Anyone familiar with this (cheap) aftermarket speedo? Need help replacing backlight

[Guest]

So one of the very minor (but also very annoying) issues with my newly-acquired 81 GS1100E is that the backlight on the speedometer does not work. The analog gauge itself works and is fairly accurate, and the small colored LED idiot lights (oil press, neutral indicator, high beam indicator, turn signals) all work just fine, its just the illumination/backlight for the gauge itself that is dead. In my experience, especially on cheaper gauges like this, the backlight is a simple incandescent bulb that inserts into the rear of the housing/backshell. Or sometimes you have to remove the backshell to get access to the bulb inside. However on this one, the bulb is not accessible from the rear, and the housing seems sealed. I removed all the fasteners on the back, but the bezel around the gauge face seems sealed (glued? welded? press fit?) to the backshell, and the two won't separate. The gauge looks to be a generic chinese-made unit, no branding, model#, or markings of any kind. It is IDENTICAL in every way to a model currently sold by 4into1, though I suspect they are just distributors and it can likely be found elsewhere under a different name. 4into1 states the following on their website, so I'm not expecting much help from them: "We do not offer product technical support, phone services or help with installation".

https://4into1.com/mini-speedometer-w-indicator-lights-trip-meter-2240-60-black-mph/

https://www.amazon.com/gp/product/B07YMTRZZY/ref=ox_sc_act_title_1?smid=A3FU5TBQS82L5W&psc=1

So I suspect that either the backlight inside the gauge is an LED (would be a little surprising for such a cheap gauge?) that was assumed to last the life of the gauge and as such there is no way to replace it. Or it IS an incandescent bulb inside, but the gauge is so cheap there were no provisions made to make the bulb serviceable? Before I write off this gauge and proceed to more aggressive (potentially destructive) disassembly methods I figured I'd reach out to the experts here to see if anyone else had experience with this gauge model and knew of a "trick" to get the backlight replaced. If not, time to bust out the heat guns and pliers (and get a backup replacement gauge on order ) and see if what there is to see.

If there is a better forum to post this, please let me know. Electrical seemed the closest to my issue.

[fastbysuzuki]

In the one review they state the back light is l.e.d and I would suspect that is the case given how cheap they are to manufacturer.

[Guest]

In the one review they state the back light is l.e.d and I would suspect that is the case given how cheap they are to manufacturer.

AH thanks, I missed that comment/review! If its LED then I will give up now. Funny, in my mind an LED backlight is the new fancy option for higher end gauges, and the ole incandescent bulb and socket is the cheap budget option. But if I stop to think about it obviously that's not the case any more You'd probably have to pay more these days for a "retro" style analog gauge with authentic flickering orange incandescent bulb effect

[Agemax]

did the backlight never work, or did for a while then packed up? if it never worked, try swapping the + and - wires, you never know they may have accidentaly wired the led up back to front during assembly.

[Gorminrider]

Check your connections. These are them for my very very similar piece of junk.
Grounding/Negative wire: Black line
Backlight wire: Red line
Turning light Wire: Yellow line
Headlight wire: Blue line
Neutral wire: Green Line

[Guest]

I checked all the electrical connections and everything on that front is good. I only got the bike a few weeks ago, backlight has not worked since I got it. No idea if it ever did? But like i said, it is wired correctly and the ground has a good ground, etc etc.

[Who Dat?]

It's entirely possible that 4-into-1 speedos are supplied by Lucas.

Remember, the Lucas motto was "Be home before dark".

[LAB3]

It seems that you're assuming the LED light isn't replaceable, it could well be that it plugs or screws in like an old incandescent. You'll never know if you don't open it up and if you've already resigned yourself to buying a new one, what do you have to lose?

[Guest]

It seems that you're assuming the LED light isn't replaceable, it could well be that it plugs or screws in like an old incandescent. You'll never know if you don't open it up and if you've already resigned yourself to buying a new one, what do you have to lose?

