I Think My JB is Broken, anybody good with wiring?

[Frazer Stockton]

The strangest thing has happened to my strat. It was working perfectly fine until my most recent string change. As soon as i had relatively tuned the fresh set, i proceeded to plug it into my tuner for fine touches, and i noticed the tuner picked nothing up. I immediately tried a different cable but still nothing came up. I plugged another guitar into the tuner, and it works fine. Hmmmmm!

At this point I had come to the conclusion, "oh great, probably the darn input jack's come loose" but upon taking off the cover, it looks perfectly fine, and makes good contact with the cable, i tested this with a multimeter to see if i could get a current through. worked fine.

Out of curiosity i plugged my guitar into my amp, now this is the strange part. On a clean channel, i hear nothing, not a sound. On a distorted channel i get the very VERY VERY!! faintest sound coming out my amp of my guitar. (it has to be pretty well cranked)

By now im very confused, and worried. I took the strings back off, and unscrewed the scratchplate to have a look inside, from what i can see nothing is wrong. I couldn't even tell you if the guitar tech made a good job installing the pick up, my knowledge of wiring is relatively limited.

I best explain how my guitar is wired. I have a JBSH-4 running through a 500k volume pot, then straight to the output jack. (About a year ago i added the JB.) The other pots and 5 way switch do absolutely nothing and from what i can see, nothing is wrong.

I would really appreciate it, if someone who knows how these things work, could take a look at the pictures below. It really has me stumped, and if the guitar tech in my town has made a bad job, id be reluctant to take it back for repairs.


Kind Regards
Frazer


(In the second picture i put a line through everything not used. I checked the wire that runs through to the springs was connected, and that looks fine.)

 

[ehdwuld]

Re: I Think My JB is Broken, anybody good with wiring?

check your guitar cable

if you have a Multimeter

check between the black and green connections
( looking for continuity )

if you have a bad solder connection at any of these points the circuit will not function
A: the black wire on the volume pot
B: the red/white connection of the pickup
C: the green wire connection to the ground
D: the ground connection to the Jack
E: the ground connection on either end of the cable
F: the hot connection on either end of the cable
G: the hot connection on the Jack
H: the hot connection from jack to volume pot

 

[Ed Hunter]

Re: I Think My JB is Broken, anybody good with wiring?

On the duncan there are 5 wires, a red,green,black,white and a bare but in the pix u posted i dont see the bare wire with the green wire
soldered to top of the pot like it should be?

 

[Frazer Stockton]

Re: I Think My JB is Broken, anybody good with wiring?

The bare wire is there, its soldered very close to the end of the black cable cover, practically underneath.

 

[Frazer Stockton]

Re: I Think My JB is Broken, anybody good with wiring?

I will check with the multimeter tomorrow and let you know how it goes, thanks very much for the prompt replies!

 

[Ed Hunter]

Re: I Think My JB is Broken, anybody good with wiring?

The bare wire is there, its soldered very close to the end of the black cable cover, practically underneath.

i knew that would be too easy! Lol
all u did was change strhngs? One time i had a similar prob that turned out to be the input lug of the pot, the solder connection was fine but the lugs connection to the pot itself was loose ?

 

[Frazer Stockton]

Re: I Think My JB is Broken, anybody good with wiring?

Well Ed, now you mention it ... while it still had the old strings, i put the whammy bar in for a giggle and played about a little (I never use one) ... but to be honest, even though my bridge is quite tight and flat against the body, it shouldn't effect the pickup at all.

That's the only thing I've done differently.

What puzzles me is, how anything can become loose or broken inside the guitar. The only moving parts being the input jack and volume pot. Even if a wire does have a bad connection, the guitar has worked perfectly fine for over a year. Is there anyway i could have damaged the pickup? perhaps left another magnet near it or, anything like that? (not that i can recall doing that)

EDIT: I mentioned earlier, i hear my guitar very very faintly when i have it plugged into my distorted amp. Does this man theres a faulty connection? Or could it possibly suggest anything?

