Fender

Fender Blues Junior Puts On A Light Show

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The Unbrokenstring Crew is amazed at the tough life that this tweed Fender Blues Junior has endured. Yes, it doesn’t work at all. Can we bring this poor thing back to life?

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Brian salvaged this amp from the curb in front of a house in North Carolina while volunteering in the cleanup following Hurricane Florence in 2018.

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Water damage is clearly evident on the tweed fabric, with stains and mold inside and out. The glue holding the fabric on the amp has failed, particularly on the bottom half of the cabinet.

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Starting from the bottom up, we use hide glue to stick everything back down. The lacquer coating on the tweed fabric has saved it from completely disintegrating.

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We are employing hide glue because it is not water based; we don’t want to make the wood cabinet swell any more than it already has. The hide glue can be easily cleaned up afterward, even after it dries, with warm water and a rag.

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Here, we’re removing the chassis. Fortunately, the rust is not too bad on this chassis.

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Someone has been here before, and they probably didn’t have a Fender employee badge.

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Too much heat and rework has destroyed the plated-thru holes in the circuit board. We can repair this.

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The connections (called ‘nets’ in circuit board parlance) are restored with small bits of stranded copper wire, tinned and soldered in place.

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The heart of any tube amplifier is the output transformer. It bridges the gap between high voltage power, tubes, and the loudspeaker. This HiPot (high potential tester) is measuring a complete failure of the insulation between the primary plate circuit windings of the output transformer and the secondary loudspeaker windings. Surprisingly, the loudspeaker is fine!

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Hidden on the back side of the chassis, the output transformer has lived. And Died. Alone. In The Dark.

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Fortunately, The Unbrokenstring Crew has a supply of original parts for boutique Fender amplifiers and clones, from Texas Amplification stock. This nice example of original Fender iron fits perfectly on this chassis.

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Testing the 6BQ5 / EL84 tubes, on the other hand, produces a light show. The purple glow is ionized gas inside the tube, and the blue lights hitting the paper behind the tube are beams of uncontrolled electrons.

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The red filaments are the only colors that should be there. After these pictures were taken, I had to replace the socket adapter on my TV-7U tester because it melted internally. The rest of the tester is fine and was re-calibrated – with a new socket adapter.

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After the light show from testing the tubes, each section of the amplifier is tested separately, in order to discover any other collateral damage from either the water or the failed output transformer. This amp will be Good To Go once the glue dries!

.Thanks for reading all the way to the bottom!

CONTACT – David Latchaw EE
281-636-8626

Fender Blackout Strat Becomes Even More Classic(al)

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The original neck on this MIM Black Strat was made from wood that tended to twist when the string tension varied, either because of temperature changes or when employing different string gauges. It’s now time to take this guitar to the next level, and make it an iconic Blackout Strat

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The neck will be retired to another instrument.

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This instrument was built in 2006, which happened to be the 60th anniversary of the founding of Fender Corporation.

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The neck is off and headed to its new home.

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David Gilmour’s Blackout Strat has a maple fret board. This instrument will get a new maple neck, with a 59 ‘C’ contour and an almost 2 inch wide nut. With light strings, this guitar will feel like a nylon-stringed classical guitar.

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The aftermarket Fender tuners are lined up with the machinist’s rule and tightened into place one by one.

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These tuners are ‘locking’ tuners, which positively grip the end of each string in a clamp. This is necessary on this instrument because of the very light gauge strings we will be using.

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Head stock and nut are ready to go.

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The middle pickup appears to be not working. Let’s take a look inside.

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Sure enough, there is a broken wire inside the pickup cover.

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The break in the wire is literally in the very last turn! So one turn is un-spooled and threaded through the eyelet where it belongs.

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As was done at the factory, the wire end is pulled through the eyelet a few times and soldered in place.

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The middle pickup is tested and is right where it should be.

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The Classic(al) Blackout Strat is strung with 7 gauge strings; Yes, not 12s, not 10s, but with Billy Gibbon’s own Dunlop Reverend Willy Extra Light Electric Guitar Strings, .007-.038. With the proper setup, this instrument has the play-ability and feel of a nylon-strung classical guitar. Thus, we have the Classic(al) Blackout Strat.

