Upgrading a MIM Strat, and then the truss rod broke

Yes, you read it right. The truss rod broke, and it is a huge bummer.

 

I started by removing the old pickguard, electronics, and bridge, and discovered that some of the bridge mounting holes need plugging. One had a plug that came loose, and the other needed a partial plug. My new plug is seen closer to the camera, and the old plug that I reglued is at the sixth screw away from the camera:

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I always shave off the plug with a razor blade. I have two violin carving knives, and they have their use, but the razor blade is real sharp and I can hold it flat against the surface.

The bridge before I cleaned it:

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I took 0000 steel wool to it and it restored its sheen.

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With the new Graphite String Savers saddles:

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Next I roughed in the nut. My friend wanted a brass nut which is the only reason the old one was being replaced. The neck has 9.5″ radius and the nut slot is curved, so I put some 220 grit (or maybe even coarser) between a couple of frets and started sanding down the blank until the bottom matched the radius. I used the old nut to copy the string spacing. I usually plan out and put down the spacing myself, but the old nut had good spacing.

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Next on the bench were the electronics. This guitar was being turned from a standard strat into a two pickup (both are Seymour Duncan Quarter Pounders) guitar with two volumes, on tone, and a 3-way switch. A word on the quarter pounders: they’re not meant to fit into any pickup covers. Also, even if you had covers big enough, they won’t fit into any standard pickguard. I actually called Seymour Duncan to verify that. I took some pictures while I was wiring the thing up.

Ok, maybe just one before and one after. Next I finished the nut and it came out really nice, I think.

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I ended up rounding the corners a bit more after I took this picture. This was my first brass nut and it came out really well. Also, brass is more fun to work with than bone. The files don’t seize like they do with bone, and it’s easier to get a feel as to how much material is removed. It’s harder than bone, but it’s still a soft metal so it’s easy to work with.

Then came the setup and the broken truss rod. By broken truss rod I mean that it broke from the anchor. The nut would go on the rod and down the slot, but at some point it’ll just keep spinning in place. Here are the odd things I noticed about the neck and possible things I did wrong:

– I was fine tuning the nut and action, and needed to straighten the neck. So I tightened the truss rod by 1/4 of a turn, maybe even less and the neck got straighter, as one would expect. But then after maybe 10 minutes the neck was bowed again. This isn’t normal really, and I didn’t think much of it. Also, I kept changing the action at the bridge, and the strings go tuned to pitch and de-tuned, so I figured it’s within the realm of possibilities that the neck would be bowed again, even though I’ve never seen that before. This thing repeated itself maybe two or three more times: Tighten the rod, everything seems straight, then a few minutes later the neck is bowed again. This should have been the first warning sign. It’s not normal for a neck to get bowed after ten minutes, and definitely not normal if it happens several times.

– I removed the truss rod nut to see if anything was wrong with the threasd (and also lubricate it). Screwing it back on the rod was a struggle. Because the rod is adjusted from the headstock, it is a real pain to get the nut to thread on the rod. I actually used force to get it to catch on the rod. That probably didn’t help the truss rod.

– I kept tightening the rod under string tension. With healthy rod that’s not a problem, and I pretty much always tighten the rod under string tension and it’s never been a problem (but could be one with 12 strings). Usually the guitar “lets” me know if I need to detune the strings to tighten the rod – it’ll just resist more.

I took the guitar to a luthier in town for a second opinion. I never worked with him, but I’m always impressed with his work when I see it. He pointed out a few things. The first was that with the strings slack and the truss rod not functional, the neck was really bowed (concave, like too much relief), and it should actually be straight. If it has no string tension and it’s concave, imagine how much more it’ll be with strings on, and how much work you’ll ask the truss rod to do to resist that. That’s what I witnessed, essentially. I was tightening the rod and it wasn’t making the neck straight. The second thing he pointed out was that the truss rod might have been shot, or was going to break soon anyway.

The more I think about it, I think the truss rod was boinked already. I’ve adjusted a lot truss rods at this point. I know what it feels like when they reach their limit. It’s like when you turn a bottle cap, it gets gradually harder to turn, right? This wasn’t really happening with this guitar, even before I took off the nut! The resistance from the nut was constant.

However, since I take pride in what I do, I took full responsibility over what happened and I’m now looking for a new replacement neck.

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Studer B67 recap: Part VIII

I just cleaned and recapped the counter board. The underside was filthy, so I thought maybe something got short because of the dirt.

I reinstalled it in the machine (after I finished putting the new caps in), turned it on, and it still remains that only one motor is responsive, but also the problem where spinning the roller causes the supply to stop working is back – but with the take up! So the take up is still responsive 80% of the power ons, but now if I spin the right hand roller by hand, that causes the take up to stop running and the supply to start spinning. When the supply is responsive, spinning the roller doesn’t make it stop. Huh.

Going to replace that chip now.

I haven’t updated in a while!

Here’s what was going on. First, I’m a little busy studying, so that takes priority over the Studer (and all other projects for that matter). I also started re-arranging my work space, so now there’s more storage and hopefully less clutter when I’m done, but that made my desk even fuller for a few days. Lastly, and most interesting is that my friend and I narrowed down the problem.

I looked at the block diagram (p. 240 of the PDF manual) and noticed that signal from the right sensor board goes to the pre-divider, and since part of the problem is that spinning the right roller causes the supply motor to stop running, I figured I’d look around the pre-divider board. My friend suggested I replace IC3 on the counter board, and also to try replacing all the ICs on the pre-divider. I did replace all the ICs on the pre-divider, and that solved the smaller part of the problem – spinning the roller by hand causes the supply motor to stop working. However, I don’t know which IC did it.

Today I’m going to recap the counter board and change that IC and see what happens. I hope that will be it. Voltages of everything everywhere test fine, so the counter seems to be the last stop.

Also contributing to the delay was that I had to order new ICs, and by accident some of the ICs I bought were SMD, so I had to get new ones.