color coding an unknown pickup

[sepultura999]

I can't seem to find ANY schematics on old teiscos, harmonys, kents, kingstons, etc. The kind where they would use 2 volumes, 1 tone, and 2 single coils with 2 slide switches (2 positions, 3 terminals, spst? I believe)

I saw the tutorial on projectguitar.com (http://projectguitar.com/tut/pickupwiring.htm) regarding pickup color coding for unknown pickups, tried it, and am having a problem figuring this out on these single coils. I have a black, a red and a green wire (which is a bit thicker than the red and black, but only one wire).

In regards to the tutorial, when I use my digital multimeter, the red and black wire come up with a reading of 0, so I am guessing these two don't go together. When I try the red and green, or the black and green, I get crazy readings. When I tap the single coil I may get a positive reading, but when I let go, I may get a positive reading or a negative reading, and the thing just keeps jumping between crazy intervals. And with the slightest movement of the pickguard, it jumps even more. What the heck is going on here?

Here is the schematic I made when I first opened up the guitar. I don't know if this was original wiring or not.

img167.imageshack.us/my.php?image=currentteiscowiring1rr9.jpg

As you can see it's a mess - the switches weren't working (I was assuming they were on/off, and if they were on/on you couldn't tell the difference in sound when being switched), and also there was a lot of buzz (which I will be shielding)

Any ideas, and help on how to get this guitar back to life? Even possibly a redrawn schematic? Thanks a lot.

[sepultura999]

*bump* anyone?

[sumgai]

sepultura999 said:

am having a problem figuring this out on these single coils. I have a black, a red and a green wire (which is a bit thicker than the red and black, but only one wire).

[W]hen I use my digital multimeter, the red and black wire come up with a reading of 0, so I am guessing these two don't go together.

Errrrr, not quite. A reading of 0 would indicate that the two wires are tied together - IOW, they are shorted. Whether or not that's proper remains to be seen.

When I try the red and green, or the black and green, I get crazy readings. When I tap the single coil I may get a positive reading, but when I let go, I may get a positive reading or a negative reading, and the thing just keeps jumping between crazy intervals. And with the slightest movement of the pickguard, it jumps even more. What the heck is going on here?

When you read a resistance from a component, it must not be 'live' - it can't have any voltages on it, AC or DC. But when you 'tap' the pickup, you are disturbing the magnetic field, which then cuts the coil, which then induces an AC voltage within the coil. While trying to read Ohms, that voltage is attempting to fry your meter. Fortunately for you, pickups can't put out quite enough voltage to kill a meter, but there's always a first time....... 'Nuff said, right?

Be sure that when you hold the meter test leads to the coil ends, you don't accidentally get your fingers in/on the circuit too. The meter will cheerfully accept any path through which it can measure, and your fingers will work just fine. The net result is that you get an incorrect reading - it jumps around, sometimes a lot.

Here is the schematic I made when I first opened up the guitar. I don't know if this was original wiring or not.

img167.imageshack.us/my.php?image=currentteiscowiring1rr9.jpg

As you can see it's a mess - the switches weren't working (I was assuming they were on/off, and if they were on/on you couldn't tell the difference in sound when being switched), and also there was a lot of buzz (which I will be shielding)

Any ideas, and help on how to get this guitar back to life? Even possibly a redrawn schematic? Thanks a lot.

Either that diagram is wrong, or you're mighty lucky that your guitar put out any sound at all!

You currently have two single-coil pickups. You have 6 tonal options in total:

1 - Neck
2 - Bridge
3 - Neck + Bridge
4 - Neck + Bridge, OoP
5 - Neck * Bridge
6 - Neck * Bridge, OoP

If you want more than the first three combos, you'll need to add more switches, either openly or clandestinely. What sounds would you like to have available for your listening pleasure?


sumgai

[sepultura999]

I just want it to have the first three. The switches to act like on/off switches. Nothing really fancy. Top switch to be for the neck pickup, and the bottom switch to be for the bridge.

I tested the wires for resistance. The black and red wires connected gave a reading of 2.5k or something along those lines. Replacing the black or red with green gave readings of 0.

I've heard of older pickups with three wires having "2 grounds". Perhaps that is what needs to happen. The only question is which one goes to the switch, and which two go to the center ground on the volume pot? If the red and black are to be tied together, then shouldn't they go to the center ground on the volume pot and the green go to the switch?

Anymore help would be most appreciative.

-Jamie

[ChrisK]

the red and black wire come up with a reading of 0

I tested the wires for resistance. The black and red wires connected gave a reading of 2.5k or something along those lines. Replacing the black or red with green gave readings of 0.

I believe that you are saying that black to red measured around 2.5K Ohms?

Are you also saying that black to green measured around 0 Ohms, and that red to green also measured around 0 Ohms?

Black to Red____Ohms
Black to Green_____Ohms
Red to Green_____Ohms

Also, when you measure the resistance of a pickup, you don't want any except one (preferably none) of the wires connected to anything.


