#1
I recently picked up a Yamaha Pacifica(used)
I have noticed a VERY annoying hum when plugged into an amp.

I have tracked the following down:
When the volume is turned all the way up the hum goes away
When the volume is touched(without the knob, just the actual knob) the hum goes away
when the jack plate is touched, the hum goes away

When the volume AND jack plate are touched, the hum comes back

Any ideas what to look at for a problem?
#3
check that the ground wire to the bridge, located in the back trem cavity is attacted to the metal bar in there.


then make sure your guitar cable is good.

to check any other ground wires in the guitar, besides the output jack wires. you'll have to take off the pick guard.
Jenneh

Quote by TNfootballfan62
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#4
yeah grounding. kind of odd that it goes away when the volume is all the way up though. maybe a bad potentiometer if not just a ground problem or maybe a combination of the two.
#5
Quote by lp_std
grounding.


This.
Take it to a shop if you're not comfortable with poking around inside your guitar.
#6
taking off the back plate is just 6 screws. there's no other electronics in there except for the ground wire.

if it's not attached, that's your problem.
Jenneh

Quote by TNfootballfan62
Jenny needs to sow her wild oats with random Gibsons and Taylors she picks up in bars before she settles down with a PRS.


Set up Questions? ...Q & A Thread

Recognised by the Official EG/GG&A/GB&C WTLT Lists 2011
#8
the ground wire is attached. Everything seems ok. but the umming is still there. I have taken off the pick guard to try to trace it down, redone the solder point on the jack itself...still nothing
#9
Does the humming decrease if you switch the selector to bridge position?
It could be 60 cycle hum on the neck or mid pickups?
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#10
you could probably use a voltage meter to try to isolate exactly where the grounding problem is. Of course if you don't have access to one of these you'll probably have to take it to the shop since you're not able to see what the problem is exactly.
#11
I have access to a voltage meter. What should I be reading and where?
#12
Quote by Stratoblaster73
Does the humming decrease if you switch the selector to bridge position?
It could be 60 cycle hum on the neck or mid pickups?

no change in sound when changing the selector switch
#13
it's definately a grounding problem. you can look into star grounding.

and quiet the guitar even more by shielding the cavity and gaurd and then additionally grounding the guard.

i would suggest looking at the grounding at that noisy pot, but you said you went all over that.
Jenneh

Quote by TNfootballfan62
Jenny needs to sow her wild oats with random Gibsons and Taylors she picks up in bars before she settles down with a PRS.


Set up Questions? ...Q & A Thread

Recognised by the Official EG/GG&A/GB&C WTLT Lists 2011
#14
Quote by jj1565
it's definately a grounding problem. you can look into star grounding.

and quiet the guitar even more by shielding the cavity and gaurd and then additionally grounding the guard.

i would suggest looking at the grounding at that noisy pot, but you said you went all over that.


I didn't test the pot(don't know how). I did actually shield the cavity and guard, when I was resolding the jack etc.

Do i need to remove the pick guard again? it sucks cuz that means i'll have to restring the entire, which means removing all teh strings, and the issues associated with that
#15
http://www.guitarnuts.com/technical/electrical/trouble/strat.php

i found the page i was looking for, has the jack at the bottom using a meter. to test.


did you put the black ground on the innermost jack lug?

that's really a long shot, but maybe you mixed them up.


anyway, yeah you're probably going to have to open it again. or attach a metal clip to the bridge saddle and run a wire to your waist band and tuck it in there to ground while you play.
no im not kidding.

that'll quiet it until you feel like changing strings and taking it all apart again.
Jenneh

Quote by TNfootballfan62
Jenny needs to sow her wild oats with random Gibsons and Taylors she picks up in bars before she settles down with a PRS.


Set up Questions? ...Q & A Thread

Recognised by the Official EG/GG&A/GB&C WTLT Lists 2011