Trade Secrets!

Electronics cleanup in a beautiful '58 Gibson: "Little Lefty"


Issue 154 December 22, 2011

You don't see one of these every day!
Frank at Blue Eagle Music I’d never seen a “miniature Les Paul” guitar case like this before. Inside is a rare (and small) 1958 Gibson.
Dan ErlewineCompare this mini-case to the case for my Les Paul sitting right behind it: this should be holding a tiny Les Paul! I was fascinated to see what was inside. It’s a 1958 Gibson ES-125T in 3/4 size — and it’s a lefty, to boot! Frank McDermott of Blue Eagle Music Store here in Athens, Ohio called me when he found this. The guitar’s unusual, but its problem isn’t: the signal from the pickup is cutting in and out.
Dan Erlewine, December 22, 2011
     
  Frank’s a lefty just like this guitar, so this Gibson was a great find. But when he plugged it in, what he heard was... nothing. Dead pickup. That’s when I paid a visit to Frank’s shop.
Was the pickup really dead?
I used a multimeter to check it out. One way to do this is to plug a cable into the guitar’s output jack and read the pickup by touching the multimeter probes to the other end of the cable.
   

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Multimeter and custom plug I plugged a multimeter into the jack and got a DC resistance reading of 7.86k when the volume was on 10 — but it kept cutting out and showing an open line. I figured the pots were just really dirty, or maybe the jack was bad. I took the little lefty back to my shop to remove the electronics and flush out the pots with contact cleaner.
Portable Digital Multimeter

Fun and useful gizmo. I don't like fumbling around with test probes and cables, trying to hold everything in contact while getting a reading, but I do like making tools... So I've made myself this gizmo for testing guitars: a plug with brass tubes soldered to the leads. The multimeter probes insert into those brass tubes. Here’s a link to a Facebook photo album about it:

 
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String ground wire On this guitar, removing the electronics means first removing the tailpiece in order to free the string ground wire. This wire is pressed against the metal of the tailpiece, grounding the strings to the wiring harness inside. It pulls out along with the electronics. (To get it back in later, I snaked a guitar string in through this hole and attached it to the ground wire with heat shrink tubing.)
Heat Shrink Tubing
Dirty electronics The electronics were covered with dust, hairballs and bird’s nests. I vacuumed away all of that before cleaning inside the pots — no sense in blowing this junk into them!
 
Spraying DeoxIT Spray cleaning: Wearing nitrile gloves, I gave the pots a good flush with DeoxIT, rotating the shafts to flush out the dirt. This did the trick; the loss of sound turned out to be simply due to a dirty control pot.
DeoxIT Pot & Switch Cleaner
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Brushing away dustCrumbly old tape: I used a clean glue brush to remove the oxidation from the pickup’s baseplate. There was a wrap of old brown masking tape insulating the solder joint connecting the coil’s hot lead to the braided shield output lead. That tape was dry as bone: cracked, crumbling and falling off. It disintigrated when the brush touched it. “Good riddance” I thought, and finished cleaning the baseplate thoroughly. I was confident that I could replicate the old tape fairly easily, and that was the fun part of this job.
Glue Brush
Paper tape from a cardboard box  
I tore off the thin outer layer of paper from a brown cardboard box and coated it with ColorTone platina shellac to give it crispiness and shine like the old tape.
In 10 minutes the shellac had dried enough for me to coat the underside with hot hide glue and let that dry for 35 minutes. The glue would give stickiness to my home-made masking tape.
Cut in a 3/4" strip, I had shiny, vintage, brown “masking tape” almost like Gibson used.
ColorTone Shellac
ADDING dust!Covering my tracks with dust: After crumpling it, I wrapped the tape around the solder joint and stuck the wrap together with a touch of hot water. Then I added another coat of shellac to give it a little more shine. The little piece looked a convincing 53 years old.While the shellac was still sticky, I brushed some dust onto it for a “relic” look. It’ll pass for the original tape now. I was very pleased with the look of it even though nobody else would ever see it. Sometimes I just can’t help myself: it's fun to throw in little extras like this!
Behlen Ground Hide Glue
Frank's happy! Home to papa. I took the guitar back to Blue Eagle for Frank to check it out: Frank’s happy, I'm happy, and I think Little Lefty looks happy, too!
 
Problem-solving products for this kind of work:
ColorTone Shellac
Our "old-school" instrument finish for sealing, touchups and French polishing.
DeoxIT Pot & Switch Cleaner
One-step spray for cleaning and quieting noisy pots and switches in guitars and amps.

Portable Digital Multimeter
Test continuity, AC/DC voltages, amperage, and ohm resistance of pots and pickups.

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Behlen Ground Hide Glue
Traditional luthier's glue
Mixing Cups
1-ounce plastic mixing cups, graduated for precisely measuring and mixing stains.
Glue Brush
A versatile metal-handled brush that's the right size for routine instrument gluing jobs.
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