dearmond silver foil pickup help for rescue! reposted from gtr tech forum.

[dboonelee]

Hi, I need help on this dearmond silver foil pup.
I messed it up by cutting the wire too short and am now trying to put new shielded cable on the lead and ground.
It still has the wax over the winding. I can't find the hot lead. I read that it is soldered to the base plates little notch, but I can't find it.
It has the original tape next to the notch but nothing under it.
I'm afraid of cutting the wax potting off and hacking up the winding.
So what is the best way of getting to the lead wire? Grounding is the opposite corner right?
I am not concerned with using vintage wire etc. I just want to get this working again.
Thanks.

p.s.
I'm a newby here so I'm reposting this here because it seems like the right place. right?

[52 Bill]

I can't find the hot lead. I read that it is soldered to the base plates little notch, but I can't find it.
It has the original tape next to the notch but nothing under it.
I'm afraid of cutting the wax potting off and hacking up the winding.
So what is the best way of getting to the lead wire? Grounding is the opposite corner right?

Normally the coil wire starts at the small tab which is the base plate ground. The wire then wraps around the magnet and ends under the outer tape wrap. The hot lead solders to the end of the coil wire and is wrapped under a layer of tape.

When you removed the cover the shielded wire should have been soldered on. How was it attached?

[rjb]

I had the same problem about four years ago (not a silver foil, but a DeArmond of similar design).
http://music-electronics-forum.com/t20593/
A member kindly posted helpful photos- but unfortunately they've disappeared.
Anyways...

As 52 Bill said, the coil wire start is soldered to the notched tab at the corner of the baseplate; the wire is so thin, it's almost invisible.
On my pickup, the coax cable shield was soldered to the baseplate, at the end opposite the tab.

Don't cut the wax off- melt it off.
To find the hot lead (the coil wire finish end), you will have to carefully remove the tape.
On my pickup, the coil wire was soldered to one end of a thin strip of copper; solder the coax signal wire to the opposite end of the copper strip.
Then carefully replace the tape, and pray.

p.s.
I'm a newby here so I'm reposting this here because it seems like the right place. right?

You might have better luck at Instrumentation -> Pickup Makers than here at Amplification -> Guitar Amps -> Maintenance Troubleshooting and Repair.

[dboonelee]

copper tape.

Normally the coil wire starts at the small tab which is the base plate ground. The wire then wraps around the magnet and ends under the outer tape wrap. The hot lead solders to the end of the coil wire and is wrapped under a layer of tape.

When you removed the cover the shielded wire should have been soldered on. How was it attached?

Thanks Bill,
I accidently separated the copper tape(which I kept) before I opened the pup. So the wire was loose and I didn't see the lead.
I also removed the tape before I posted, so no site of the lead.

[dboonelee]

Thanks rjb,
I saw your thread before I posted. And yes,
the pictures are gone....
Like I told Bill, I have removed the tape, which I thought was wax at first, and also yanked the copper tape off before I removed the pup cover....arg.
So you think that I should still melt the wax? And if so, all of it or just that section? And would hot glue be ok to replace it?

[rjb]

Like I told Bill, I have removed the tape, which I thought was wax at first, and also yanked the copper tape off before I removed the pup cover....arg.

I've only opened one DeArmond pickup in my life- and, as luck would have it- I wax-potted it before opening it.
So I don't know if DeArmond routinely wax-potted their pickups or not.

In addition, I'm a bit confused about what you did.
You removed tape which you thought was wax, and now there is wax around the coil?
How did you yank off copper tape before removing the pup cover? Or do you mean the upper flange?
When you say copper tape, do you mean a short strip of very thin copper- or did someone wrap the entire coil with copper tape?

Doesn't matter; I found a photo that hopefully shows what you need:

Not a silver foil, but close enough.

It's hard to see, but the paper tape starts well under the copper strip (to protect the coil from shorts and soldering heat) and wraps around to cover the splice.

So you think that I should still melt the wax? And if so, all of it or just that section?

Whatever it takes, you have to find the end of the coil wire. If you have to melt wax to do that, then that's what you have to do.
Then check the continuity from ground to the coil end (should be "several" Kohm; values vary widely for different models and versions).
Then solder your coax lead to one end of the copper strip; wrap paper tape as shown (might have to use new tape); solder coil wire to opposite end of copper strip; complete paper tape wrap.
(If not secure about doing any of this, search pickup builders forum for advice.)

And would hot glue be ok to replace it?

NOOOOOOO!
Murphy's Law says the coil wire will break at least once again.
If you've hot-glued the coil, then you'll really be SOL.
(Well, not really- you'll "just" have to cut off all the coil wire and rewind it from scratch.)
After the pickup is totally reassembled, you can pot the whole thing in melted wax (search Pickup Builders forum for details).