The schematic doesn't make any sense to me. Can you take a few digital pics of the wiring and post the links to them?

[sepultura999]

The guitar has been disassembled (I probably should have mentioned that earlier.) The wires I'm testing from the pickup aren't connected to anything, which is how I hook them up to the multimeter. I could post a picture of the wiring before I disassembled it, however it's such a mess.

Don't get confused with yellow wires connecting to yellow wires. I can assure you that every wire is either connected to the base of a pot or a lug. I just did it like that because I wanted to make it clear through paint.

All I want to do is bring this guitar back to life. Keep everything original. This wiring job however wasn't original I believe. The person who gave it to me told me he had some guy rewire it. The switches didn't change the sound, or turn the pickups off, and the tone knob did nothing at all. This is what lead me to opening up the guitar.

I believe if I could figure out which wire is which, I could draw a new schematic. It is sort of similar to a les paul (correct me if I am wrong) - 2 3 lug switches (on/off), 2 vol, 1 tone, as opposed to 1 3 lug switch (on/on/on), 2 vol and 2 tone.

There could be a slight possibility (very rare I would say) that the switches I have are on/on (for what reason? I don't know. I guess for in phase and out of phase, or coil tapping or whatever) How could I test that the switches are on/off or on/on?

Thanks for all the help so far. Keep it coming

-Jamie

[sepultura999]

I took apart one of the pickups. Here's a picture

img155.imageshack.us/img155/7027/hpim1513zf6.jpg

Green is ground I am guessing. I can't tell out of the two if red or black is ground.

Like I said earlier, the pickup had an output of 2.5k. Also, the red and black would read 0k when hooked to the multimeter. I read that if the pickup's resistance is too low it could be short, and sumgai said they could be shorted as well. I am a noob when it comes to electronics - is the term "short" a bad one? What does it mean? The pickups are garbage and useless?

Thanks a lot.

-Jamie

[sumgai]

seppy,

Shorts are usually bad, but I did say 'the two wires appear to be shorted together', which meant only that they were connected together, probably by design. Otherwise, when we speak of a shorted pickup, we usually mean that it has gone bad.

2.5KΩ is pretty low. It's definitely not a short though, but it tells me that the pickup probably does not have much 'juice' - the output is anemic at best. Looking at your image, I can see why...... the coil is mounted on a magnet, which is then mounted on a spacer. That spacer is there to make the outer casing the same dimension as other pickups, so it will mount into the guitar with little or no problems. As you might have guessed, the spacer takes room away from how big the coil could have been, which translates to, the coil is undersized. And of course, we needn't repeat ourselves about what that means.

In your first post, you said that the black and red wires gave a reading of 0Ω, yet in a later post, you said they were 2.5KΩ - which is it? As we can see from your photo, the black and red carry the coil signal, so if they are shorted (0Ω), then you have a bad pickup. If the black and green read 0Ω, then that's probably supposed to be that way. But if the red and green also read 0Ω, then we have a real problem. Or did you perhaps mean to say, on one pickup the black/green combo is 0Ω, and on the other pickup, it's the red/green combo that reads 0Ω? That's possible, and might be significant in terms of hum reduction.

We need to know what the full story is before going any further here, including any potential wiring schemes.


sumgai

[sepultura999]

"Also, the red and black would read 0k when hooked to the multimeter."

Sorry, my fault. The red and black would read 2.5Ω, before when I was measuring in volts they would read 0.

Both pickups read 2.5Ω. The red and black wire are used on both pickups to get this reading. At a closer look, the green is soldered to a piece of metal (perhaps a magnet).

So, is it safe to guess that black is ground of the pickup, green is ground of the magnets, and red is the lead?

Also, is there a way to tell if the slider switches are on/on or on/off?

For potential wiring schemes, it's not going to be anything ridiculous. All I want is for how this guitar was intended to be (at least how I think it was intended to be). The neck and bridge pickup will have its own switch and volume, but share the same tone (why they did this is beyond me).

The reason why I took this guitar apart was because it wasn't sounding like how it should. The guitar looked like a bomb on the inside of it, which is why I dismantled it. Plus, I wanted to shield it. Though this guitar has 2.5Ω output, it doesn't sound too bad.

Does that help?

[sumgai]

seppy,

Yep, all that helps.

OK, your pickups may have a lower output signal, but as you correctly stated, it's how they sound that counts. If they sound good to you, then keep 'em - you can always turn up the volume on the amp, if needed.

Your two pickup switches are probably what you'd call 'on-on'. The clue is the six lugs or terminals, arranged in a 2x3 grid. That makes them a pair of common DPDT units. Although they are overkill for the job, they were cheap and plentiful, manufacturers bought them by the carload.

Red and black are the two coil leads. By convention, one side is grounded (usually black) for the sake of not having to run two wires everywhere. The green wire is indeed grounding the pickup's case, no harm in that. The magnet itself is not at issue, it can either be grounded or not, that won't affect any hum or buzzing noises.