 

[Ed Hunter]

Re: I Think My JB is Broken, anybody good with wiring?

I honestly dont think the jb is the prob. One thing u can try is touching the center output lug of the pot with the guitar plugged in , Ur amp doesnt have to be real loud, u are just checkin to see if there is a signal post input. If u get a signal by doin that then the prob is before the output of the pot and we can take it from there.

 

[Frazer Stockton]

Re: I Think My JB is Broken, anybody good with wiring?

Center output lug? Not quite following you here mate, it must be my "scottish-ness" and lack of technical terminology in my life Do you mean the output jack? Or one of the pole pieces or screws on the pickup? How would i go about touching it, just by hand to see if it crackles?

 

[Ed Hunter]

Re: I Think My JB is Broken, anybody good with wiring?

Center output lug? Not quite following you here mate, it must be my "scottish-ness" and lack of technical terminology in my life Do you mean the output jack? Or one of the pole pieces or screws on the pickup? How would i go about touching it, just by hand to see if it crackles?

on the volume pot there are 3 lugs one is where the jb's black wire is soldered to and the middle one is the output of the pot. Just use ur finger tip or a screwdriver to touch it to hear IF u get a signal?

 

[Frazer Stockton]

Re: I Think My JB is Broken, anybody good with wiring?

I will have to get back to you on that tomorrow as its half 1 in the morning. Thank you for the help! It's much appreciated.

 

[ehdwuld]

Re: I Think My JB is Broken, anybody good with wiring?

yea I'm thinkin it probably would be the pot too

where the wire from the jack comes up to the volume pot
make a jumper to where the pickup's black wire is
( bypassing the pot ) lets see if that gets sound
if so then jsut replace the pot

 

[Ed Hunter]

Re: I Think My JB is Broken, anybody good with wiring?

yea I'm thinkin it probably would be the pot too where the wire from the jack comes up to the volume pot
make a jumper to where the pickup's black wire is
( bypassing the pot ) lets see if that gets sound
if so then jsut replace the pot

agree and this will narrow things down. A duncan rarely just goes dead.

 

[GuitarDoc]

Re: I Think My JB is Broken, anybody good with wiring?

It's gotta be the potta.

 

[AudioWonderland]

Re: I Think My JB is Broken, anybody good with wiring?

agree and this will narrow things down. A duncan rarely just goes dead.

Its rare but it does happen. I had a 59 go rogue like this on me. I would certainly unsolder the pickup and test the pickup and the circuit/components

 

[Frazer Stockton]

Re: I Think My JB is Broken, anybody good with wiring?

Well, shock horror, my soldering iron seems to have gone walkies. This has not been my week at all!

However I used my initiative with the multimeter.

Leaving everything still soldered onto the pot and the way it was.
I tested the bare wire (from the pickup) and the black wire on the lug of the pot. Am i right in suggesting this should make a beep?

Also ehwuld, I took your advice and tested the jack and black wire, and nothing at all happened. Would this clarify, it actually is the pot which is causing me all this trouble?

Again many thanks for the help, you guys are probably saving me from a HUGE technician's bill.

 

[ehdwuld]

Re: I Think My JB is Broken, anybody good with wiring?

check with the meter the black to green
meter set to ohms
the JB should read 16K ohms or some such
if you have continuity thru the pickup then

on to the pot
one lead where the jack comes in to the volume pot
and one to the ground
roll pot all the way in one direction then all the way in the other
should be the 16K in full ON and 0.1 in the OFF position
what this translates to
is ON is the pickup
OFF is shorted to ground

looks right?
next plug a guitar cable into the jack
one lead on the tip of the exposed jack
one lead on the "sleave" ( thats the area just below the black ring on the jack)
roll pot again
16K and 0.1
good?

if not then either jack or cable test cable first then jack

if at any point your readings are not consistent with what has been given then
report back your findings as they may shed more light on your problem