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Thanks for reading all the way to the bottom!

CONTACT – David Latchaw EE
281-636-8626

Fender MIM P-Bass Gets Upgraded Pickups

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A famous Houston Jazz Cat sought out the services of The Unbrokenstring Crew after hearing about us by word of mouth. This instrument was at home on the stage and in the studio, but just needed a little something more. Could The Unbrokenstring Crew supply that ‘little something more’ and get it done before this Friday’s gig?

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This instrument was a dead-stock, straight-ahead jazz bass, just a little funk added in for fun.

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We will reuse the strings, so they are just pushed back through the bridge to get them out of the way. The original bridge pickup is already loose from the body.

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A peek under the cover shows the smooth, unscrambled, automated winding used on these factory pickups.

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To access the neck pickup and get to the wiring more easily, the pick guard is removed.

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Black and white wires go to the neck pickup. So far, so good.

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And, black and white wires go to the bridge pickup. We need to keep all these wires straight. Or gently curved, as the case may be.

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The burned insulation and cold solder joint on the tone pot tells me that the factory wiring was done in a hurry. The Unbrokenstring Crew is in a hurry, but not this much of a hurry.

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The original neck pickup ohms out at 5.14k ohms.

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The original bridge pickup is not that different, measuring 5.51k ohms. The original pickups were labelled and returned to the owner.

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Our Jazz Cat chose these pickups for his instrument.

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Rio Grande pickups are built here in Houston, Texas. FYI, for the last five years, customers of The Unbrokenstring have asked to have Rio Grande pickups installed in their instruments more than any other brand.

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The Unbrokenstring Crew is curious about how these new pickups measure up. On the screen of the Fluke meter is the resistance reading of the new neck pickup. A lot of wire is used to make this pickup!

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This is the resistance of the new bridge pickup.

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Wiring for the bridge pickup is snaked through the bore in the body, along with the cavity ground wire. The pick guard does not cover this part of the instrument, so cavity wiring needs to be tunneled through the body.

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The bridge pickup settles into its new home.

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Wiring the neck pickup is a little easier as the control route extends to the neck pickup cavity route. With the wiring done and everything temporarily in place, a quick sonic check is performed with my Massive Marshall Full Stack.

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The J-Bass is reassembled and ready for re-stringing.

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If you look closely, the brand name on the pickup covers can be seen. Pickup height is approximately same value as was used to install the original pickups, but our Jazz Cat already has his #1 Phillips screw driver ready and will set the ‘just right’ height by ear.

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Thanks for reading all the way to the bottom!

CONTACT – David Latchaw EE
281-636-8626

Fender Vibro Champ Combo Amp ‘Almost’ Lost to Hurricane Harvey

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Texas Amplification, operated by the late Darryl Shifflett, built some of the finest Fender Blackface clones available. Much of the inventory of Texas Amplification was subjected to the flood waters of Hurricane Harvey. This newly-completed combo amp was high enough to escape immersion, but did not escape the subsequent rain, humidity and condensation. Could the Unbrokenstring Crew make this new unit like-new again for its new owner?

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The nickel plated feet and corner hardware are new, but a light coating of rust from the screws has leached onto the hardware. The Tolex covering appears to be unaffected by the water.

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Here’s a close-up of the rust. Not a big deal, but this triggers my OCDC (like obsessive-compulsive disease with a bit of AC/DC tossed into the mix.)

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The back panels of the amp are held on with the Correct screws, but they are showing signs of iron rust as well.

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This back panel is plywood. It had been wet but had been slowly drying out and was no longer warped. Surprisingly, the Tolex covering was still glued in place.

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This bit of Tolex covering, however, had become unglued.

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The Jensen loudspeaker was high and dry, but we’ll check it for any damage.

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The loudspeaker is more-easily inspected by removing the baffle board.

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With the baffle board out, it’s easy to verify that everything is in good shape.

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More importantly, no apparent water damage had occurred here! The Unbrokenstring Crew is fairly certain that this amplifier was at least partially submerged at the height of the flooding. This loudspeaker and grille cloth appear unaffected!

