Utilitech LED light strip

[Welchs101]

Hi,

I have a Utilitech LED light strip go bad. It had some water dropped on it when it was powered up.....anyway, it does not work any longer.

There is not much to this LED strip light..........i think the problem is in the power supply section...ie...where it takes the incoming 125VAC and conditions it before sending it on to the actual LEDs.

I have enclosed pics. Now i can throw this away but i thought i would try and fix it for fun........but i am having trouble figuring out identifying the problem.

Any help would be appreciated.

[ReeceyBurger123]

Re: Utilitech LED light strip

Well you need to clean that corrosion off the bottom of the Psu first that can cause issues.

[Welchs101]

Re: Utilitech LED light strip

yes, i have tried to clean off some of the corrosion.........but this would cause a long term ...right.

[Welchs101]

Re: Utilitech LED light strip

anyone have any thoughts on how to approach figuring out whats not working?

[Behemot]

Re: Utilitech LED light strip

These things are usually very simple. The worst problem is if that tiny 6pin SMD controller went bad - I can read what it is, the other question is if it can be found. But I think these PSUs may be bought of ali or fleebay these days.

Nothing is visually fried there so check the ordinary: fuse, input rectifier, than main switching transistor, capacitors, than move to the SMD diodes and rezistors. If all check fine than most likely it is the PWM controller. These things rarely have any feedback, they are often unregulated (or just by some simple method) so things may blast if something goes wrong.

I played with one of such, the voltage was 80 V open circuit and dropped to 40-60 under load. Than they just hook all the LEDs in series to that thing. Not the greatest method…LEDs are not incandescent lightbulbs, they do not act properly as resistors. That's why it sometimes blasts…or single LED burns and it stops working.

ADD// here you can find one for as low as 3 bucks http://www.ebay.com/itm/1pcs-Constan...IAAOSwgQ9VvDeE

If you won't find the problem quickly just find a replacement which fits, with that price there is no reason to waste time with that.

[Welchs101]

Re: Utilitech LED light strip

wow.........how on earth did you ever find such a thing on ebay. i actually searched the part number on the board and got no where..............huh, pretty cool you found that. i will check a few things like you said..........its just for fun...........thanks!!!!!!!!!!!!!!!

[Behemot]

Re: Utilitech LED light strip

Just search for somethig like T8 LED power supply and check the right one for the lenght and/or number of diodes. I presume they are all just about the same: the number of LEDs is mostly constant and given by lenght (but it may vary so check that), they all have the same voltage drop and they are plugged in groups in series. That means about the same PSU voltage.

So check how many of the LED groups you have and how many are there in series for each group, but I think it will be similar. The diodes usually require much lower voltage than what's their natural voltage drop (about 3 V) to work effectivelly; at that voltage they produce most light but also too much heat.

[Welchs101]

Re: Utilitech LED light strip

hi just curious..........first thanks for pointing out that there are "things" to consider when buying a replacement.......like number of LEDs.....what i am not sure of is ......ok lets say i count the number of LEDs in the long strip.........then what.......i could not find where "number of LEDs" was something to consider when ordering a replacement

[Welchs101]

Re: Utilitech LED light strip

ok, i see after looking closer it says 24 series 4 parallel...........how do i determine this? any ideas?

[Behemot]

Re: Utilitech LED light strip

You can begin by following traces, visually and/or using continuity/diode tester on digital multimeter.

[ben7]

Re: Utilitech LED light strip

Interesting board.

Did it stop working right when water was spilled on it?
If it took a while for it to stop working, my guess would be that one or more of the SMD resistors has corroded. They use a thin layer of metal as the resistive element, which might have corroded away.

-Ben

[Behemot]

Re: Utilitech LED light strip

Shoud not that be inside the resistor package where the water can not reach it??

[ben7]

Re: Utilitech LED light strip

Shoud not that be inside the resistor package where the water can not reach it??

One would think so, but I think if the resistors are poorly manufactured, then it might be a possibility. I just read about this failure mode the other day lol

-Ben