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Univox with no Vox!

Here was a fun but ultimately frustrating fix.  This Univox electric was brought to me with the complaint of “no sound”.  This guitar just oozes mojo.

This picture was taken after all the work was done on it.  It was initially brought to me in pieces (PAY ATTENTION NOW! THAT’S IMPORTANT LATER IN THE STORY!)

A tip: before bringing a guitar to a repairman with this complaint, rule out the amp and the cable as problems!  But this girl really does produce no sound.  So a couple of quick diagnostic steps later, I find the problem: the pickups get no resistance reading and have no output when connected directly to an amp.  This generally indicates that there is a short or a break somewhere in the winding of the pickup.  It’s odd to have this happen in BOTH pickups at once, but we don’t know if it happened all at once because the current owner has never had this guitar in a put-together and strung-up state – he got it from the seller in pieces.

So the pickups are removed and examined.

A bit scungy but nothing outwardly wrong.  The magnets have good charge.  So one obvious solution would be to replace the pickups with new ones.  After thinking about it for a bit, I asked the client what he would like to do.  I was inclined to leave as much of the guitar stock as possible, and he agreed.  So I dismantled the pickups and stripped the old windings off the bobbin.

Then I used the Official Black Watch Pickup Coil Winder (note the capitalization which hopefully offsets the fact that it was made out of a sewing machine motor, Gatorade bottles, frayed power cord, and the lost souls of several degenerate drummers) to rewind the bobbins:

Insert dead pickup here!

Here’s where things started to go sideways.  The old plastic bobbins have deteriorated over time and no longer can stand the pressure of the windings.  They crack and buckle.

Snap Crackle Dammit

One of the bobbins is salvageable and is wound without trouble.  The one in the picture is toast.  Unfortunately, NO ONE makes replacement bobbins that will work for these pickups.  At least no one that I can find.  So I have to ingenuitize (like how I made that word up?) a replacement out of some MDF and Forbon.

Scottish Engineering at its finest

The pickup is rewound successfully.

Then begins the reassembly, and here’s where things go a bit more sideways.  When the pickguards were removed, they did what all things made of old plastic do: they shrank.

Hmf. Dammit.

It’s especially noticeable in the gap between the two pickguards.  Finding pickguard material of the right appearance to replace the entire guard is possible but difficult; additionally, the owner didn’t want to put a whole lot of money into this one, so I made a black cover sheet of mylar film and put it under the guards.  It’s passable but someone somewhere is wondering why there’s a big piece removed from their x-rays.

Roentgentastic!

Finally, the pots and switch are cleaned, the new pickups are wired in, and the whole guitar is strung up.

PAY ATTENTION NOW! HERE’S WHERE I REALLY MESSED UP!

Actually, I messed up earlier.  In retrospect, I should have assembled and strung this guitar up at the very first to make sure that it was playable.  Unfortunately, after I did all that work, I found out that the neck had a fair amount of forward bow under string tension, and the truss rod wouldn’t relieve it.  The old girl is playable with action that’s fairly high, but it won’t intonate correctly in the higher ranges.

However, it DOES make for a good slide guitar, and the newly-rewound pickups have a great bite to them that sound like P-90’s.  After confessing my flawed approach to the client, he was kind enough to pay me for the work I had done, and actually is fairly pleased with the results.

Lesson learned for this one, but it was a lot of fun.

~ by badmin on May 16, 2012.

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