Hum from BMI Guitar with an Original BL705

Ken Mizell · Post by **Ken Mizell** » 15 Dec 2020 3:14 pm

I just bought a used, refurbished, BMI SD-10 (3/4 body). It's in very nice shape, in all regards. It has an original Bill Lawrence 705 in it - the original with the chrome around it. There are no signs of damage.

The pickup works, however, when I get my hands near the pickup, it starts to hum, and is rather annoying. It's even worse when I actually touch the chrome surrounding the pickup. The volume of the hum varies with the volume pedal position. When experimenting, I eliminated the volume pedal, plugging directly into the amp, and I've also tried more than one cable between the guitar and the amp. Everything I try gives me the same noise.

I haven't messed with the pickup or the jack on the guitar yet.

I'm hoping there is nothing wrong with the pickup, since this is an original BL705, and any replacement isn't cheap. If it's a problem with the wiring at the jack, that will be easy.

Any ideas or guidance will be most appreciated.

Mike Auman · Post by **Mike Auman** » 15 Dec 2020 3:58 pm

Ken, it sounds like there's a wire disconnected, probably a ground. If so, it would be either black insulated, or plain stranded wire with no insulation. Trace those from the pickup to the output jack and look for a loose end.

Ken Mizell · Post by **Ken Mizell** » 15 Dec 2020 4:59 pm

Thanks Mike. I'll turn the guitar over and start looking. It's open territory in the area of the pickup wires and jack.

Ken Mizell · Post by **Ken Mizell** » 15 Dec 2020 5:14 pm

Here's what I found. I think I need to get my soldering iron out and heat it up. The top one doesn't look too good, but the bottom one certainly needs some work.

Mike Auman · Post by **Mike Auman** » 15 Dec 2020 5:58 pm

Yep, I think that black wire is the culprit.

Ken Mizell · Post by **Ken Mizell** » 15 Dec 2020 6:22 pm

I'll report back on the outcome.

Ron Pruter · Post by **Ron Pruter** » 17 Dec 2020 7:57 pm

Check to see if there is a wrap around shield around the blk and red wire back at the first see-through strap/screw connector. If there is, connect that wrap to the same connection as the black wire on the jack. If this doesn't help after you've done all the work previously mentioned, Measure the ohms of the pick up with an ohm meter and let us know. Should be somewhere between 12k-20k ohms. Very high or very low readings spells trouble. RP

Ken Mizell · Post by **Ken Mizell** » 22 Dec 2020 6:03 am

Update: I put in a new jack. Red to tip. Black to ground. I pealed off the black electrical tape and I find no shield. I did, however, find a green and white wire soldered together. Per info I found on another thread, connecting the white and green wires turns ON the single coil. Disconnecting the white and green turns ON the humbucker. So, the pup should be wired correctly now. The hum and sensitivity to touch is better, and may have decreased 75-80%. It is still noticeable enough to be annoying, kind of like a single coil pup in a bad electrical environment. Solution. - New pickup. A friend of mine has several spare, barely used pickups (almost a shoe box full), and he gave me a few to try. He will sell me what I want. Iâ€™m going to decide between a George L E66, and a BL 710 or LxR-16 (labeling is messed up, not sure what it is). I donâ€™t have an ohm meter, yet.

Ken Mizell · Post by **Ken Mizell** » 22 Dec 2020 6:27 am

I found this diagram on the Bill Lawrence pickups web site. I may have the pickup wired wrong. Thoughts?

Calvin Todd · Post by **Calvin Todd** » 26 Dec 2020 3:20 pm

Just got a Carter with Xr16â€™s and love em! Make sure you give those a good shot

Ken Mizell · Post by **Ken Mizell** » 31 Dec 2020 5:57 pm

I solved my problem today, with this:

The tone sounds really good to me. The pickup is extremely quiet and clear. I'm liking this pickup a lot. The E66 is staying in the BMI.