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One channel on controller does not fully dim


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Hello, I recently picked up a 5+ year old new-to-me CTB16 controller, and one of the channels does not fully turn off when I was testing it with a single strand of LED lights.  All the other channels are fine. I would say the problematic channel is at about 10-20% when it should be fully off, so while not super bright, it is definitely noticeable. I tried doing the jumper reset of the controller, but that did not solve the problem. I then tried having two sets of lights on this channel, and it made a bit of an improvement, so I plugged in an miscellaneous AC adapter into the lights and that completely took care of the problem.

While I could just keep plugging stuff into the end of the lights, does anyone have an idea as to (A) what is causing this issue, (B) will it get worse over time if I just ignore it, and (C) what is the appropriate solution to this issue?


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Three possibilities.

#1. The L.E.D. strand may not be wired the same as the others.  If you take out the plug of the strand from the controller and rotate it 180 degrees, so that the male plug is inserted with the prongs opposite from their original position may/may not fix this.  I had one strand, all purchased at the same time and all identical in brand, but one strand stayed lit 10-20% as your is doing, I just flipped the male plug and that resolved the issue. 

#2. Just add a C7 light bulb {or a snubber} at the end of the L.E.D. strand that is causing the issue, this may/may not resolve ths issue.

#3. This is the most difficult, the Triac on that channel has gone or is going bad, you would have to take the controller completely apart and unsolder the old triac and replace with a new one.  You will also need to know which CTB16PC you have as each one uses different triacs.  Once you know, just submit a help desk ticket to LOR, they are usually pretty good at sending you out some replacements at no charge.   Or you could send the unit to LOR and have them locate and fix the issue, if it turns out the Triac is the problem, it's doubtful it may be anything else, but you never know.   But you would have to pay for the repair and shipping to them, not sure about if you also pay the shipping fees to get it back.

Just a couple of suggestions on how to handle the current issue and what could be the causes.

Good Luck.


Edited by Orville
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Thanks for the suggestions, I'll try the plug flipping idea, and if that doesn't work, adding of extra lights/bulbs will hopefully be a good temporary fix. I might try tackling a triac repair after the Christmas season just in case I end up messing up the whole board.


Thanks again.

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