Control/Dimming DMX 3CH 4A Decoder - Channel stuck on!

[oddrose]

Hi,

I own a couple of these things

"DMX-3CH-4A 4 Amp 3 Channel LED DMX Controller/Decoder"
DMX-3CH-4A 4 Amp 3 Channel LED DMX Controller/Decoder | DMX Decoders | Controllers & Dimmers | LED Light Strips & Bars | Super Bright LEDs

which I use to control RGB LED strips.

Now, for one of them, the "blue" channel is stuck on 30% all the time, regardless of using DMX or a built-in function to control it.
I have read in other threads on this forum that dimmers have gotten stuck when a Triac is damaged.

Do you think this could be the case here as well?

Thanks for your input!

 

[DavidNorth]

There will not be a TRIAC in this device and instead there is likely either a transistor failure or an issue deeper in the box that drives the transistor. With such a low cost for the box, I would suggest it would be more effecient to buy another one. Does look like a neat device, though.

David

 

[oddrose]

There will not be a TRIAC in this device and instead there is likely either a transistor failure or an issue deeper in the box that drives the transistor. With such a low cost for the box, I would suggest it would be more effecient to buy another one. Does look like a neat device, though.

David

Oh, OK. As you may have notice, I have pretty minor knowledge of the inner workings of this stuff. It is neat though!

If I buy a new one however, I would like to avoid getting the same problem again.
Do you have an idea of what might have caused the problem?

The connections to the LED have all been just wires screwed into the sockets. Is it likely that they have touched and shorted out? Or is it possible that there has been some power overload?

 

[DavidNorth]

It is possible that an issue with the LED circuit caused the failure, but I don't think so. If you are replacing the unit, move the wires for the non-working circuit over to a different output and run it for a couple of days. If that output also fails, then sort out the problem with that LED circuit prior to replacing the box.

Do you have any LEDs in that circuit that are dead? When LEDs fail, they sometimes fail closed and can change the current and voltage on the circuit depending on whether they are wired in series or parallel. I usually suspect wiring, though, as wiring is easy to do, but time consuming to do right and a simple thing such as a single conductor from a frayed wire can be enough to be a problem.

My guess is that this is all just merely a failure within the box that was not created by a load circuit issue as transitors usually do not fail in a partially operating condition.

David

 

[Patchwork1]

I work for an LED lighting company and I see this on a daily basis. We sell those dimmers you speak of as part of our economy line. Like others have stated it's not a triac but a mosfet. These devices do not have short circuit protection and when there is a short circuit condition it will blow the fet. there is nothing you can do to fix it except replace the mosfet. Honestly it's not worth the trouble. I replace the fets on our high end dimmers because they are expensive devices, but these things are a dime a dozen. You have to be careful to make sure you avoid stray strands or any metal bridging the positive and negatives like Dave has mentioned.

On a side note keep your box because the other channels will work fine and you can use them for single color ribbon.

Pat