Eventually you'll find where ever the problem is

+1 This will narrow down the problem without having to mess with how the setup is currently wired.

 

[BenJuan26]

I'm here from the future to say that this helped a lot!

I have an early 2000's Squier 5-string "P-bass" (the weird ones that have jazz-style pickups). I don't think the bridge pickup ever worked, and I was just too inexperienced early on to really understand that that's what was happening. (I had a volume knob and a tone knob, what was the middle one for? ‍) I've been listening to a lot of Joe Dart lately and it's really made me want to get that pickup working. I actually took it apart last year and nothing seemed amiss, so I gave up.

I found this post and decided to try desoldering, checking the resistance, and alligator clipping directly to the output to know for sure what was failing. The resistance looked fine, and when I clipped it to the output, I had sound! I thought that the knob must be bad for sure. After testing a bunch of connections, it seemed like everything should have been working, and after reflowing the solder on the knob output, it actually worked. All these years, and it was a cold joint causing the problem.

 

[Jim C]

Yes, 7 Ohms is a normal reading for a single-coil type pickup, however to get a reading true to that pickup it is necessary you desolder it.

Being that the pup is over 40 years old I would check the wax potting, Lead wire connection to the windings, any breaks in the winding itself, and continuity between the windings and lead wire.

I had a set of P pups that mysteriously went dead and it ended up being the pot it was soldered to despite having the J pickup (PJ bass) still remaining functional, albeit with no volume control.
So, this being said make sure your pots are functional.

If everything tests normal, and the pots are functional but nothing is working still, go ahead and reheat and flux all of the solder joints along with spraying some contact cleaner into the pots and output jack.

Good luck!

How could 7 Ohms be normal for something that normally measure 7,000 Ohms?
The pup needs to be electrically out of the circuit in order for the DC resistance measurement to have any meaningful info.