Epiphone Dot Gets a Customized Bigsby Tremolo

Matt with My Twilight Pilot lusted for a black Epiphone Dot with a Bigsby tremolo assembly. Could the Unbrokenstring Crew rise to the occasion and make it happen?
It don’t get mo’ prettier than this!


The Bigsby needs a small modification, so that the tremolo bar can swing over the strings.  Here, the Bigsby is disassembled so that the modification work can begin.


This piece limits the swing of the arm.  So, we will carve on this to change the limits.  We don’t like limits.


After the carving, the metal is sanded to a uniform satin.


Successively finer grits remove the scratches from the previous operation.


This metal polish is made in Germany.  The Unbrokenstring Crew uses this stuff to polish fret wires.  Likewise, it will polish this Bigsby so that it gleams.


We’re just about there with the modification.  It can stand a little more carving.


The tailpiece is centered on the centerline of the strings, not necessarily the center seam of the lower bout.


When the body of the Bigsby is correctly positioned, there are two places where the metal touches the finish of the guitar.  While we are adjusting everything, some painters tape protects the finish.


We are committed at this point.


Two strings are installed to tension the Bigsby into position.  The location of the two additional screw holes are determined so that the whole assembly is straight with the neck before the holes are drilled.


This drill bit is in a spring loaded shell, which forces the actual bit to be in the exact center of the hole.


The strings are ON and now we can proceed with the setup of the Bigsby. See the small nylon washer where the spring fits?  This is an essential part of the setup.


String tension lowers the height of the tremolo bar.  We need to be in tune before doing much more of the setup.


The StroboTuner is spinning away while we tune and set the intonation of the instrument.


What is this?  We have a couple of screws that are having an acetone bath.  Why do you ask?

While we’re working on the guitar, these strap locks are going onto the guitar.


This is the half of the strap lock that goes on the strap.  Both sides are shown.


Those screws that were washed in acetone were painted with black lacquer, and cover up the inserts in the body where the original stop bar was held.  Pretty, isn’t she?

Thanks for reading all the way to the end!

CONTACT – David Latchaw EE


Gibson Les Paul De-ghetto-izing and Rewiring

Quyen found this 2013 Les Paul Custom Lite on Craigslist, and purchased it from a church musician.  The instrument was everything he wanted, except the controls were not the traditional Les Paul controls that he was familiar with.  Could the Unbrokenstring Crew make the control configuration a little less ‘ghetto’?  Let’s see what we can do!

This instrument is really top-drawer.  Bound neck and headstock, gold hardware, totally pimped out!  The body is thinner, partially hollow, and the back of the instrument is contoured to feel a little more comfortable.


Here’s the rub.  The coil splitting duties are performed by this mini-toggle switch, which takes the place of the second tone control.  The owner wanted the ergonomics of the Custom Lite instrument but with two tone controls.


The control cavity is under this plate.


To simulate single coils, one side of each pickup coil is grounded.  The ground wire has yellow insulation.


With one tone control to rule them all, this little blue capacitor and the control under it is the whole tone circuit.


This pic just documents the bridge ground wire.  None of this needs to be altered.


If you compare this control cavity with other Les Pauls, you can see that it is much shallower, because the body is thinner.  Otherwise, it is not hard to visualize a two-volume, two-tone setup here.


To preserve the ability to go single-coil, a tone control with a push-pull pot is evaluated.  Here, a drawing is made of the actual cross-section of the guitar body at the instrument cavity, and the exact dimensions of the push-pull pot is recorded in the notebook.  Making this modification fit properly will require some careful gun-smithing.


The center of the hole where the mini-toggle switch originally lived is in the correct location for the second tone control.  Here, a stepped bit is used to carefully enlarge the bore in the body to accommodate the push-pull pot.


The inside of the hole is cleaned up a bit with the stepped bit.  The loose wires are taped out of the way and the finish on the guitar is protected with blue low-tack painters’ tape.


The bare maple exposed by the stepped bit is refinished with some appropriate stuff.


Pushing on the felt tip of the pen dispenses black lacquer.  This step is not entirely necessary, because none of this will be visible, but there is no sense in leaving bare wood exposed to Houston humidity.  And I’m OCD.