When it comes to having 2 volume controls and 1 tone control, that's a bit of a crapper. Most guitarists don't like putting the tone control between the volume control and the output jack, they feel it harms the tone whenever one or both controls are turned down. Myself, I'm OK with it, but what I'm saying here is, I'm in the vast minority. ;D

You may be better off to consider a different scheme entirely. Perhaps using one control as a master volume, another as the master tone, and the remaining one as a blend between the two pickups, when both are selected. Or you might yank out the pot and install a rotary switch, wired to give you several tone capacitor options ala Gibson's Varitone circuitry. Or just not have the third control do anything at all, like I did with my axe. I pulled it all the way out, and inserted a small chrome plug into the hole. Looks pretty good, if I do say so myself.

Seeing as how no one else has posted a fresh diagram of what could be considered 'standard' wiring, I'll see what I can whip up tomorrow morning. I'll try some other image hosting service, probably photobucket.......... it's a cinch that Filecabin ain't coming back to life in the near future, like this decade. Shame, when they were working, they were good, but they didn't understand how to take care of their gear, and it constantly failed. Oh well.


sumgai

[sepultura999]

Thanks. The blend idea sounds pretty good. Either that, or just have both pickups use the same tone. I never adjust the tone anyway. It's always at full.

The switches don't have 6 lugs. They have 3 in a 1x3 grid. Which is why I believe they are on/off, but still possible being on/on right?

Thanks very much for taking the time to make a diagram. I'm going to attempt one myself, and since I am new to this it may need correcting lol.

-Jamie

[sumgai]

Jamie,

Oops, my fault, I should have looked again at that diagram just before my last post.... yes, there are only three terminals, all in a line, so it is a SPDT - Single Pole, Double Throw. That's an on-on switch, and like I said before, it was (and still is) dirt cheap.

The problem with trying to make one tone control work for two pickups is that there will be some sort of compromise going on. In order to isolate the two pickups from each other, you'll have to place the tone control after the volume control. Many players here don't like that idea, for reasons already mentioned. One alternative would be to install a tandem control, which is two pots connected together that share the same (single) shaft. But then, you can't control the tone of each pickup individually. Sigh.

One other possiblity would be to use a concentric pot instead. That's a pair of pots joined together again, but they have separate shafts - each pot can individually control it's own pickup. But now you need to find knobs made for this configuration, and it's a sure bet they won't be the same as what's already on the guitar. Hmmmm......

OK, let's see how you feel about that idea.


sumgai

[sepultura999]

When is it an on/off switch? Also, what would be the purpose on a guitar like this for an on/on switch? I'm guessing the les paul switches are on/on/on right?

I am about originality, and this is why I am wanting to keep it as close to original specs. as possible, whether it compromises tone or not is okay (which is why I have another 3-4 electrics). This is, by the way, a 60s japanese teisco, so to some ears it does compromise as being the "vintage tone". I guess they designed it with a jazz bass in mind.

static.zoovy.com/img/guitarelectronics/-/wduss2101

I am not knocking your ideas at all. I do appreciate them, and would consider them if this were some custom made/built/expensive guitar, but for a 75 dollar beater, it's gotta sound beat. More cowbell.

EDIT: What about this for a schematic. The possibility of it being wrong is a good one, since I am new to electronics. I borrowed the jazz bass schematic.

img130.imageshack.us/img130/3986/wduss2101ok0.jpg

-Jamie

[sumgai]

Jamie,

Your schematic is correct. It uses the 'post-volume' tone configuration, like we've already mentioned. It also wires the volume controls 'backwards' - the input is on the wiper, and the output is on the outer terminal. This effectively isolates the two pickups from each other - turn one of them down, the other is unaffected.

When is it an on/off switch? Also, what would be the purpose on a guitar like this for an on/on switch?

Take a look at the two switches on that diagram. They are SPDT, aka on-on. But if you don't hook up any wires to one side, what'dya think the net result would be..........

I'm guessing the les paul switches are on/on/on right?

Yes, in a manner of speaking. Actually, that type of switch is DPDT, with a common on position, the center. Each side is off for one of the pickups, but it's still on for the other pickup. There are a couple of diagrams in the Schematics sub-forum, if that's not clear. Try ChrisK's Electronics Templates, for starters, but there are others scattered around the nest.

I am about originality......

Don't worry, restoration to the original appearance is OK, even for a Tiesco. We've all got a weak spot in our hearts for some $50 "beginner's instrument" that we first played on, and they still need love too! ;D

HTH



sumgai

[sepultura999]

Thank you very much for your help sumgai. And of course, everyone else who also contributed. I'll buy the materials in the next few days to shield and rewire and resurrect the ol' mighty Sears teisco. It might look cool when played with a Digitech metal master

I'll still keep an eye on this thread in case anyone has any concerns BEFORE I wire up this guitar.

-Jamie