[big_teee]

A hair dryer works good for melting wax.
For glue drying and small wax spots, I use a heavy duty 3 speed hair dryer, I got from my wife.
Be careful on high, you may melt a bobbin or anything plastic.
As you melt the wax you can wipe it off with a paper towel.
If you want to put some wax back on it when your done, you can drip candle wax, and smooth it with the hair dryer.
Like mentioned earlier, do not use any kind of glue on magnet wire.
You can use clear fingernail polish, which should be a lacquer.
GL,
T

[dboonelee]

Thanks for your advice!
Sorry to be so confusing. I was thinking that the tape around the coil was wax and the first bit of tape that I took off was tape with waxy residue all over it. So now I know that it's tape. I've never taken a pickup apart and didn't even know that they were waxed until a few days ago and assumed the yellow tape was wax. I only knew that they were a magnet, a coil with one end grounded and the other hot, and a bobbin.
And to clear up the yanking of the copper tape, I actually pulled the wire too far before I opened it up. The copper tape that you can see in your photo that the wires are soldered too came out on my pickup when I was pulling it to get some of the insulation off for soldering , so I knew that I made a huge mistake!

But now I have the wire exposed and have to solder it to the copper tape, (or is it foil?).

A question, I have some metal splicing tape for repairing 8-track cartridges. Can I (or should I) use that in place of the old copper? Or is the copper tape still good despite not having any adhesive left? Or could it be used in place of the paper tape and maybe provide shielding for lowering hum?

Ok so no hot glue!

Anyway, you rock! That's a great photo that you sent! very helpful.

Thanks again!

[rjb]

And to clear up the yanking of the copper tape, I actually pulled the wire too far before I opened it up.

OK, gotcha. Ouch.

But now I have the wire exposed and have to solder it to the copper tape, (or is it foil?).

So, you've found the end of the coil wire? Great! Way to go.
I think the copper strip is actually very thin sheet (AKA shim stock?)- just a little thicker than foil or tape, with no adhesive.
IIRC, mine broke in half and I replaced it with a piece of copper tape from a stained glass supply house.

A question, I have some metal splicing tape for repairing 8-track cartridges. Can I (or should I) use that in place of the old copper?

I'm not familiar with metal tape-splicing tape. Is it copper? Does it take solder?
You should definitely hold onto that tape, though. 8-tracks are coming back any day now.

Or is the copper tape still good despite not having any adhesive left?

I don't think it had any adhesive to begin with.

Or could it be used in place of the paper tape and maybe provide shielding for lowering hum?

You want to wrap the coil with paper tape to protect it from shorting and physical damage.
If you then want to shield the coil with metal tape...that's another story (that has been well told in the Pickup Builders forum).
BTW, shielding doesn't lower hum. Humbucking lowers hum. Shielding lowers buzz.
Personally, I think the baseplate and cover shield the pickup pretty well, and wouldn't bother adding more shielding.

Ok so no hot glue!

Hot glue is great. Just not on pickup coils.

[dboonelee]

New quandary,
I can't see the start of the coil that is supposed to be soldered to the notch.
My fear is that it has broken off and the start is now underneath the coil out of site.
I know that you can't see it in the photo, but I just wanted you to see the end that I am referring to.

If this is the case, I think that I'm going to have to take it to a pro. Unless I can figure out a safe way to spool it off until I find the end.....
Any ideas?
Thanks again!

[52 Bill]

I can't see the start of the coil that is supposed to be soldered to the notch.
My fear is that it has broken off and the start is now underneath the coil out of site.

Looks can be deceiving, measure resistance from the outer end of the coil to the baseplate.

[dboonelee]

Looks can be deceiving, measure resistance from the outer end of the coil to the baseplate.

Well, no reading with my multimeter.

[rjb]

Well, no reading with my multimeter.

Don't give up just yet.
Did you sand the insulation from the end of the coil wire, so your probe is touching copper rather than enamel?
On the baseplate, are you probing clean, bare, shiny metal?

[dboonelee]

Don't give up just yet.
Did you sand the insulation from the end of the coil wire, so your probe is touching copper rather than enamel?
On the baseplate, are you probing clean, bare, shiny metal?

Yes and Yes.
Sanding the coil wire is hard because it is so thin that it breaks with a little pressure.

What next? A pro?

[rjb]

Sanding the coil wire is hard because it is so thin that it breaks with a little pressure.

No one said it was going to be easy...

What next? A pro?

I suppose.
You might ask in the Pickup Makers forum; some members do repairs.
(Not me- I'm just a shmoe who tries to fix his own stuff.)