The threaded portion of the push-pull pot is long enough to work in a Les Paul body.  However, the switch portion is nearly too long to fit under the control cover.  Likewise, we will use another nut to get the control knob height to match the height of the other three knobs.  We have some fiddlin’ ahead of us.


The three bent leads on the potentiometer were bent a little more to keep them away from the edge of the spot-faced recess in the body.  You can see this by comparing this picture to the previous one.


This tang provides mechanical support for those instances when this particular switch is used on a printed circuit board.  But, it extends past the end of the switch.  So, it has to go.


The tang is gone.  The two fingers that hold the end of the switch housing in place were pressed down.  This is about as compact as I can make this assembly.


The paint is dry!


The switched potentiometer is mounted, and the height of the shaft is adjusted so that, when the knob is installed, it will appear at the same height as the rest of them.


The owner wanted the vintage ’50s wiring for this instrument.  Already, we are about 3/4ths there.


This horrible solder joint was almost certainly done at the factory.  I can’t let this go out of the shop like this!


These orange 0.022uF caps are just the thing to match the 50’s wiring esthetic.


To tie the switched potentiometer body to common ground, I am soldering the ground wire to the interface between the pot and the switch.  That is a weak place that can use all the support it can get.  Just looking at the long haul, folks.


The yellow ground wire is added, and the original switched wires from the pickup windings were transferred to this switch.


Now this looks more like a 50’s Les Paul wiring cavity.  No circuit boards here!  The cavity cover fits without interference.


More OCD-ness.  The output jack stuck out too far.  These washers were redistributed and a nut added inside.  I feel better now.


Does this look factory?  Mission accomplished.


This Cragislist instrument is a real winner!


Thanks for reading all the way to the end!

CONTACT – David Latchaw EE

JR Beck Six String Bass Blend Pot Adventure

Billy said that he really liked this bass, but the blend pot was coming loose and something electrical was intermittent inside the instrument. Could The Unbrokenstring Crew look it over and make it stage-worthy again?

In literary circles, the term “vanity publishing” is often applied to authors who self-publish their own works. The JR Beck line is a ‘vanity-built’ line of musical instruments, wherein an individual approaches an instrument manufacturer to build instruments under a new name. This bass likely came into the world as part of a contract with a Korean manufacturer.


The neck is straight and the frets are level.  This is a player’s six string bass.


The head stock shape reminds me of an Ibanez profile.


The Grover tuners are really nice.


Someone has been here before.  This screw is too long for the hole.


Just how deep does the hole need to be?  It needs to be THIS long.


We will bore this hole down to the tape go get the length we want.


I can find no markings on the preamp electronics.  The rest of the wiring is a mess around the blend pot.


The duct tape did NOT come from Korea.  Why not get someone who can do this sort of work cleanly, like me?


The blend pot is a hack job.  The rest of the wiring is probably as it was from the factory.


Use more solder if you don’t solder it right the first time.  The solder has actually flowed inside the unit and mechanically interferes with the rotation of the wiper in one of the sections of the control.


We’ve removed the wires from the blend pot.  The cables with the green and yellow jacket come from the pickups. The cable with the white jacket wire goes to the active electronics.


Some RTV was used in an attempt to stabilize the front face of the blend control and keep it from moving when the knob was twisted.  What a mess.


As the control moved around, it scored up the wood body of the bass.  No pick guard on this unit.


To stabilize the wood and prep to mount a new control in a stable manner, a Forstner bit is employed to create a flat-bottomed ‘spot face’ in the wood cavity.  There is some risk of penetration, so we’re going slowly at this point.


A flat-bottom hole is bored without incident.  A steel washer will be epoxied into the body to fully-support the new blend pot.


The new blend pot comes with a couple of flat washers.  I’ll use a lock washer and another nut to set the height of the control so that the knobs are all installed at the same height on the face of the guitar.


A blend pot is a pair of “M” taper potentiometers, which allow one pickup to be faded out as the other side gets louder.  As the control reaches each limit of its travel, the other pickup is electrically ‘cut out’ of the circuit.  In a way, it acts as a selector switch at each end of the travel, with a continuous blend of the two signals in between.


The cross wiring is done with solid 20AWG copper covered with Teflon tubing.  The pickups are wired on the end.


