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Topic: What is this LED driver/stepup/stepdown (Read 1 time) previous topic - next topic

jointtech

A friend of mine has a strip of LEDs, a ribbon in a limo.  The lights quit working.  He pulled this box out.  It looks like it is toast. 

Any ideas what it is/does?  I was under the impression a lot of LEDs use 24volt so this may be a step up device from 12v?

The red and black go to power and ground.  Both whites go to the LED ribbon. 




CrossRoads

Why is there so much crap around what look like regulator pins? Clean that up, see if it helps.
Slide the heatsink off that part, see if there is a part number.
If anything, I would say this is an AC to DC converter with full  bridge rectifier and linear regulator, with the white wires as inputs and the black & red as outputs.
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

jointtech

my bad attempt at desoldering it...
:smiley-roll:

The heat thing is pretty stuck on there.  Ill try again to pull it of.

jointtech


jointtech

looks like its this guy
http://www.fairchildsemi.com/ds/MJ/MJE181.pdf
  wait what...  low power audio amplifier?

Chagrin

The transformer / non-polarized (white) wires suggest it was powered with AC current. You claim that the white wires connected to the LEDs, but that would force the installer to test and potentially flip polarity during assembly since LEDs certainly care which side is positive and negative. Are you insistent that the white wires connected to the LED ribbon?

Zapro

That board looks exactly like the internals of a small Wall Wart with voltage regulator.

It gets AC line current on the white wires, and the red & black is the regulated DC out. This will _never_ work in a car, unless it was powered from a AC inverter, making mains voltage.

Also, the solder job on the transistor (rigged as voltage regulator by the two resistors) looks bad.

Are you sure that your friend isn't pulling your leg ?!

This has nothing to do in a car.

// Per

Paul__B

I would be presuming it is a DC to AC converter driving not LED strips, but an electroluminescent ribbon.

Zapro


I would be presuming it is a DC to AC converter driving not LED strips, but an electroluminescent ribbon.


Under further scrutinizing i would have to agree on that, that makes perfectly sense - it's just the four diodes that threw me off.

Yep, looks like an inverter for EL-wire.

// Per.

jointtech

hi guys. sorry for the late response.  For some reason I got notified on the first reply but not again...

crappy soldering - thats me trying to desolder the burnt up part.  I did a crap job and didnt finish because I decided to just buy a new unit.  Unfortunately I still cant figure out wth it does and what to replace.

2 whites definitely plugged into the LEDs.
Black and red went to 12V in the car.

there is no inverter in the car. 

Just for giggles I'll have him voltage test the red and black but Im pretty sure I had him do that already and it was 12v (or close)

It looks like that part is only a couple bucks so I may just try to desolder and replace it and see what happens.

Update:  The car did have an inverter at some point.  but not since he has had it and the lights have worked since.
He did hook a test light to black and red in the car.  The light lit up.  But I'm making him go put a volt meter on it to verify theres not some invertor hidden somewhere else.

jointtech

#10
Dec 12, 2013, 09:42 pm Last Edit: Dec 12, 2013, 09:51 pm by jointtech Reason: 1
Quote
electroluminescent ribbon.


Exactly!!!   i thought those were just little LEDs but this sounds more likely.

update:  just talked to him.  it is the ribbon.  would have been nice if he said that to begin with.

Now to figure out which driver will work for about 12 feet of ribbon.

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