Strange pot problem...

Basshoofd · #1 07-01-2009, 09:35 AM

So I worked on my first bass mod. I installed Dimarzio Model J's in my Squier VM Jazz, and I switched to CTS pots with a Gotoh bridge.

The problem: Only positions 9 and 10 work on my volume pots. It seems as if all positions from 0-8 are silent, then when I turn it up a bit more suddenly the sound 'pops' on (although the output is pretty low). I not really sure if the tone control works properly.

I wired the pots and pickups correctly as far as I can tell. I took the capacitator of my old 500k tone pot and put it on my new 250k tone pot, was this the right thing to do?

Do you think I damaged the pots from the soldering? Or did something else go wrong? If necessary, I'll make a diagram of how everything is wired now. Thanks for your time

OriginalKeyster · #2 07-01-2009, 09:54 AM

Oops, thought you meant something else. Never mind.

Suhr · #3 07-01-2009, 03:30 PM

Quote:

Originally Posted by Basshoofd

So I worked on my first bass mod. I installed Dimarzio Model J's in my Squier VM Jazz, and I switched to CTS pots with a Gotoh bridge.

The problem: Only positions 9 and 10 work on my volume pots. It seems as if all positions from 0-8 are silent, then when I turn it up a bit more suddenly the sound 'pops' on (although the output is pretty low). I not really sure if the tone control works properly.

I wired the pots and pickups correctly as far as I can tell. I took the capacitator of my old 500k tone pot and put it on my new 250k tone pot, was this the right thing to do?

Do you think I damaged the pots from the soldering? Or did something else go wrong? If necessary, I'll make a diagram of how everything is wired now. Thanks for your time

You probably shorted out the capacitor or something simple
Post a picture, if you are not proud of the wiring then maybe a good tech should look at it

MatticusMania · #4 07-01-2009, 03:36 PM

I usually call up a friend when I have a problem with strange pot.

gonzorob · #5 07-01-2009, 03:49 PM

Quote:

Originally Posted by MatticusMania

I usually call up a friend when I have a problem with strange pot.

bongomania · #6 07-01-2009, 04:25 PM

There's like this sticky green resin all over it... will that mess up my "control cavity"?

MatticusMania · #7 07-01-2009, 04:30 PM

It won't do much permanent damage but the temporary effects of the resin can leave your tone slightly static.

RickenBoogie · #8 07-01-2009, 06:10 PM

It leads to stronger stuff, or so I've been told.

Elmo Oxygen · #9 07-01-2009, 06:19 PM

Never buy strange pot.

Wow, I guess this is how we get a West Coast roll call, huh?

danomite64 · #10 07-01-2009, 06:25 PM

Quote:

Originally Posted by Basshoofd

If necessary, I'll make a diagram of how everything is wired now. Thanks for your time

Post a pic of the wiring. A diagram will only tell me how you think you wired it......plus, the potheads will totally freak out over the groovy pic

walterw · #11 07-01-2009, 08:09 PM

did you somehow short the middle lugs of the pots to ground?

Basshoofd · #12 07-02-2009, 11:28 AM

Here's the wiring. I think everything can be seen.

CLICK HERE

Red wires = Hot from pickups to respective middle lugs, the smaller reds are left lug(neck)->left lug(bridge)->middle lug(tone)
Green wires = Ground from pickups to backs of respective pots.
Yellow wires = Ground
Black wire = Ground to bridge

The volume pots have their right lugs soldered to itself for grounding.

The tone pot has a Squier VM Jazz capacitor from the right lug to its back.

Internally, both pickups have the black and white wires wired together as suggested by the Dimarzio manual for series wiring.

Another shot HERE

Thanks everyone!

p.s. Way to make fun of my english

Basshoofd · #13 07-03-2009, 06:41 AM

Edited with link instead of direct image

bongomania · #14 07-03-2009, 09:49 AM

Quote:

Originally Posted by Basshoofd

Way to make fun of my english

Oh, we weren't making fun of your English at all, it just happened to be an easy play on a word with double meaning.

paul_s · #15 07-03-2009, 11:28 PM

I can't spot a problem with the wiring per say, but you should really, really consider cleaning that wiring up. That's a rats nest.

walterw · #16 07-04-2009, 01:15 AM

is it that the pickups are just real quiet until the pots are up to 8 or 9? if so, linear volumes will give you a much more even sweep from 0 to 10.

Basshoofd · #17 07-04-2009, 01:20 AM

Quote:

Originally Posted by walterw

is it that the pickups are just real quiet until the pots are up to 8 or 9? if so, linear volumes will give you a much more even sweep from 0 to 10.

I believe they're completely "off" until they get to the highest positions where the sound pops on.

The overall output is pretty low with all knobs turned up, I tested it with my Micro Qtron and I couldn't get a single wah sound (just some synthy sound that you get when you play really soft)

BigDaveyTwinkle · #18 07-04-2009, 08:48 AM

Hello - Just upgraded to CTS linear pots on my Warmoth, running DiM Model J's as well. It's da shiznit, fo' sho.

Your tone pot is troubling me (the wiring is non-typical as well, IMO). I am not understanding why you have a red wire coming off the middle lug of the tone pot going to the middle lug of your bridge volume pot? Is that part of your ground loop?

I have wired a few jazz basses (and had them work!) My suggestion would be to find a wiring diagram such as here:
http://www.axesrus.com/images/BASS1.jpg
and rewire exactly to that. It's like following a recipe when cooking. If you follow the directions, you probably won't go wrong.

Added:
With DiM Model Js, the green wires go to ground on the back of the volume pots, the red wires to middle lugs on volume pots, the neck black wire to bridge white wire, and bridge black to neck white.

blockinlay · #19 07-04-2009, 09:01 AM

Did you change your jack? If you have a cheap Chinese made jack, try changing it to a Switchcraft. The pots in an old Squire guitar I have were doing the same thing till I replaced the jack. Even fixed issues with the switch. Must have been something with the poor contacts. This was recommended by a luthier who runs a guitar shop and does dozens of guitar repairs weekly. He said that one thing alone is a major cause of many failures, and to do that first. I was ready to spend $40 on new pots and a switch, instead I already had a jack in my box and fixed it for nothing.

Well, I was just jamming it, and the switch is still acting up a bit at the bridge position until I give it a snap. The small squire Chinese made pots are functioning well through their full range. That didn't happen before the jack change.

walterw · #20 07-04-2009, 12:07 PM

Quote:

Originally Posted by Basshoofd

I believe they're completely "off" until they get to the highest positions where the sound pops on.

The overall output is pretty low with all knobs turned up, I tested it with my Micro Qtron and I couldn't get a single wah sound (just some synthy sound that you get when you play really soft)

my guess is that you're getting a partial short to ground somewhere in the chain, which is choking down overall output and making the pots act weird.

a stray wire"whisker" touching that black conductive shielding paint, a tab of one of the pots touching same, wire with the insulation partially melted against something else, something like that.

it's time to start pulling on and even redoing those wire connections.