This control has an index pin.  We will cut a slot in the steel washer to ‘catch’ this index pin and hold everything in place.


Initial tests showed that the signals from both pickups were literally ‘grounded’ when the control was set to either limit.  We need to install range-limiting resistors to each end of the controls so that the selected pickup is not grounded at the end of the potentiometer travel.  This is a blend pot, not a kill switch, after all.


It is an easy task to break the connection to ground and install a fixed resistor.  The proper value depends, in part, on the internal DC resistance of each pickup.  It will be easier to discover the proper value empirically.


The box with all the switches is sometimes called a ‘design box.’  The proper name is a ‘resistance substitution box.’  Various values of resistors are switched into the circuit until the desired result is obtained.  Here, we are choosing a resistor value for one side of the blend pot.  Too low a value attenuates the signal.  Too high a value causes hum.


Here is the fixed resistor for this side of the blend pot.  Note the use of the Teflon tubing to keep the signals under control.


Here is the new control installed in its new home.  I am satisfied with the electrical results of this experiment.


The original knob works nicely with the new control.  Note that the knobs are all the same height off the body of the bass.  Another thing I like about this bass is, look at that massive bridge saddle and end block!  The Koreans really know how to do it right.


Jacob takes the finished bass for a spin.  He wants one!

Thanks for reading all the way to the end!

CONTACT – David Latchaw EE

The Prodigal Guitar – Harmony H80S Olympic Strat Comes Home to the Fortunate Son

Jason Becerra of Cathedral Records is our guest blogger today. He shares an incredible story about how this immaculate Harmony H80 Olympic Strat was won, was lost, and won again. Enjoy the trip!

“I was writing songs long before I could play an instrument. I had notebooks full of lyrics and I had melodies for each song.

“My parents, like many in that era, put me in piano/organ lessons at the mall where they bought a Lowery synth organ for me. I learned how to play ‘When the Saints Go Marching In’ with one hand and I have fond memories of the old woman whose pleasant teaching style was metered only by the not-so-faint aroma of liniment and hard candy. After my year-long course ended, I received my certificate of completion, and that was that.

“A couple years later though, my dad brought it home. “It” was a white on black Olympic Strat copy with a matching head stock. It was the coolest thing in our house and I, of course, was discouraged from messing with it because I had a track record for destroying guitars. When I was about 4, (and I have no recollection of this, I swear) I did my best Pete Townsend impersonation on my dad’s beloved acoustic guitar.

“By the mid-to-late 80s, he’d decided to get himself a new guitar, this time an awesome electric which was purchased, used, at a local pawn shop under the guidance of one of his many musician friends.  I was on a heavy diet of Elvis, Buddy Holly, Jerry Lee, Tommy James, Mamas and Papas, the Turtles, Dylan, Gary Lewis and the Playboys, Gerry and the Pacemakers and of course…the Beatles and the Beach Boys.

“Now, I don’t know if this was by design or by accident, but I experienced the music of the 50s and 60s in the same way my dad did, in terms of age and sequence.  When I was very young I was bathed in doo-wop and rockabilly that laid the foundation for rock and roll.  A bit later, I got to the early 60s: Motown, surf and folk rock, girl groups like the Shangri-Las. Then…the British Invasion hit me with the rabid, frantic pounding beat of the Beatles’ ‘She Loves You’ and Dave Clark Five’s ‘Glad All Over.’  As the music of the era matured and gave way to albums like the Beach Boys Today! and Pet Sounds and the Beatle’s Sgt. Pepper, I too was maturing and growing into myself.

“All the while, my friends (who thought I was more than a bit strange due to my obsession with our parents’ music) were feeding a steady stream of modern music; everything from Bon Jovi and Van Halen to the Cure, REM, Information Society, the Ramones, the Descendents and of course, being in high school at the time, the early 90s music scene hit me just as hard as anything.

“All the while, that black Olympic sat in my dad’s office…just begging me to come take it.

“By 8th grade I had grown frustrated with poetry, essays and stories.  I wanted to say more.  I had more to say, feelings I couldn’t convey without something… without MUSIC.

