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curtisa

Renovate a Pacifica

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While waiting for paint to dry on the First Build Resurrection thread, here's another rebuild of sorts in preparation for the cleanout.

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The culprit being a first generation Yamaha Pacifica 112 that I bought many years ago as a backup guitar while I was still in a local gigging band. After the band...err...disbanded, this got repurposed as a test bed for several ideas, including some additional switching to allow all three pickups (the mini toggle near the volume pot) and an Eyb Guitars Buzz Bridge for sitar effects:

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While it'd be nice to sell it as is and not spend any time on it, I can't deny that with the Buzz Bridge it would have limited appeal on the local market, so the decision has been made to remove the BB and reinstate the original Strat-style bridge. I'll also get rid of the mini toggle, to restore the wiring to stock.

The problem with this one is that in order to originally install the BB, I had to cut a section of the pickguard away to allow the oversize bridge assemble to sit properly on the guitar. With the BB removed and the original bridge replaced, it's painfully obvious how much material had to be removed in order to fit it:

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So I'm going to have to make up a new scratch plate with a recreation of the missing section around the bridge.

First thing's first, disassemble the guitar to get the original scratchplate off. The intention is to use it as a template for a replacement and approximate the missing contours to replicate the piece that was cut out. Luckily I had the forethought to save all the original components when I installed the BB, and still have the original bridge, screws and springs. Rather than remove the old trem claw, I left it in as a handy place to attach the BB ground wire. The claw was just screwed all the way forward to stop it from rattling:

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The mini toggle simply added the bridge pickup in parallel with whatever was selected on the 5-way, to give the all pickups on and bridge+neck options in positions 4 and 5 respectively. While it worked it also had the side effect of duplicating the B+M combo in position 3 and 2 simultaneously, making it pretty annoying in practice. In the end I hardly ever used the additional switching patterns, so it was largely redundant:

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All stripped bare:

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With the scratchplate off the guitar I can send it through the big A3 scanner at the office and get a lifesize copy of it. By putting it in backwards I can get crisper edges as I don't have to worry about the bevelled edge from masking the true outline of the plate:

Pac112 Scratchplate.jpg

After loading it in to the CAD software and tracing the edges as best I can and flipping it around, I can then scale it down to match the original, and add an approximation of the missing section behind the bridge pickup. There's probably neater and quicker ways of doing this, but for me this works well enough:

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Printing it at 1:1 scale gives me an opportunity to check the fit before cutting up a blank sheet of pickguard material:

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Some minor tweaks around the bridge cutout, but otherwise looking pretty close to the original, especially around the pickguard mounting screws which need to line up reasonably closely.

 

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I could go for plain boring old white plastic like the original, but why not smarten it up a bit? How about some 3-ply white/black/pearloid instead?

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I have the new scratchplate drawn up at 1:1 scale in CAD, so may as well use the CNC to do the hard work. The trouble is that the pickguard is about 15mm too wide for the bed of the CNC, so my only recourse is to tile it into two halves, and mill it as two separate sections, with a precise move between the two halves so that they line up. In CAD the pickguard gets split into two pieces and some reference marks added to allow the two halves to be milled separately:

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Then it's off to the CNC with all fingers crossed that the plan works out:

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Succes!. Well...the more astute viewers will note a continuity error between the last two shots, above. It actually took two attempts to complete the pickguard, after I miscalculated how much excess material to remove off the bottom of the sheet and cut it too short. Still, I now have a replacement scratchplate ready to be reinstalled:

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If only my CNC was just that little bit wider...

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1 hour ago, curtisa said:

After loading it in to the CAD software and tracing the edges as best I can and flipping it around, I can then scale it down to match the original, and add an approximation of the missing section behind the bridge pickup. There's probably neater and quicker ways of doing this, but for me this works well enough:

Printing it at 1:1 scale gives me an opportunity to check the fit before cutting up a blank sheet of pickguard material:

awesome work as always Curtisa- but I have a question on what you said here as I am trying to fully understand the process (and I am a complete noob on cad etc)-you said you scanned the original- which would have given you a 1:1 scale (is that correct?)- and the part I am confused on is you said you then "scaled it down" to match the original- perhaps I am just not understanding- but I am taking that as you reduced the size of the scan(?)

I am thinking the scan would have given you a true sized one to one ratio (maybe that is a wrong assumption)- and then loading into cad all you had to do (with the exception of adding the missing portion) is print it and its a match. (so I am not understanding the term scale down here).

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The scan gave me a 600dpi image with dimensions of 9930 x 7020 pixels. In CAD that's pretty meaningless, as dimensions in CAD are unitless. A "thing" that has a length of 100 in CAD could be 100 mm, or 100 inches or 100 feet. It's not until I print it at scale or assign a unit of measurement does it have a real size. I can't remember the exact values, but the trace of the raw image I did was about 3x larger than it needed to be once printed assuming I was using mm as a drawing unit.

I also needed a way to get from an image file (the scan of the pickguard) to a vector drawing (the CAD of the pickguard), as the CNC only uses vectors to drive the cutterhead. By converting to a vector file I can also scale up or down, add or remove components, rotate, straighten, bend etc without sacrificing edge quality and accuracy.

