#1
Hi all!

I have an old Bradley LP (Matsumoku made), many of you have seen it. Recently it it picked up a hum, and it only stops when I touch the pickups or the jack cover, still hums when i touch the strings or tail piece. The only wiring changes have been a new toggle, that was done years ago, and has been worked fine.

I know it's a grounding issue. Keep in mind, the main "harness" is a PC board from the 70s, with the toggle, pups, and jack wired to it.

Any suggestions where to start?
--- Joe ---
77 Bradley LPC || 07 PRS CE22 || 11 PRS MC58 Artist || 95/02 Fender Strat || 99 Gibson LP DC Std Lite
06 Ovation Elite-T || 12 Martin GPCPA4
Boss GT100 || Peavey Stereo Chorus 400 || Peavey Bandit 75 || Roland JC77
#2
Same as usual, check the wiring. I've never seen it happen before, but I suppose a wire going to the pickups could have broken, unusual though. Most of the time that is all inside and does not move around.

Could be though, you had a cold or weak solder joint and it finally gave up, have seen that happen. Before I learned to solder right it happened to every guitar cable I tried to do...

Anyway I would say open it up and take a close look at all wiring and every solder joint. If you can't visually find anything questionable in the solder joints, I'd go ahead and re solder everything in it. Only takes a few seconds each, no new solder usually required, just re melt the existing joints.

Use a pencil to flex the circuit board, and check everything on it. I found a broken contact going to a capacitor in my Fender Champ years ago that way, never could see it until I used a pencil to poke around on the board, then it made the cap move and I saw the break and fixed it. Bass control started working...Check connections on the PC board carefully, that's the most likely place for a bad connection.
Hmmm...I wonder what this button does...
#3
reflow the joints. also chopsticks are better than pencils .
WTLT 2014 GG&A

Quote by andersondb7
alright "king of the guitar forum"


Quote by trashedlostfdup
nope i am "GOD of the guitar forum" i think that fits me better.


Quote by andersondb7
youre just being a jerk man.



****** NEW NEW NEW!
2017-07-07 2017-07-07 Update and a Chat On Noise Constraints *** NEW FRIDAY 7/7
2017-04-13 RUN AWAY from COMPUTERS!!! TCE? RANT ALERT!!!
2017-03-02 - Guitar Philosophy 1001- Be Prepared For the Situation (Thursday 2017-03-02)
2017-02-21 How to Hot-Rod the Hell of your Stratocaster for $50! (Tuesday 2017-2-21)
Resentments and Rambling from a Guitar Junkie
---> http://trashedengineering.blogspot.com/
#4
True but how many people have chopsticks sitting around?

I normally use a foot long plastic screwdriver designed to fine tune a TV with, and not get shocked. But almost nobody has one of those...so I usually stick with pencil. If it's an amp I usually recommend something else, wooden dowel or something, because of the possibility the pencil could conduct current through the graphite.
Hmmm...I wonder what this button does...
#5
Quote by Paleo Pete
True but how many people have chopsticks sitting around?

I normally use a foot long plastic screwdriver designed to fine tune a TV with, and not get shocked. But almost nobody has one of those...so I usually stick with pencil. If it's an amp I usually recommend something else, wooden dowel or something, because of the possibility the pencil could conduct current through the graphite.


if you eat take out chinese every once in a while, just throw another pair or two in the bag . the only reason i said that was because of the freak chance it could zap you through the graphite. i don't know if it could happen but i wouldn't risk it.

and truth be told, i probably don't have a wooden pencil in my house. i have pens and mechanical pencils though. thats why i have chopsticks.
WTLT 2014 GG&A

Quote by andersondb7
alright "king of the guitar forum"


Quote by trashedlostfdup
nope i am "GOD of the guitar forum" i think that fits me better.


Quote by andersondb7
youre just being a jerk man.



****** NEW NEW NEW!
2017-07-07 2017-07-07 Update and a Chat On Noise Constraints *** NEW FRIDAY 7/7
2017-04-13 RUN AWAY from COMPUTERS!!! TCE? RANT ALERT!!!
2017-03-02 - Guitar Philosophy 1001- Be Prepared For the Situation (Thursday 2017-03-02)
2017-02-21 How to Hot-Rod the Hell of your Stratocaster for $50! (Tuesday 2017-2-21)
Resentments and Rambling from a Guitar Junkie
---> http://trashedengineering.blogspot.com/
#6
I've heard (on an amp repair forum) there is a chance of conductivity through the graphite, and it seems to make sense, so I usually don't take chances on it when working on my amps. Bad idea, tube amps carry up to 500VDC...literally deadly...

But the circuit in a guitar shouldn't pose any problems.

Yeah I need to grab some chopsticks next time I go to a Chinese buffet. I have a pair stored in a box, don't know where they are though. I usually use my TV screwdriver, it's plastic, over a foot long and works great.

OK sorry, didn't mean to derail the thread...
Hmmm...I wonder what this button does...
#7
Well I looked it over... I'll damned if I can find the issue. The hum drops some when I touch the output jack, completely when I touch the strings and jack.

Could a pot going bad be the culprit?
--- Joe ---
77 Bradley LPC || 07 PRS CE22 || 11 PRS MC58 Artist || 95/02 Fender Strat || 99 Gibson LP DC Std Lite
06 Ovation Elite-T || 12 Martin GPCPA4
Boss GT100 || Peavey Stereo Chorus 400 || Peavey Bandit 75 || Roland JC77
Last edited by Auriemma at Mar 23, 2015,
#8
Quote by Auriemma
Well I looked it over... I'll damned if I can find the issue. The hum drops some when I touch the output jack, completely when I touch the strings and jack.

Could a pot going bad be the culprit?


maybe you have a bad ground to the pot.

i can't think atm.

hit it with a meter, see where everything goes.
WTLT 2014 GG&A

Quote by andersondb7
alright "king of the guitar forum"


Quote by trashedlostfdup
nope i am "GOD of the guitar forum" i think that fits me better.


Quote by andersondb7
youre just being a jerk man.



****** NEW NEW NEW!
2017-07-07 2017-07-07 Update and a Chat On Noise Constraints *** NEW FRIDAY 7/7
2017-04-13 RUN AWAY from COMPUTERS!!! TCE? RANT ALERT!!!
2017-03-02 - Guitar Philosophy 1001- Be Prepared For the Situation (Thursday 2017-03-02)
2017-02-21 How to Hot-Rod the Hell of your Stratocaster for $50! (Tuesday 2017-2-21)
Resentments and Rambling from a Guitar Junkie
---> http://trashedengineering.blogspot.com/