“One evening, I grabbed his guitar and a “Learn to Play Guitar with Mel Bay Level 1” book.  I studied the chord chart for “G” and struggled to get my fingers just right and after a little while I got all six notes to ring out.  It was magical.  I was sold.  From that point it has been a truly lifelong obsession and it all started with my dad’s Olympic that was generously handed down to me as he realized what he had created in me. Haha!

“I lugged that thing EVERYWHERE.  I knew every corner of it.  I learned how to clean it, how to change strings, how to tune it and I still vividly remember learning the changes to Yellow Submarine and thinking, “Holy Shit!!  I’m getting the hang of this!”

“In 1995, I graduated high school and got a little job while attending university. I saw a shiny new Fender Stratocaster hanging in a guitar shop in Pasadena, TX. I decided to get my first “proper” instrument. I loved it. It had a fancy-schmancy humbucker in the bridge and a Floyd Rose locking tremolo and even though it became my “main” guitar, I still went to the Olympic, all the time. There was something special about it, with its maple neck, the little nick at the 9th fret near the high E string.

“Over the years I had developed a desire to have the Olympic worked on.  The pickups were sounding awful, lots of buzz, the knobs and switch were rusted, machine heads were cheap import stuff and it didn’t hold its tune quite as well as it used to.  It was old when I got my hands on it and I had certainly put it through its paces so it was showing its age.  My friend soldered a random piece of wire onto the back of the guitar inside the cavity where the springs attach…onto the middle hook.  He said it would help with the hum…not so much but he had been playing longer than I, had a jam room in his garage, and owned a van.  Who was I to question?

“By the early 2000s, I was anxious to get someone to work on my Olympic.  I met a guy and I gave him the Olympic with a set of machine heads, a set of Fender hot vintage noiseless pickups, new knobs, and a new switch and asked him to do the work for me.  He said it would take a few weeks and he’d call me.

“Months went by…he stopped working at the store where I met him.  His phone stopped accepting calls.  Nine months go by and I get a random call from him saying he was sorry for being out of pocket but that he was almost finished.  I begged him to let me come get my guitar, no hard feelings; I just didn’t want to lose my guitar.  He assured me he would not fall off the grid and that he’d get in touch with me in a week or two.

“I never heard from him again.  That was 2003.

“For over 10 years, I scoured craigslist, EBay, Guitar Center, pawn shops, everywhere I could think of looking for this Olympic guitar.  No one had ever heard of them.  Truth be told, I had the only one I had ever seen!  No luck.  There is ONE post on a random website where a guy shows a picture of his red Olympic.

“I actually signed up for the discussion board and sent him a private message asking if he’d considering selling it.  No response.  My black Olympic Strat copy had become my unicorn.  Until a couple months ago…

“I was home sick, lying in bed with a nasty stomach bug.  I was looking at Craigslist for my guitar when all of the sudden, I saw one!  I immediately called the guy and said “I’m on my way.”

“I took another look at the guitar and my heart sunk…it wasn’t the same one.  This guy had a blue one…mine was black. Well crap.

“I told him to forget it.  For a couple weeks I was on the fence.  What if I never see another one?  Isn’t blue close enough?!  Am I ever really going to find MY guitar again?  Shouldn’t I just settle for the same model?  I decided to settle. What the hell.  I’d given up.

“I drove over to where the guy had the guitar and picked it up.  He was a nice older man who does garage sales to augment his retirement income.  I asked where he got and he didn’t really remember…his son got it from some guy.

“I took it home and was immediately plugged it in.  Nothing. It didn’t work.  Damn it.  All this and now I can’t even play it! But I stared at it…and I held it and I examined it.

“Curious…there’s a nick right at the high e-string,  9th fret. Hmm…

“The sticker with the “serial number” is scrunched up in the same way I scrunched mine up.  Wait…this guitar isn’t blue! This guitar is BLACK.  Someone put a blue coat of paint on this thing!

“Could it be? Naaaaaaaaaah.  What are the odds right?

“So I called my good friend David Latchaw to give this thing some love.

“While David is working on it, I go back on the trail.  I start posting on Facebook and I get a name of the guy I gave my guitar to in 2003.  I found him on Facebook…..and wouldn’t you know it, he’s “friends” with some friends of mine!  All these years, he’s been right freaking there!