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Rust Biox is a tool of the museum curator. When old objects are carefully cleaned and restored for display in a museum, such as old weapons or other artifacts, Rust Biox slowly removes iron rust while preserving the un-oxidized material under the rust. This was once sold in the United States as an automotive rust remover, but did not become a ‘hit’ and was removed from the market. The Unbrokenstring Crew, however, is just cool enough to have a source.

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After each item is processed with Rust Biox, a water rinse and hot air dry prepares it for re-use.

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The feet of the unit are nickel-plated steel over a rubber bushing. Here, the bushing is separated from the metal foot for processing.

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These screws hold the feet onto the bottom of the amplifier cabinet.

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The metal feet are restored. Next, the Rust Biox will remove the rust stains from the rubber feet.

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Interestingly, this line may have been the ‘high water mark’ and so this unit could have been partially submerged. Furniture polish will clean and condition the Tolex covering to like-new condition.

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Heat from the hot air pencil softens the Tolex adhesive. The hot Tolex is pressed into place and allowed to cool.

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The hot air pencil has done the trick! This cabinet appears to have never been wet.

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The electronics are brand new, with no signs of water damage or corrosion.

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The Fender Vibro Champ is a single-ended Class A design, a low-parts-count, simple-to-build amplifier with surprising response and tone.

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All magnetics used in Texas Amplification products are procured through Mercury Magnetics. Top-of-the-line!

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The violet jewel in the pilot light tells us that we are ready for business!

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All back together, this amp is running a four-hour-long burn-in to verify that it is 100%. …And dry out anything still wet. This unit was delivered to its new owner, who promptly placed it in his recording studio.

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Thanks for reading all the way to the bottom!

CONTACT – David Latchaw EE
281-636-8626

Squire Jagmaster Gets a Total Make-over And Then Some! Part Four of Four

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In Part Three of this project, The Unbrokenstring Crew installed a unique cut-out switch in the pick guard of this guitar. One more thing… Now that the instrument is play-able, the original plastic Squire nut is cracked. Grrrr…

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The old Squire nut came out in pieces.

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Let’s make a new one from Vietnamese water buffalo bone. The blank we’ll use today is shown above the old Squire plastic nut.

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Not to brag or anything, but these bone nuts are truly a renewable resource that I am privileged to legally import from overseas. CITES can go bite it.

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The eighth inch chisel easily cleans whatever glue Squire used to install the original plastic nut.

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This slot is ready for the new nut.

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Sorry, that’s as clean as I can get it.

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The new blank nut is thickness-sanded to fit the slot. I’m doing this by hand because the blank is very close to the proper dimensions to begin with.

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The inside radius is established by using the actual neck as a radius block.

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The side contour is also established by hand, on the actual instrument.

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The actual height of the fret wires is measured in order to calculate the depth of the string slots. This dial indicator measures the installed height of the fret wire above the finger board.

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Here, we’re gluing the new nut right to the finger board using hide glue. A water-based adhesive could cause the wood to swell; shrinkage over the next few months as the wood dries out would throw off the accuracy of the nut slot depth. Can’t have that!

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The old nut is used as a template to establish string spacing. A couple of old strings are used to align everything.

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Now that we know the fret height, string gauge, and string spacing, we can begin establishing the string slots. At the nut, the string slot depth is constant across the radius of the finger board, regardless of the string diameter.

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With a set of old strings in place, the top of the nut can be quickly contoured so that the top of the nut will not protrude above the strings. The geometry of the top of the nut is established in part by the diameter of the strings, which is, of course, not constant across the radius of the finger board. This three-cornered triangular file belonged to my father.

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This old triangular file is just the thing to contour the nut further, smoothing out sharp corners and preparing the nut for polishing.

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Note that the string centers are just below the top of the nut, and that the top of the nut is no higher than any string.

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This is the instrument, as delivered. The Vietnamese water buffalo bone is a spectacular material for musical instruments: incredibly hard, uniform throughout its bulk, and capable of a fine polish without additional waxes or oils, making a visually attractive nut and providing a stable, polished string slot that allows for smooth and stable tuning without binding or sticking. What more could you ask?

I think we’re finally done with the Jagmaster Make-Over!

Thanks for reading all the way to the bottom!

CONTACT – David Latchaw EE
281-636-8626