CA Guitar Repair Blog: 2006 Yamaha RGX121Z

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Initial Assessment

What we have here is a gloss black Indonesian-made Yamaha RGX121Z. One may describe this guitar as being an HSH tremolo-equipped S-Style with no pickguard. It's a 2006 model, based on the "QMJ163052" serial number. While there are a number of issues that need to be dealt with, I'm constrained by the owner's instructions to "reuse the existing hardware" and replace a component only if "it's absolutely necessary." Fair enough, methinks. As the owner is a family man, I'm sure he needs to watch his pennies.

Model Label/Serial Number Stamp

Tremolo Claw and Springs

On the whole, the tremolo claw is tarnished, grimy and rusty. You can also see that the black ground wire has been hastily resoldered. I'll definitely have to desolder this connection and start from scratch. The most corroded areas of the claw are to be found directly above and below the ground tab. Flipping the claw over, it's evident that metal has been "eaten" away, leaving a sizeable hole. The three springs, meanwhile, are equally rusty and there's hardly any shine on the chrome. We'll have to see just how deep the corrosion goes. On the bright side, the two mounting screws are in much better condition than the claw or springs. They should be as good as new after a little cleaning and a lube job.

Corroded and Grimy Tremolo Claw

Tremolo Claw - Underside

Corroded Tremolo Springs

Screws Are in Better Condition

Tremolo Bridge

The vintage-style tremolo bridge is painted black, just like the rest of the hardware on this RGX121Z. The base plate is attached to the body via six mounting screws, all of which are covered in crud, rust and grime. The saddles, intonation screws, springs and height adjustment hex screws are in slightly better condition, albeit missing black paint in numerous spots. On the underside, one can see that the zinc tremolo block is encrusted with "barnacles," for want of a better description. There's also loads of dust, cobwebs and even small wood shavings all over the place. Cleaning all this up is going to be one heck of a job, I tell you.

Rusty Bridge Mounting Screws

Zinc Tremolo Block

Neck and Bridge Humbuckers

The neck and bridge humbuckers are in working condition. They are mounted in black plastic pickup rings, with black mounting and height adjustment screws. What's really interesting about the humbuckers is that they're totally identical. Both humbuckers have an etched "F" on their brass base plates, similar cabling, and even DCR value. My guess is that the "F" stands for "Front," and both these pickups are actually neck humbuckers. Proof of this is that the bridge humbucker has to be installed "upside down," with the cable exiting from the top; to get the screw coil to face the bridge. And, as expected, both pickups suffer from tarnish, rust, grime, cobwebs, and once again; wood shavings. Note that in the images below, no distinction has been made between the neck and bridge humbuckers; as they're identical.

Humbucker - Underside

Humbucker - Left Side

Humbucker - Right Side

Humbucker - Rusty Spring

Humbucker - Assorted Gunk

Middle Single-Coil

The middle single-coil is also in working condition. However, unlike its neck and bridge counterparts, it is not mounted in a black plastic ring. Instead, it's mounted directly to the body with two black mounting/height adjustment screws, and chrome springs. No, this is not an Alnico V, based on the spotted ceramic bar magnet glued to the bottom of the pickup. Other noticeable features on this pickup include rusty screws and springs, the black coaxial lead; and abundance of dust, grime and cobwebs.

Middle Pickup - Top

Middle Pickup - Underside

Electronics

We shall begin with the black dome knobs, pot shafts, nuts and washers; and also the output jack, nut, washer, and black plastic jack plate. Although the metal knobs and jack plate should not, strictly speaking, be categorized as electronic components; I'm doing so for the sake of continuity. Ok then, the dome knobs first. These feature set screws and are meant to be installed only on pots with SOLID shafts, such as those on vintage Telecasters and Precision basses. Installing them on knurled SPLIT shaft pots will either damage the split shafts or cause them to collapse inwards. You can see in the second image below how the set screw has already damaged the volume pot shaft. Do also take note of the rusty nut and totally corroded washer.

Dome Knobs with Set Screws

Damaged Volume Pot Shaft

Moving on to the underside of the black plastic jack plate, one notices how grimy and tarnished the output jack is. Equally unsettling is the gnarly exposed section of ground wire and solder joint. Once disassembled, the full extent of corrosion is clearly visible. Rust has set into the cylindrical sleeve [ground] of the output jack as well as the lock washer. There is also a ring of dirt embedded around the hole in the jack plate, which is most probably rust. It certainly looks like we'll have to thoroughly clean the jack plate and install a new output jack.

Jack Plate - Underside

Corroded Sleeve and Washer

Let's take a look inside the control cavity now. The whole cavity is unshielded and shall remain so, no thanks to budget constraints. Control cavity components have been disassembled for closer inspection. I'll start off with the five-way blade pickup selector switch [first image]. This plastic-bodied switch is actually of a higher quality than the "metal box" PCB switches commonly installed in Asian guitars. Also visible is a free-standing 0.047uF poly cap, which most probably got detached from the tone pot. Moving in closer [second image], take note of the gnarly soldering job, burnt insulation, and discolored switch body. Someone's definitely been in here with a soldering iron and made a mess of things.

Detached Cap/Pickup Selector Switch

Gnarly Solder Joints

On to the mini pots, then. The volume pot, besides suffering from a damaged shaft, is also riddled with corrosion and traces of salt. You'll also notice the grimy wiring, the exposed sections of which are badly tarnished. There is no way we'll be reusing any of this. The tone pot is in slightly better shape, but isn't getting a clean bill of health. Burnt insulation, messy blobs of solder, exposed wiring and missing tone cap all indicate a botched wiring job. This pot will also be replaced, of that you can be sure. Well, folks, that's about it for this post. Thanks for dropping by.