“I reach out to him and he explains what happened all those years ago.  He stopped doing repair work and gave everything he had to an associate of his who was supposed to call customers and return the gear or finish the repairs. Now I had a NEW name.  I started hunting that guy down.  I found a trail of hacked or shut-down websites, bad reviews on forums about “what happened to that guy?  He used to do great work!  Now he’s fallen off the face of the earth!” Apparently this guy fell into some troubles, and that was that.

“But I know he had it and pretty much just sold everything he had to whoever wanted to pay for it.

“Could he be the guy that the old man’s son bought this guitar from?

“David comes back with my new (old?) Olympic and of course it plays like a million bucks.

“As we were talking I asked if he opened the back panel.  He says yeah. I ask what he found.

“He said, “darndest thing, someone had taken a piece of random wire and soldered it to the middle claw… I’ve seen this for grounding, but never on the center claw like that.  That’s a new one.”

“Well folks…long story short…sometimes, what goes around….really does come back around.

“I bought my original guitar 12 years after losing it…and didn’t even realize it until it was back home in my hands and David had worked his magic.  While it was away from me, the machines head actually got installed but the original pickups were left in.  I guess whoever down the line decided to use the pickups I bought on something else.  It also got a paintjob!

“David gets a huge thank you for all his incredible work on this guitar and all the previous work he’s done and the future work he’s going to do.  (I’m going to keep you busy my friend.)

“My wife gets a huge thank you for indulging my music obsession for all these years and never once putting her foot down when I say “I need to get this guitar” even though I always say that’s the last one I’m going to buy.

“My Dad gets the biggest thanks of all…for filling my childhood with music, for never hesitating to lend me his records, for always playing “name that tune” when we were in the car (he quit playing when he said I became better than him) and for the black pawnshop strat-copy Olympic guitar that started me on this little journey as a wannabe songwriter.

“I AM a fortunate son.

“My advice to all of you players out there…it might be tempting, but never let go of your gear. Don’t trade it, don’t sell it and don’t give it to anyone you don’t have 150% confidence in because you could come to regret it for years and years to come.”

Jason Becerra

You have heard the news. Now, here’s the rest of the story.

This head stock just oozes ‘vintage’ and we are not to be disappointed!

We need to replace the controls, including the switch.

Some of the bridge screw holes in the body were stripped, or the screws were missing.  This is an easy fix.

The correct screw for the bridge is an inch long.

We believe that this guitar was painted.  No shortcuts were found in the blue finish.

The original controls were shot.  These are the smaller, 16mm controls often seen on imported guitars.

This is a ‘treble bleed’ capacitor, which keeps the treble from disappearing as the volume control is dialed toward zero.

This is the tone capacitor, that works with the tone control to form an RC network that shapes the frequency response of the guitar.

The tone cap is a polyester film part that checks good.  We’ll use this part again when we reassemble the guitar.

The selector switch is shot.  Jason wants a switching arrangement that selects just the bridge pickup, the bridge and middle pickup, all three pickups, the middle and neck pickup, and finally just the neck pickup.  The factory switch won’t do that, so we’ll use a Super Switch in place of this unit.

The original single coil pickups are in excellent shape.  Each one is labelled with orientation and position.  Then, the pickup wiring is clipped cleanly from the controls.

These pickups will be reinstalled with the new controls.  For now, we will remove them and set them aside.

This is the new Super Switch.  We have a couple of issues.  One, the mounting holes in the Harmony pickguard do not align with the screw holes in the Super Switch.  Also, the lever slot in the pick guard needs to be longer to allow the switch to move fully through all five selector positions.

Here, I get an idea how long the slot in the pick guard needs to be.

This is how long the slot in the pick guard actually is.

Rather than remove a lot of material from a priceless pick guard, we can narrow the selector arm on the switch to not take up quite so much room in the pick guard slot.

Here, I’m reshaping the selector arm on the switch with a mill file.

If you compare this pic to an earlier picture, you can see the material removed from the arm of the switch.

Rather than drill new holes in the pick guard, I’m locating the centers of the existing pick guard holes on the body of the Super Switch.  Again, I do not want to modify the vintage pick guard if I can help it.

The center punched locations of the pick guard holes were drilled for a 4-40 tapped hole.

