Conductive paint resistance

[chilidawg]

So, I've got a very noob question. Working on my friend's PRS SE that has a very noisy guitar signal.
Buzzer in continuity mode didn't beep, so I switched to resistance mode.
I do think this is really bad, because the conductive paint is connected to ground, but I could be wrong.
What do you think guys?

How can I remove the shielding?
At least not with some sort of a destructive method to remove it, and I don't want to do this.
Different story if the guitar is mine. I wouldn't put shielding at all in the first place, because none of my guitars have shielding, I just wired them properly, and they're super quiet.

 

[PermO]

If there's no wiring mistake causing this, I would shield the cavities with coppertape.

Result on my passive pickup bass went from humm to being dead quiet. (it also had the black conductive paint)

 

[chilidawg]

If there's no wiring mistake causing this, I would shield the cavities with coppertape.

Result on my passive pickup bass went from humm to being dead quiet. (it also had the black conductive paint)

No wiring mistake, except all of the cavities are painted with this high resistance conductive carbon/graphite paint.
Also noticed only the pots cavity and the switch cavity that are grounded, because the metal parts are in direct contact with the paint, but the pickup cavities are not grounded.

I don't have copper foil tape at hand, so I'm using aluminum foil duct tape. It doesn't have a conductive adhesive, so an extra step is needed to make the connection intact from one foil to another. So far so good, I get a continuity resistance of 6 ohm for the pots cavity. Will continue taping the rest of the cavities and making sure they all connect together as one.

I don't use shielding tape or conductive paint with the guitars that I own. I used braided shield that I took from taking apart a shielded audio cable (leftover from making my balanced XLR and TRS cables), to cover my signal cable in the pots cavity. I have toured everywhere else including overseas, and never had any unwanted noise problem.

 

[JohnRoberts]

I've probably shared this before but I advocate capacitor coupling exposed guitar metal parts. It is a potential risk hazard when a player touches an energized mic (from say a mis-wired outlet) and provides the ground return path for that electricity through his body. It doesn't take much capacitance to provide an effective shield while limiting fault current below hazardous levels.

JR

PS; I've told this story too many times but while I was employed by Peavey last century we were sued by the family of a guitar player electrocuted by a rouge mis-wired (RPBG) outlet when he held two guitars, one in each hand from (Peavey) amps plugged into two different outlets. The amp plugged into the stove outlet provided the deadly safety ground path for the energized guitar amp plugged into the rouge outlet (hot safety ground). UL sat with us in court and testified that our amps were correctly wired and safe. The court condemned the house until the wiring was repaired.

 

[k brown]

What's a 'rouge' outlet?

 

[JohnRoberts]

What's a 'rouge' outlet?

RPBG.... here is TMI od-1

The cheap 3 light testers do not detect RPBG, I designed a tester that would but abandoned it because I couldn't justify investing that much money to sell a tester that needs to retail for <$10. Life is short.

JR

 

[k brown]

No mention of 'rouge outlets' in that link.

Do you mean 'rogue'?

 

[JohnRoberts]

RPBG "reverse polarity bootleg ground".... my outlet tester lights up red (rouge?) for energized safety grounds (bad).

Of course I meant rogue, I didn't say that in the article either.

Maybe read the article if you are still confused.

JR

 

[Speedskater]

Failures in Outlet Testing Exposed
July 15, 2013
Why standard outlet testing methods fail to reveal reverse polarity bootleg ground miswiring situations
Mike Sokol
https://www.ecmweb.com/construction/article/20897728/failures-in-outlet-testing-exposed

 

[JohnRoberts]

Yup, Mike Sokol is the moderator of his own forum over at Pro Sound web.. pwr and grounding

JR