Replacing Gibson PCB - with Poll

[smitty_p]

Alex,

I realize you have things working, now. But, I think I may see the problem with the hard-wired setup.

Unfortunately, I'm not in a situation where I can really get into it, right now. When I get some more time later to post with some pics, I'll point out what I see.

 

[Alex_SG]

OK cool. Thanks mate.

 

[smitty_p]

Okay, so here is what attracts my attention. Granted, it's mostly due the angle of the image and if I had a better look from different angles, there may not actually be any problem where I'm looking.

Anyway...

First, look at where I've circled in yellow. I can't see how well the grounds are attached. So, that is one thing.

Second, look at where I've circled in red. From the angle of the pic, it sort of looks like the green hot lead running to the output jack and the black ground are contacting each other. If this is the case, the signal is shorting out right there.



This is a quick pic I made of how the switch should be wired. Its very important that no signal wires touch the grounding lug.

 

[Huntroll]

Check the basics ...

1. Carefully remove circuit board assembly.

2. Inspect control cavity area for any conductive debris like bits of wire, metal shavings etc. that could be shorting out against the circuit board or pot internal workings.

3. With a small acid brush, sweep out the control cavity then hold guitar so any unseen lodged debris will fall out when you blow or vaccuum the area clean.

4. Now is the time to thoroughly inspect ALL the soldered connections on the circuit board.

Re-solder any questionable/poor connections.
As long as you have it apart, I would go ahead and re-solder the pots and jack.

5. Blow or vaccuum the pots clean. Conductive dust/debris may be lurking inside.

6. Carefully re-assemble paying attention not to create any problems like the ones found or checked for. Test operation.
　
Note: Keep in mind, Newer Gibson's that come with circuit boards do not have SHIELDED CONTROL CAVITIES.

You can confirm this with an ohm meter.

If removing the circuit board modifcation is to be done properly, you will have to add SHIELDING - (conductive paint or the metal (brass?) housing unit and the conductive silver foil to the cavity cover to prevent HUM that makes it sound like you have a bad cord.

 

[Daphne Gruntfuttock]

Personally I would have the live black wires from the PUPs soldered to the middle tags of the Vol pots and the green wires on the outer tags.

A treble bleed cap is a must as well, why Gibson don't fit 'em as stock is a mystery, must cost all of a few pennies to fit.

 

[JohnnyGoo]

Say Smitty thats the other thing i was lookin at but ya cant see good.couldnt tell by the pic if it was correct.is that a Strat selector switch ??? I think my Gibby one has one common post on the bottom for output to jack.not sure.anyway,

 

[smitty_p]

Say Smitty thats the other thing i was lookin at but ya cant see good.couldnt tell by the pic if it was correct.is that a Strat selector switch ??? I think my Gibby one has one common post on the bottom for output to jack.not sure.anyway,

No, it isn't a Strat switch. It looks like Alex is using the tried-and-true Switchcraft right-angle, 3-way switch (as I showed in my pic above). In most cases, the two output contacts are actually pinched together and the wire to the jack is looped through both contacts. Then, the wire and both contacts are soldered together. This accomplishes the same as jumpering them, and would essentially have the same result as a common output post.

 

[Biddlin]

Good luthier, keep him! (I still haven't attached the friggin wee Molex connectors w'out buggerin' the job. It is possible to solder leads from a replacement pickup to the pots on the PCB and in the case of my LPJ, that's what I ended up doing.)
I honestly don't know how many of mine have PCBs, but I haven't had need to swap any other parts, yet.
;>)/

 

[JohnnyGoo]

Ok ya thats the way mine is,ur right now that i think about it.pic kinda looked a little different.they are pinched together and soldered. Yep

 

[Alex_SG]

Second, look at where I've circled in red. From the angle of the pic, it sort of looks like the green hot lead running to the output jack and the black ground are contacting each other. If this is the case, the signal is shorting out right there.



This is a quick pic I made of how the switch should be wired. Its very important that no signal wires touch the grounding lug.

OK. The switch was one thing that I thought could be causing the problem... I did double and triple check the wires and solder joints to ensure they weren't touching each other. I think the angle of the photo makes it look like they are, but honestly, they weren't.

And yes it was a Switchcraft Right Angle 3 way switch, which was the original out of the SG in the first place. And yes, the output lugs were joined together so you only needed to solder one wire to them.

I'm thinking maybe the earth soldering was the culprit...

The luthier asked if I wanted the original pcb board back in, or if I definitely wanted it handwired. I told him I'd only removed the pcb because of a faulty pot, and for no other reason. Otherwise I would have left the harness I'd made in there and let him sort it out.
Now that it's all back together and working, I'm as happy as a clam!

I probably could have got the store I bought the SG from to fix it under warranty, but they send all their repair work to my luthier anyway, and he only charged me for the pot, and $20 for labor. All up was $30 and change...

(And I wouldn't have to drive 30 Km to the store to drop it off, wait 2 weeks for the store to send it to him, wait for the repair, then wait another 2 weeks for the store to collect it from him and then drive another 30 Km to the store after they had rang me and told me it is ready!)

My luthier works from a workshop behind his house, which is literally about 6 Km from my house! A lot easier to cut out the middle man... And it took less than an hour from the time he opened the rear cavity, tested the components, fixed the fault, replaced everything, tested it (played some awesome Led Zeppelin!) and closed the cavity up.

Thankyou all for your input... I really appreciate it! I may not be replacing the pcb again in this guitar, but the tips you have given me will definitely help next time I take on a rewire job!

 

[Kris Ford]

Glad it all worked out..but you would be a LOT more happy with the 500K pots, especially with the 490s.......

 

[Col Mustard]

and who'll be the first to write the song about the
"Hooker with the Hot Iron..."

That's got a cool ring to it. I used to play some shady dives
when I was a young buck, and I always felt that the band and the
hookers were sort of in the same business. i still do, but I have
more dignity now, so that makes it acceptable. And I have more
respect for the hookers than most. But I never paid one...