Here we can see how the new mounting holes are located with respect to the old ones on the outside ends of the switch.

The holes are tapped to match the mounting screws.

I think this is going to work well for us.

The new switch is trial-fitted to the pick guard.  The length of the mounting screws is examined closely to see if they interfere with the action of the Super Switch.

The ends of the slot for the switch were ever-so-slightly widened to allow the switch lever to move fully to each position.  Here, I’m using a guitar nut file for a low E string to shape the slot.

The heads of the new mounting screws were turned down slightly to allow the switch arm to clear.

We have full switch travel from end to end.  This will work well for us!

The potentiometer mounting holes were widened to 3/8ths of an inch to match the bushing diameter on the new controls.

The new controls are full-sized 24mm parts intended for vintage Fender Stratocasters.  This one fits ‘just right.’  I went with 250k pots because the guitar would be very bright-sounding using the original tone cap and 500k pots.

Here are the new controls, set to the proper shaft length for the Fender knobs.

These are all 24mm controls, so I verified that they would fit in the original body routes.  They do!

I stripped off the aluminum shield tape.

I replaced the shield tape with copper.

Using the copper tape, I could now tie the body of the pickups to the same shield as the controls.

The copper solders quickly, without melting the pick guard underneath it.  This ensures that the copper plane is continuous.

Here is the new mechanical layout of the pick guard.

With the new controls mounted in place, the wiring scheme for the five-way switching could be implemented.

The gray cables come from the pickups, and are wired to terminals on the Super Switch.

Wiring for the volume and tone controls is done with solid silver-plated 26AWG copper, covered with aerospace-rated Teflon tubing.  Much of the Space Shuttle Orbiter electronics are wired this way.

This is the finished pick guard assembly.

The output jack wiring, bridge ground wire, and tremolo claw wiring (such as it is) are already attached.  The bridge is set up as a hard tail (no tremolo arm needed.)

The setup and fret polish went pretty well.

Now we have returned, full circle, to where we started. This is an EXCEPTIONAL instrument!

Support Jason’s record label!

Jason’s father Rolando is still making music and making an impact on the music world today. His radio program “Branson Now,” airs on AM700 KSEV in the Houston market. Rolando brings a unique narrative to the rich world of music as only someone of his experience and sensitivity can do.

Click here to see more about Rolando Becerra’s radio program in Houston!

Thanks for reading all the way to the end!

Contact – David Latchaw EE
Cell – 281-636-8626

How Gibson Les Pauls Lose Their GForce Tuners

I own several old Gibson guitars , so I am only passively interested in, and mildly amused at, the flame war over the self-tuning GForce system included on new Les Paul guitars.

Jacob of The Unbrokenstring Crew said “The Internet is where nuance goes off to die.” Like most topics of discussion, the flame wars over the Gibson GForce system has devolved into a bipolar, binary love/hate relationship. Perhaps, someone actually thought about the situation, and decided that they would sell more guitars WITHOUT the GForce system installed. To that end, our local national guitar retailer has received some interesting tool in the mail.

These blocks of steel have nylon alignment pins that fit in the factory tuner holes used by the GForce system. The small holes are where the headstock will be drilled for manual tuners of various makes and models.  The Klouson holes are in the wrong place, so we are only installing Grover tuners for now.

Here is the back of a Les Paul headstock with the GForce system removed. Except for the indentations in the wood where the printed circuit board traces were, you would never know that they were there… more or less…

The GForce tuner assemblies were removed from the headstock. These are to be returned to the Global Headquarters of the National Guitar Retail Chain when we are through.

Perhaps they will salvage the rechargeable batteries, or maybe they will be used for spares as these fail in the future on other guitars. Hey, it could happen!

The nylon alignment pins hold the template in place. Drilling a hole and installing new manual tuners is straight-forward.

Grover tuners, anyone?

How about some locking Grover tuners?

For the purists, here are some Klusons on an older guitar.

I will not weigh in on the flame war over the deployment of the GForce system. But now you can go to a retail outlet and find a 2015 Les Paul that does not have the GForce system installed. We’ll see how this decision plays out over the coming years.

Thanks for reading all the way to the bottom!

Contact – David Latchaw EE
Cell – 281-636-8626