LED tube from an auto kit work on molex?

[releasedtruth]

Well, I came across these 2 led tubes, 9" long, they had a cigarette adapter on them, but say to cut it off if it's not for the car, so I do. I wire it to the 12v and ground on my computer power supply and it sparks and shuts the comp down. I have my other leds running off a power supply fine so what's up? I know I have the right wires, etc. They ran off the car 12v fine so?

Thanks, GT

[NickG]

Are you sure they are LED and not CCFL?  CCFL requires the inverter and the inverter may have been built in to the adapter, eh?  If they are indeed LED then what kind of current regulation have you implemented for the light elements?  If they are CCFL, is the inverter in circuit?

[BobA]

Take a look inside the the cigarette adapters that you cut off.   Most likely the resistors are inside the adapters.   If you do not have the resistor in the circuit the LED will burn out.

[Kevin Mullins]

Maybe the fact that you're talking about DC voltage.... maybe you had the polarity reversed.  +  -    (even LED's have polarity on them)

[releasedtruth]

I was told the resistors were in the tube itself rather than the car adaptor, but that's the first place I'm going to look. I'm positive they're LED though. The box made the suggestion to cut off the adapter if it wasn't for car use so I did. I rewired it to make sure the tubes are still functional and yeah, still good in the car.  I made sure that the + went to the yellow 12v on the molex and the - to the black wire.  I figured it would be like my other leds I wired up for my cabinet buttons, but not thus far.

[fredster]

You have it wired right. But it might be taking too much power from that P/S.

Do you have another power supply in a dead computer you can use?  Read the voltages off it with a multimeter.  LED's won't work backwards. That's the nature of them.

A stupid option is to just get a lighter assembly and hook it up to the P/S then try it with the adapter in place.

[BobA]

Check your wiring too.   Reversed connections will not let current flow so if simply reversed nothing would happen.  Sparking or shutdown indicates an overload from bad wiring or no load limiting resistors ( the LEDs would probably burn out first if this was the case)

BobA

[releasedtruth]

I tracked the model down online. These ebay folks are selling the exact thing. I didn't find resistors in the adapter. I know I have the wiring right, at least as far as I've wired a few hundred single leds together before. The sparks are new though 

eBay Link

[NightGod]

Have you just tried hooking the power from the molex directly up to the cigarette adapter? Not as pretty, but it's going to be inside of a cabinet, so who really cares?

[ChadTower]

Those things should be consuming very little current.  I would suspect that either his wiring is wrong or there is some type of short in what he connected, especially given that the tube tests well in another setup.

He probably shorted something out in his wiring hack, which connected +12v directly to ground, and caused the overload and shut down.

[leapinlew]

Those things should be consuming very little current.  I would suspect that either his wiring is wrong or there is some type of short in what he connected, especially given that the tube tests well in another setup.

He probably shorted something out in his wiring hack, which connected +12v directly to ground, and caused the overload and shut down.

I concur with Chads theory here

[releasedtruth]

I have some other leds running off the same power supply on another molex connector. Would that affect anything? They're specifically designed for that purpose though so I'm not sure. I tried them again in the cigarette lighter, still good. I just can't imagine that my wiring is wrong. Pos to yellow, neg to black, right? I'll try another molex, see if that changes anything.

[NightGod]

Did you try connecting it up while the cigarette adapter is still in place? Just to see if its a problem with the adapter being out of the loop or your power supply?

[ChadTower]

It's worth trying.  There could be some surface mount resistors in there he doesn't recognize.

[releasedtruth]

Bingo gentlemen!  I reattached the adapter, then soldered wires to the adapter, it works. Ugly and fragile, but functioning. No one will see it anyway...  Thanks for all the responses, helped get me back on track!

GT

[NightGod]

I'd now suggest adding a big glob of hot glue to take care of the "fragile" part of that equation. It will add to the ugly, but I'd rather have a hidden part look hideous and never fail.

[RayB]

Why is this in Arcade?

By the way, you inspired me to add ground lighting to my MAME cab...

[quarterback]

you inspired me to add ground lighting to my MAME cab...

[releasedtruth]

Since my control panel is open on the underside, the light will shine down underneath giving off an excellent blue glow to match the blue illuminated buttons and such. Should be slick

[RayB]

What's the most I should pay for a "stick" style light?

[releasedtruth]

I think I paid 11 a piece for 9" lights. The 12" I think were around 15. Probably not the cheapest, but pretty complete setup

[quarterback]

What's the most I should pay for a "stick" style light?

I got mine for ~$5 per 15" 'stick', but it was a clearance deal.  When I bought them, I didn't even know what I was going to do with them and was about 3 years before I got my 1st cab, but once I started on this route, I quickly decided I'd use them somehow.

They don't fit the theme of my upright, so when I got the cocktail and decided to go with lighted leafs, the light-sticks were instantly on my build-list.  The only downside is that they're a little thicker than the amount of space available under my cocktail.  It's fine when it's on the carpet, because they just sink in, but I'm a little worried about their longevity and whether or not I'm going to actually break them.   Right now my cocktail is still being moved about (and de/re-constructed) so they're not attached to the bottom.  We'll see what I finally decide to do with them.

If you've got the time and want to save a few bucks, you should check out your local auto-parts stores and just price them out.  There's a place up the street for me that puts stuff in a clearance bin all the time for cheap cheap cheap.  I've gotten some cool stuff there and 'lighting mods' are frequently in the bin.  I got some cool dragon heads and cobras with light up LED eyes as well.