Yamaha TRBX174 Bass Needs Some Help | Part 1

Part 2 ▶

1 Introduction

This Yamaha TRBX174 four-string bass is in the shop for servicing, a string change and setup. I've noticed a few areas of concern thus far, and will be highlighting them later. For now, however, let's peruse a number of specs sourced from the World Wide Web; and my own observations.

1.1 Identification

Origin: Indonesia

Serial Number: IQY113482

Neck Pocket Stamp: October 26, 2020

1.2 Body Specs

Body Shape: TRBX

Body Material: Alder

Body Finish: Gloss Polyurethane, Black

1.3 Neck Specs

Neck Construction: Bolt-On

Neck Material: Maple, Flat Sawn

Neck Finish: Satin Polyurethane, Clear

Truss Rod Adjustment: Heel End

1.4 Fretboard Specs

Fretboard Material: Sonokeling

Scale Length: 34"

Fretboard Radius: 10"

Frets: 24, Medium

Fretboard Inlays: Pearloid Dot

Side Dots: White

1.5 Hardware Specs

Hardware Finish: Chrome

Tuners: Die-Cast, Covered

Nut Material: Urea

Nut Width: 1.57"

Bridge: Vintage-Style, Barrel Saddles

Jack Plate: Plastic, Black

Control Knobs: Plastic, Ribbed, Black

Control Cavity Cover: Plastic, Black   

1.6 Electronics Specs

Pickup Configuration: P/J

Neck Pickup: Ceramic Precision-Style Split-Coil

Bridge Pickup: Ceramic Jazz-Style Single-Coil

Control Configuration: Volume/Volume/Tone

Volume and Tone Pots: Alpha, 250K

Tone Capacitor: Polyester Film, 0.047uF

Output Jack: Mono, Open Frame

2 Alder Body

Now that we've seen some specs, let's get down to the nitty-gritty. Up first is the rather dusty body. Topside, we see the truss rod access channel, pickups, bridge, control knobs, and two strap buttons. Removing the neck reveals the neck pocket, stamped with "26 Oct 2020." Now, looking real close, one can see that the body wood is indeed alder, and not basswood as I'd guessed. Flipping the body over, we see the bolt-on joint, four-screw chrome neck plate, black plastic control cavity cover, and yes, those strap buttons.

Body - Front View

Truss Rod Access Channel

Vintage-Style Bridge

Neck Pocket and Truss Rod Access Channel

Body - Back View

3 Maple Neck

What's next? Well, it's the back of the headstock. There's lots of interesting things going on here, and I'm not talking about the tuners. What's caught my attention, besides the "TRBX174" sticker and stamped serial number, is the black Yamaha "CE EAC" sticker. A bit of Googling reveals that "CE EAC" means this bass meets both European and Eurasian Economic Union "safety, health, and environmental standards." As for the Russian text, the first line reads "Electric Guitar," and the second; "Made in Indonesia."

Back of Headstock

TRBX174 Sticker

Stamped Serial Number

Yamaha CE EAC Sticker

Now we're looking at the back of the bolt-on maple neck itself. The wood is lightly figured, and finished in clear, if not lightly tinted, satin polyurethane. It feels nice and silky, quite unlike those predominantly sticky gloss-finished necks. One thing I've noticed about the neck is that it's actually slanted upwards in relation to the body, leading to unnecessarily high action. We'll definitely have to correct that. And as mentioned in an earlier paragraph, truss rod access is at the heel of the neck. Speaking of which, the grain pattern at this end indicates that this neck is flat sawn.

Satin-Finished Maple Neck

Right Side of Bolt-On Joint

Left Side of Bolt-On Joint

Neck is Slanted Upwards

Neck Heel Markings

Truss Rod Adjustment Socket

4 Sonokeling Fretboard

Yes, folks, I can hear the other side of the neck calling for attention. Right, the headstock face gets first dibs. Nothing fancy here, just a black satin finish, the Yamaha logo, and a chrome string retainer bar. Moving down, we have an unbound sonokeling fretboard with a well-seated white urea nut, 24 medium frets, pearloid dot inlays, and white side dots. Of particular interest are the neatly sealed fret slot ends, which contribute towards a clean and smooth-feeling fretboard edge.

Headstock Face

Urea Nut - Left Side

Urea Nut - Right Side

Two-Octave Sonokeling Fretboard

Pearloid Dot Inlays

White Side Dots

Sealed Fret Slot Ends

5 Electronics  

Electronics-wise, there's nothing really worth writing home about, so to speak. Relatedly, I've been given the assurance that they're all in perfect working condition, so there you go. However, for the purposes of this post, the control cavity cover and output jack plate have been unscrewed to reveal the innards. And, out of a sense of duty, I've serviced the pots and jack with contact cleaner. Pot values have also been measured, and they range from 220K to 270K. Tolerances and all that, one might say.

Control Cavity Electronics

Alpha 250K Neck Volume Pot

Alpha 250K Bridge Volume Pot

Alpha 250K Tone Pot

0.047uF Tone Capacitor

Output Jack and Jack Plate

6 Hardware Issues

At this point in time, the control cavity cover and output jack plate have been reinstalled, and this might just be it as far as the electronics are concerned. Shifting focus to hardware components, it must be said that most everything is tarnished and in need of servicing. And so, it has come to pass that the only visible appointments remaining on this Yamaha TRBX174 bass are the tuner bushings and pickups, everything else having been disassembled. Now, where's that tube of Autosol?

Hardware Disassembled for Servicing

Undersides of Neck Plate and Bridge

What's Beneath the Neck Plate

What's Beneath the Bridge