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Looks like you are using QCAD.  I love QCAD - pretty simplified - all the functions needed.  I have done similar methods to scale out a pickguard, like placing a ruler right next to the pickguard, and shooting a photo of it from far away, and as perpendicular as possible, then insert the photo in the "insert bitmap" function, (which allows jpg's a well), then adjusting the scale size until it matches the graduations on the ruler in the pic.    Then I use the spline curve tool to draw all the irregular curves, and basically draw right over the picture.  Then delete the picture, and send it to the laser to cut a test on mylar film, then verify any tweaks needed before I cut my expensive pickguard material.  Usually comes out perfect.    

The scanner is clearly better than my method, but I dont have a scanner large enough normally, or I am too lazy, and like the challenge of making the photo / ruler trick work.    

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You've pretty much nailed how I did it. My only extra trick was that after I scanned the pickguard I reduced the colour depth to two (black/white) and then sent it through the "Trace Bitmap" function built into Inkscape. That gave me a vectorised version of the pickguard edges and cutouts against the black background which I could then use as a basis for the redrawing.

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Rear trem cavity cover gets done with the same pearloid material as the front. No fancy scanning tricks to do this. Just a pair of calipers to get all the key measurements:

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Aye, they're good, reliable little instruments. My first "big boy's" axe was a Pacifica 721. I still regret selling it to fund the purchase of an Ibanez 7 string RG.

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That's good stuff there Andrew--particularly to those of us that have never destroyed a pickup to see how it's made and then put it back together.

SR

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You are lucky with the cable, most mice have unshielded USB 1 cable. Some cables heve very different power wires and data wires, also not good.

Now don't forget to remelt the wax by heating the baseplate gently, otherwise it would squeel badly. No neet to dip the whole pickup in wax though.

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8 hours ago, kmensik said:

You are lucky with the cable, most mice have unshielded USB 1 cable. Some cables heve very different power wires and data wires, also not good.

Shielded 4 conductor cable is part of the USB standard, so it should be there. The cable I've used does have a shield, although it's not a braided type - just a wrapped foil jacket in contact with a bare tinned wire. Stripping the outer sheath of the cable usually takes the foil shielding with it, so it can look unshielded once the wires are exposed.

 

8 hours ago, kmensik said:

Now don't forget to remelt the wax by heating the baseplate gently, otherwise it would squeel badly. No neet to dip the whole pickup in wax though.

I'll keep an eye (ear) out for any issues, but I'm not expecting any problems with microphonics. If I'd removed the tape on the coils and unwound some of the coil, I'd be repotting it. But as all I did was unscrew the coil from the baseplate as a complete unit and didn't disturb the windings, I reckon I'm pretty safe.

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Wrong. The loose mechanical parts - baseplate, magnet, spacers - cause more microphonics than the coil wire itself. Been there. It will come back to you later when you turn the volume up. Even when you tighten the four little screws and everything is firmly reassembled, it might vibrate and squeel at you.

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I've just tested it both ways just to see if there was any difference. Plugged in the humbucker into a high gain amp at an unbearable volume and there was nothing other than the usual hiss, hum and buzz. Removed the pickup from the scratchplate and heated the baseplate with a heat gun enough to make the wax liquefy, let it cool and then reinstalled it into the scratchplate. Plugged in to the amp again and still no squealies or untoward noises.

Maybe I got lucky. Maybe you were unlucky. Who knows?

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Pickguard reassembled and ready to go back in. Note the addition of a treble bypass cap across the volume pot terminals. It looks huge considering it's only 180pF, but it was the only one I had in my parts drawers. Hidden under the scratchplate it won't bother anyone:

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Twenty-something years of dust and crud on the bridge is worth cleaning while the guitar is still in pieces, so strip it all down and submerge the chrome plated parts in shellite for 24 hours. Shellite is roughly equivalent to naptha down here, marketed as a mild solvent, metal cleaner and camping stove fuel that evaporates without leaving behind any oily residue:

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After soaking for 24 hours and scrubbing with an old toothbrush, the bridge is reassembled. A few fingerprints and minor specs here and there still remain, but a damn sight better than it used to be:

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A bit of lemon oil on the fretboard to get rid of the worst of the grime. I was under the impression that these PAC112s were meant to have been sold with bubinga fretboards, but unless they used dye to blacken it, this is the darkest bubinga I've ever seen:

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Bridge back in. It's a shame about some of the scratches and dings that the body has sustained over the years (upper cutaway, for example), but at this stage there's probably not much value in stripping the old finish back and repairing it any further. I believe the body is meant to be basswood with a clear satin finish:, so it'll only dent and scratch again as soon as I look at it:

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All back together again:

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Well done. The scratch could be hidden by some wipe on poly or nitro. I like the natural wood a lot, I believe it is alder.

What screws or bolts have you put in the outer two holes with those metal bushings?

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6 hours ago, ScottR said:

That fretboard says you've played the daylights out of this one....

It saw its fair share of work in its day. It was my backup when I was still gigging, so if I busted a string on my main instrument I'd have it handy waiting to be swapperd over. The guitar was always tuned to drop-D so any song that was in that tuning was just a case of exchanging guitars.

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1 hour ago, kmensik said:

What screws or bolts have you put in the outer two holes with those metal bushings?

What bushings are you referring to?

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