Problem Wiring An Old Dimarzio P Bass Style Pickup

[mkat]

Hi,

I have an old Dimarzio P bass style pickup in one of my basses, that I haven't used for years. I tried to wire it, but I can't get it to work. Here are some details:

Top pickup (E & A strings)

------------------------------

green (tone pot)

white (joined to brown wire coming from bottom D & G pickup)

Bottom pickup (D & G strings)

----------------------------------

brown (joined to white wire coming from top E & A pickup)

yellow (volume)

Capaciter

-----------

0.05+

- 10%

N 100V

I tried P bass pickup (not the active one) diagram at the Dimarzio web site but it didn't work.

Does anyone know how I can wire this thing?

Regards,

Michael

[lovekraft]

Try wiring the green wire to ground and the yellow wire to the hot side, and tape off the other two wires so they don't accidentally short against anything - that should do it. I'd temporarily straight-wire it directly to the jack, so any mistakes you made in the pot wiring won't affect it. If you get sound, then go back and debug the pot wiring - if you don't, check the pickup coils for continuity.

[mkat]

I'm not up with the jargon, what do you mean by "hot side"?

[mkat]

Sorry, I missed another wire. Here are the actual wires...

Top pickup (E & A strings)

------------------------------

light green (tone pot)

white (joined to brown wire coming from bottom D & G pickup)

Bottom pickup (D & G strings)

----------------------------------

dark green

brown (joined to white wire coming from top E & A pickup)

yellow (volume)

Capaciter

-----------

0.05+

- 10%

N 100V

Any suggestions about the dark green wire on the bottom pickup (see above).

Regards,

Michael

[lovekraft]

Yeah, wire the other green to ground also. "Hot side" simply refers to the signal path (not ground, so "hot"). It'll be the tip conductor on your jack.

[mkat]

OK, thanks for that. I've tried it, but it still doesn't work. So, I've unsoldered and seperately checked the pots, the pickups, the capacitor and they all emit a signal. The pots are ~507 & 488 (both 500k). I'll post the resistance of the capacitor and pickups tonight.

Any other suggestions, before I send more info?

Regards,

Michael

[lovekraft]

Yes, we definitely need readings from the pickups.

[mkat]

ok...

pickups: ~5.62

pots: ~507, ~488

capacitor: 0.05+-10%

I've rewired them as outlined above and still no sound. When I touch the metal volume and tone nobs there is a loud hum.

I tried using 250k pots and a slightly different capacitor, but same deal.

Regards,

Michael

[lovekraft]

OK, shame on me for not making myself clear - i need to know what the resistance is from each wire on each coil to each other wire on that same coil.

It sounds like you either have your ground reversed or no ground at all. Can you describe exactly how you have everything wired, from pickup coils to output jack?

[mkat]

Ok, some slight changes but here is the messy info

Top pickup (E & A strings) - resistance 5.76K

------------------------------

light green: wired to volume pot (ground)

white: soldered to brown wire coming from bottom D & G pickup

Bottom pickup (D & G strings) - resistance 5.73K

----------------------------------

brown: soldered to white wire coming from top E & A pickup

yellow: wired to volume pot (left lug, where lugs are pointing down and bottom of pot is facing up)

- yellow wire from left lug on volume pot to middle lug on tone pot

- black wire from middle lug on volume pot to the jack tip

- black wire from right lug of volume pot to volume pot (ground)

- yellow wire from bridge to jack sleeve

- Capaciter (473j, 2A0SG): soldered to left lug (where tone lugs are pointing up and bottom of pot is facing up) on tone pot and bottom of tone pot (ground)

Note: There is a dark green wire wired to the jack sleeve. This connected to a plate under the pickups, which is not connected to the pickups.

Here is a pic of it, just so it makes more sense

http://users.bigpond.com/m.kat/html/fretless/pbwiring.jpg

Edited February 26, 2005 by mkat

[lovekraft]

OK, now that you've got a picture of how it's wired, disconnect the pickup coils from everything (including one another) and get us some valid readings from each coil wire to each other coil wire. Accurately measuring resistance in circuit is impossible. Don't worry about anything else for now, just measure the pickups.

[mkat]

I didn't mention it, but that's what I did (as indicated in the resistance measurements in my last post). I actually unsoldered everything prior to taking the measurements and the pic. Then I took the readings, when all pickup wires were not connected to anything (same deal for the pots, all clean no wires or capacitor). Once I had the readings, I soldered the wires back together for the pic. I get soldering practise this way, as you can see I need it.

Hope that's what you meant. I worked out a few days ago, when I bought the multimeter, that I couldn't get accurate readings with everything wired.

Regards,

Michael

Edited February 26, 2005 by mkat

[lovekraft]

OK, disconnect everything but the pickup, and wire it directly to the output jack, yellow to the tip lug and green to the sleeve - if at this point you get no sound, it's time to replace the pickup.

[mkat]

Fantastic, I have sound. What next?

[lovekraft]

Now we slowly add parts back in until it stops - then we know what to replace! OK, remove the yellow wire from the jack and hook it back up to the bare volume control (leave the tone pot disconnected for now). Run a jumper wire from the jack's ground lug to the volume pot ground, and jumper the pot's wiper (center) lug back to the jack's tip lug. The volume pot should work now - if it doesn't, there's either a bad connection or a bad pot.

Edited February 26, 2005 by lovekraft

[mkat]

I've done that. I still have sound, but the volume does not work (stays the same when turned all the way up or down).

I've had a big day today, so I'm gonna crash. I'll continue again tomorrow.

Regards,

Michael

[lovekraft]

Sorry, I forget you guys in Oz are about 15 hours ahead of me! When you get up, check the ground on the volume pot - it sounds like there's no ground connection to that lug. If that fixes it, hook up the tone pot and wail away!!

[mkat]

Ok, I sorted out the problem with the volume pot, it now works. So, should I wire the tone pot the way I had it wired before (in the pic)?

Also, the green wire is still connected to the jack sleeve, is this ok?

Got to do a few things and will log on again tonight.

Regards,

Michael

[lovekraft]

Yes, you should be able to reconnect the tone pot and move the green wire back to its original spot without any problems now - holler if it acts up again, but I think you've corrected the problem.

[mkat]

I've reconnected the light green wire to the back of the volume pot (ground) and have connected the tone pot. The volume pot works, but the tone pot does not work. I've connected the tone pot the same as the pic I posted. Any suggestions to correct the tone pot wiring?

Note: The current wiring is slightly different to the original. Might send another pic to make things easier.

Regards,

Michael

[lovekraft]

Try connecting the tone pot ground lug to the volume pot's ground - that should take care of it.

[mkat]

Both pots now work, I didn't have to connect the tone pot ground lug to the volume pot ground. However, there is some hum or buzz, which stops when I touch the volume or tone pot. How can I get rid of that?

Here is another image with how it is now wired:

Regards,

Michael

[lovekraft]

It might help to connect the bridge ground lead to the back of the volume pot with the rest of the ground leads, and shielding the cavities might also help - see Guitar Nuts for more info.

[mkat]

Thanks for all your help. I started with nothing working and some wasted time, to everything working and creating some music. Thanks for all your assistance, patience and logical thinking, which has enabled me to learn a thing or two.

Regards,

Michael