No Tone function after adding passive P

[ack]

Hello all,
I have an old Peavey Unity Series PJ and I switched out the stock passive Split Coil Precision pickup to a DiMarzio DP-122 (to match the DP-123 already in the bridge position).
After I connected everything up, both pickups work fine, but I have no Tone control whatsoever.

Here are the only changes I made:
1. de-solder the old pickup ground from the back of V1 Pot
2. de-solder the old pickup hot wire from the middle lug of V1 Pot.
3. soldered the new Green to the back of V1
4. soldered the new Red to the middle lug of V1 (contact with capacitor)
5. Per DiMarzio's instructions the Black and White pickup wires get soldered and taped together

Thanks in advance for any advice - obviously I'm a complete novice at wiring. Sorry for the crude drawing.

Steve

 

[LoveThatBass]

Just off hand I would suspect you have either a bad capacitor on V3 Tone Pot or the pot is bad. Did you solder to the lugs of the tone pot by chance? If so you may have overheated it and damaged it. Do you have an ohm meter to "ring out" the circuit (pots and associated wiring)? If not that then next in line would be the wires connected to the tone pot.

 

[ack]

Just off hand I would suspect you have either a bad capacitor on V3 Tone Pot or the pot is bad. Did you solder to the lugs of the tone pot by chance? If so you may have overheated it and damaged it. Do you have an ohm meter to "ring out" the circuit (pots and associated wiring)? If not that then next in line would be the wires connected to the tone pot.

Thanks for the quick reply. I did not solder to the V3 Tone Pot at all.

I just put an Ohm meter to all of the pots:
- V1 and V2 (250k pots) both show 10.91 kOhms when I touch both of the outside lugs. Both have orange caps with "102" on them.
- V3 (Tone Pot - also 250k) shows 289 kOhms when I touch the outside lugs. The Cap has ".02Z Z5U" on it.

Should I be getting identical (or close) readings from all of the Pots?

In theory, I should be able to find a 250k Pot somewhere and get similar readings from the outside lugs (I think one lug is Power/Input and the other outside lug is Ground, correct?)

I've updated my cave painting to include some more info.

Thanks!
Steve

 

[LoveThatBass]

Thanks for the quick reply. I did not solder to the V3 Tone Pot at all.

I just put an Ohm meter to all of the pots:
- V1 and V2 (250k pots) both show 10.91 kOhms when I touch both of the outside lugs. Both have orange caps with "102" on them.
- V3 (Tone Pot - also 250k) shows 289 kOhms when I touch the outside lugs. The Cap has ".02Z Z5U" on it.

Should I be getting identical (or close) readings from all of the Pots?

In theory, I should be able to find a 250k Pot somewhere and get similar readings from the outside lugs (I think one lug is Power/Input and the other outside lug is Ground, correct?)

Thanks!
Steve

On volume pots #1 lug is ground

Thanks for the quick reply. I did not solder to the V3 Tone Pot at all.

I just put an Ohm meter to all of the pots:
- V1 and V2 (250k pots) both show 10.91 kOhms when I touch both of the outside lugs. Both have orange caps with "102" on them.
- V3 (Tone Pot - also 250k) shows 289 kOhms when I touch the outside lugs. The Cap has ".02Z Z5U" on it.

Should I be getting identical (or close) readings from all of the Pots?

In theory, I should be able to find a 250k Pot somewhere and get similar readings from the outside lugs (I think one lug is Power/Input and the other outside lug is Ground, correct?)

Thanks!
Steve

Volume pots lug 1 is connected to ground, #2 middle lug connects to pickup and #3 is signal out to output jack.
Make sure you read near zero ohms from tone pots case to ground on the output jack. If open or high reading that is your problem.
Pots will be a + or - 10% Of the stated value I.e. 225-about 275ohms. 289 a bit high but not that big a deal. On tone pot measure between the middle lug and the lug the cap is connected to and rotate the shaft all the way from one end to the other. You should get somewhere in the neighborhood of 250k when tone is at 10 and zero to 10 ohms with it turned down

 

[ack]

On volume pots #1 lug is ground

Volume pots lug 1 is connected to ground, #2 middle lug connects to pickup and #3 is signal out to output jack.
Make sure you read near zero ohms from tone pots case to ground on the output jack. If open or high reading that is your problem.
Pots will be a + or - 10% Of the stated value I.e. 225-about 275ohms. 289 a bit high but not that big a deal. On tone pot measure between the middle lug and the lug the cap is connected to and rotate the shaft all the way from one end to the other. You should get somewhere in the neighborhood of 250k when tone is at 10 and zero to 10 ohms with it turned down

OK!
It turns out that the .02Z Z5U capacitor on the Tone pot was bad or was on a cold solder joint. Once I replaced it with a 203, I got tone control back.

Can't thank you enough for all the help.

Steve

 

[LoveThatBass]

You’re welcome! Glad you got it fixed