Main Menu
Home Page
About Us
Manuals (service, owners, etc)
Audio Gear & stuff FOR SALE 

Dial Lamp Upgrade Kit

For the JVC RC-M70 boombox

Do you have a JVC bombox?  It's one of the most highly collected boomboxes around, and represents the early '80's so well.  So prevalent and highly recognized is this device that you might say it's even iconic.

In an attempt to spruce up the rather bland tuner dial of this boombox, I devised a kit to make the lamp function actually useful.  The kit is for sale (pricing information at bottom of page).

From this:

To this:

With room lights off

From this:

To this:

The kit:

The switch controller module:

The led lamps + harness:

The project:  From the factory, the original lamps are illuminated when a momentary switch is depressed above the tuner dial.  This illuminates a single incandescent lamp on the right side of the scale.  It is rather dim and lights only so long as the switch remains depressed.  The dial is not lit evenly and the right side far brighter than the left where the light actually dims to almost nothing.  In the dark of night, it serves it's purpose and if you squint hard, you can probably tell where you are tuning but because the meters are not illuminated, it's not really possible to tune with the assistance of the tuning strength meter.  That is late '70's, early '80's technology.

Today, we can do things a little better.   I've devised a 2-part solution.  #1, the incandescent bulb is nixed in favor of a string of ultra bright LED's to illuminate the tuner dial, and some low profile smd LED's for installation above the meter.  The entire LED harness assembly is custom fit for the JVC M70.  It is possible to transfer the same methods here on other boomboxes and I've been working on other possible kits but they aren't ready for sale yet.  #2, I did not like the momentary lamp switch since it takes quite a bit of force to depress.  So I built a switch controller that retains the factory switch so the boombox can retain it's good looks and original feel.  Yet, the actual lamp driving switching function is transferred to this new switch controller module.


(A)  LED's and wiring harness:    For direct replacement of the factory lamps only.  Includes pre-wired LED's with pigtailed wire ends.   Your choice of colors for the tuner dial and meters:  Amber / White / Blue / Green / Red  You can do all one color (as shown) or mix/match the meter and dial.

(B) Controller module: The switching control module.  To allow momentary switches to perform as if they were normal on/off type switches.  The switching action is all solid state controlled.  It has been tested to control up to 4 LED's or the factory incandescent bulb, if that is desired.  Although it is probably OK to control more than the 4 LED's, it has not been tested in that capacity.  This price is for a negative (ground) trigger module but a positive triggered module can be custom built for $5 more.  Includes pigtailed wiring harness. 

(3) The complete deluxe kit:  The kit includes all parts necessary to install onto the M70:  Mounting hardware, switch controller module, power harness with quick disconnect connector, pre-wired LED's with custom fit harness and quick disconnect connector, color installation instructions.

Why do this:  While I hope you do this to increase your enjoyment of your classic boombox and improve it's function and utility, it is also a good way to increase the value of your boombox.  You may have seen this upgrade on boom boxes sold on eBay.  Yes, I created the original one and all others are merely imitations.  In any event, you can expect a several fold return from your original investment by installing this kit.

Installation Requirements:

  • (1) A properly working M70.  If your dial lights are not currently operating, it could be due to a burnt out bulb OR it could be due to a blown or malfunctioning voltage regulator.  The M70 has several voltage regulators and the circuit that powers the dial lamps is also the regulated rail that will power the new LED lamps.  If your regulator is blown, your new lights will not work either.

  • (2) Good mechanical aptitude

  • (3) Basic electronic knowledge and soldering skills

Tools Required:

  • #2 Phillips screw driver, 6" or longer

  • hand or electric drill with 1/8" drill bit

  • 7/32" nut driver

  • T-10 Torx driver

  • Hot melt glue, and hot melt glue gun (recommended)

  • Wire cutters / strippers

  • Soldering iron and solder


Drop me a line for feedback or get information: Norman