Pickup works/measures open

[lowell]

Hey all,
I've got a HB pickup from 1980 Les Paul. Not sure if stock or not. The thing works but sounds quite weird... trebly and loud. When I measure the DC resistance it is open. I restripped the wire to be sure I had a good connection w/ the meter and still OL. ??

Oh and when the pickup chassis is touched when plugged in there is a lot of hum.

[NightWinder]

...

Hey all,
I've got a HB pickup from 1980 Les Paul. Not sure if stock or not. The thing works but sounds quite weird... trebly and loud. When I measure the DC resistance it is open. I restripped the wire to be sure I had a good connection w/ the meter and still OL. ??

Oh and when the pickup chassis is touched when plugged in there is a lot of hum.

Sounds like a finish wire came off the lead in the coil, which would be ungrounded as well

[lowell]

NW,
Could you explain how to go about investigating this? Do you mean the "finish" end of the magnet wire is disconnected from the "lead" that connects to the volume pot? Also, what is ungrounded? thanks.

[David Schwab]

He means the end of the coil. The "start" is the inside or beginning of the coil, and the end is the "finish". At the end of the coil wire is the "lead" which then attaches to the hookup wire that goes to the volume control.

The end of the coil might have come lose from the lead. If that's the case it can be fixed. If the start is broken you will have to rewind the coil.

[lowell]

must be the start of the winding.... darn haven't built winder yet. So the pickup would still work if the start was open?

[Possum]

...

yeah, the coil is still generating current when you play and some of it is getting through, the higher frequencies especially. If its the coil end you can resolder the coil end to the lead off the wire. If you measure each coil you'll find which one is dead. Take it out and very very carefully take the tape off, sometimes using naptha (lighter fluid) helps remove the sticky stuff, go really slow, if you break the start of the coil which is real easy to do then your pickup is a goner and will have to be rewound. Use your ohmeter and measure from the coil start to the coil finish, which will be the magnet wire that you can unwind from the coil. unwind a bit of it, sand off the insulation with 400 grit sandpaper and see if you get a reading, if you do then solder the lead back on and carefully tape it all back up. If you don't get a reading then there's a dead break in the coil inside somewhere and you'll need to rewind it.

[David Schwab]

Oh and when the pickup chassis is touched when plugged in there is a lot of hum.

I just read this part. To me that sounds like one of the finish leads is touching the baseplate. Does the pickup have a cover on it?

It might just be a broken connection to a lead wire where the hot end of the cable is connected.

Some times people take the covers off and put them back on and brake things.

[SK66]

I just read this part. To me that sounds like one of the finish leads is touching the baseplate. Does the pickup have a cover on it?

It might just be a broken connection to a lead wire where the hot end of the cable is connected.

Some times people take the covers off and put them back on and brake things.

+1
The cover/baseplate are "hot". It has to be the finish wire pigtail touching inside, otherwise it wouldn't measure as open.