Oh for sure, and just out of curiosity I'm sure ill pry this one apart to see what happened in there. But if the backlight is LED, its 99% chance the thing is unrepairable, or at least the effort to do so would be all out of proportion. If it's LED, I suspect its in an SMD package/form-factor, as those are orders of magnitude more economical than the older DIP package style, much less some sort of replaceable unit with a socket or connector. And considering the unit is sealed solid (confirmed the bezel and backshell are sealed with some sort of brazing/adhesive) it seems unlikely they'd pay more to make the lighting element serviceable. And even if if were an SMD (or DIP) emitter, I could easily de-solder and replace if I wanted, but the odd's are the problem isn't with the LED itself. Unlike incandescent bulbs, the actual LED itself is very robust, usually much more so than the rest of the circuit. So if there are problems its usually a shorted/corroded trace on a circuit board, funky power supply, etc, not the LED itself. And even THEN I could probably repair a trace or take it into the lab and have a replacement board made up. But at that point, how much of my time am I wasting over a $70 speedo? Like I said I'm sure I'll pry the thing apart at some point out of curiosity. My work-brain wont let me have a piece of failed electronics on my bench without getting to root cause

[LAB3]

Oh for sure, and just out of curiosity I'm sure ill pry this one apart to see what happened in there. But if the backlight is LED, its 99% chance the thing is unrepairable, or at least the effort to do so would be all out of proportion. If it's LED, I suspect its in an SMD package/form-factor, as those are orders of magnitude more economical than the older DIP package style, much less some sort of replaceable unit with a socket or connector. And considering the unit is sealed solid (confirmed the bezel and backshell are sealed with some sort of brazing/adhesive) it seems unlikely they'd pay more to make the lighting element serviceable. And even if if were an SMD (or DIP) emitter, I could easily de-solder and replace if I wanted, but the odd's are the problem isn't with the LED itself. Unlike incandescent bulbs, the actual LED itself is very robust, usually much more so than the rest of the circuit. So if there are problems its usually a shorted/corroded trace on a circuit board, funky power supply, etc, not the LED itself. And even THEN I could probably repair a trace or take it into the lab and have a replacement board made up. But at that point, how much of my time am I wasting over a $70 speedo? Like I said I'm sure I'll pry the thing apart at some point out of curiosity. My work-brain wont let me have a piece of failed electronics on my bench without getting to root cause

Well back in my day all we had to do was open it up and see which vacuum tubes weren't glowing! And we did it in 20 degree below weather for 100 miles up hill in both directions! At that price point it could well be that Bubba Ching Chong found a left over lot of NOS knockoff innards, you never now.

[Guest]

Well back in my day all we had to do was open it up and see which vacuum tubes weren't glowing!

heheheh. one of my first assingments at my current employer was to track down a balanced set of these:


Big 480V power triacs in motor controller for our centrifuge This was only around 2010 or so... but the centrifuge was built in '57 I think

[LAB3]

heheheh. one of my first assingments at my current employer was to track down a balanced set of these:
Big 480V power triacs in motor controller for our centrifuge This was only around 2010 or so... but the centrifuge was built in '57 I think

My schooling was in the late 70's, kinda on the digital/analog cusp. The older guys where intimidated by those newfangled chips and the younger guys saw analog as coal and steam technology.

[Guest]

My schooling was in the late 70's, kinda on the digital/analog cusp. The older guys where intimidated by those newfangled chips and the younger guys saw analog as coal and steam technology.

Whenever I would give tours of our test lab, I'd always point out the 60yr old centrifuge with vacuum tubes. being a bit of an anachronism next to the bleeding-edge vibe cells and TVAC chambers and such. You could predict the response to the vacuum tubes by the age of the group of visitors (from nostalgia to "huh?"). Regardless, everyone giggles like a schoolgirl when you fire em up and they purple blobs of plasma start glowing and sputtering and pulsing as the motor comes up to speed. It's all a lot more dramatic than a bunch of transistors, I'll give ya that!

[wymple]

did the backlight never work, or did for a while then packed up? if it never worked, try swapping the + and - wires, you never know they may have accidentaly wired the led up back to front during assembly.

I bought some LEDs from the auto parts store for turn signal indicators on a custom project, and the would only work electrically wired in one direction. I understand that all LEDs are not this way, but I would cross the wires to see.

[Gorminrider]

On mine, I don't recall anything easily replaceable but you can get tiny discrete LEDs from ebay ... There are 12volt ones available and they are very bright. ...