P94 tone pots giving trouble

[m165]

Just wondering if anyone is using the gibson P94 pu and what value pots and caps are suitable, both my tone controls , Gibson support reccomended using 300k Linear taper for the volume and 500k Audio taper for the tone with.022 capacitor, I guess they should know but want to see if any users on here can clarify this a little bit more.  Thanks.

 

[blue313]

What problems are you having with them?

 

[m165]

The guitar had been out of action for a couple of months, and both tones controls  now seem to have died, or work now and again, have checked the soldering etc, appears to ok, so might try to replace them both.

 

[disaster]

I don't know how old the pots are but they may just need cleaned.  The pot contacts corrode over time.  If you can find electrical/electronic contact cleaner locally give it a try.  (The only place I can think of is Radio Shack or Ace Hardware - maybe.)  You'll have to gain access to the pots (either remove backplate covers or pickguard).  Then spray the pots as best you can, inside & out.  The trick here is to prevent the cleaner from saturating the finish of the guitar.  I'm not sure how the 2 will react.  If you can rest the guitar over the end of a work table w/ the pots pointed towards the floor you should be able to spray into them and have the excess drip down on the floor (don't do this over carpet or tile or anything but a floor that you don't mind discoloring).  The other option is to remove the pots from the guitar & clean them in a bucket, then re-install.

Good Luck.

 

[m165]

Thanks for the tips, but I have already removed the pots to replace them, as per Gibson adviice with 300k linear for volume and 500k audio for tone, tone pots now working but I seem to created another problem, I am getting bad noise when either pu is used on its own but disapears when both are on with switch in middle position  :icon_scratch:

 

[blue313]

Knee jerk response would be to check your grounds. But, what kind of noise is it making?

 

[m165]

It does sound like a ground hum but have checked all the wiring, but would a ground hum disappear when using both pickups, if it was due to a faulty ground connection?. 

 

[Funky Phil]

Reverse wound/reverse polarity?

This would cause the hum to go away with both pickups on...

 

[disaster]

To check for a faulty ground connection try attaching a ground directly from your bridge to your AC ground (I made a little cable for this for my guitars - its great for troubleshooting noise problems).  If you have a ground problem this should eliminate the "hum".  If it doesn't you probably don't have a ground problem (you may also have an open between the pickup grounds & the bridge.  In this case you may have to connect the ground to various metal points on the guitar to see if the hum is reduced.  Try the input jack plate & the metal shaft on the pu selector switch).  If you can't make a ground wire you'll have to generate a detailed diagram of your connections in each switch position & see if you can find what would cause the "both on" position to impact the grounds.

IF YOU AREN'T COMFORTABLE MAKING CONNECTIONS TO AC WIRING DON'T TRY THIS AT HOME.  IT CAN BE EXTREMEMLY DANGEROUS.

Good Luck.

 

[neuftone]

Reverse wound/reverse polarity?

This would cause the hum to go away with both pickups on...

True...my first thought was that the P-94 is a single coil...my P-90s stop humming when combined.