Bad Triacs

[joshuashu]

Any one else having trouble with triacs going bad? I have 4 this year, with nothing running but LED and one strand at that?  Is the extreme cold having some thing to do with it? I know i heard something about it over at PC, but since the CS will not let me post i can not search? any ideas or options?

[Rainlover]

I have had 3 stick on. Since I am a newbie, I am guessing that my problem has more to do with bad soldering than bad weather. We have not had any real cold weather, just a lot of rain. Before I put the controllers away, I will check the solder joints and fix or replace.

John

[trekster]

I have 8 LE's and 4 SSR4 DMX running without any problems.  They are all from 2010 coops as this is my first year.  I have not had any "stuck" triacs or any problems with the controllers.   I did have the GFI pop every night on the mini trees.  I was told that the wire tomato cages would do that.  I just plugged that controller into a non GFI and it has not gave me any more problems.  We have not had much of any cold weather though. 

Ron

Oklahoma

[jnealand]

I have had to replace 3 triacs so far this year.  I have one more that appears to be shot, but I have spare channels on that controller and will look at that one in more detail after the season is over.

[blickensderfer]

Two nights ago I had one triac to bad.  So far this is the only one out of 7 expresses.

Dan

[kylec]

I've had about 300 triacs in use for the last three years and haven't has to replace one yet.

Kyle

[lortiz]

There is a thread going on over at DIYC about users experiencing issues with triacs from STMicroelectronics.

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Leo

[RJ]

That is not the normal triac for the Express. But I did have to use some once as a sub to finish a coop. So there may be some in use in expresses. Be funny to see if the couple people that posted they had failures (other than the shorting it out that always kills them   ) if these were the model there having problems with. we might be able to support them in their case if we can show our setup has failures when using them but not when using the normal unit. They can't say that as they use that model as the norm. We have had very low failures over the year. I know I bleieve I see more and more but I know I have many many more out in use also so this can throw your perception.

RJ

[Dennis Cherry]

Remembered that post about those triacs.

Just looked at the one that failed last night, it has a big "ST" on the triac.

Also all the triacs I bought from Mouser this month have the "ST" also.

Do I win the prize?  

Just attached a photo for you to see

[wbuehler]

I have had one bad one in the past 3 years.

Bill

[ThaiWay]

The only bad ones I've had are because of my fault.

[crazybob]

I had one go bad this year too. I don't think it was the LE's fault, nor do i believe it was mine. I was using banks of floodlights in outdoor light stakes pointing straight up under the house, and rain got in. I called the company that makes the holders, and they told me that they can NOT be used pointing straight up, or they won't be waterproof (even though it said this no where in the instructions).
Luckly I had some spare channels. I'm assuming this can be fixed after the season? Since a bunch of us seem to be having this problem, can someone post instructions on the easiest way to unsolder and replace a triac?

[wbuehler]

I would suggest one of these, I have one and it works great from removing components.
You can get them from Radio Shack.

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[RJ]

The safest way to replace them with the least risk to the pcb is this:

1 - Unscrew the triac form the heatsink.
2 - using a pair of needlenose pliers grab the tab on top and bend the triac over towards the screw terminals away form the heat sink. Then bend it back up straight. Repeat until the legs breadk and you can take it away.

3 - now using a solder sucker like bill posted heat one pad and let it get real hot. Now donot suck but squeeze the bulb fast and had to blow the left over part of the lead out of the hole. Repeat until the hole is clear. Stay clear of the front as hot solder will shoot out and you do not want to get hit with it.

4 - repeat on the other two leads and pads until all three holes are clear.

5 - put new triac in and screw it to the heatsink for alignment.

6 - solder the three leg to the pads and clip short.

You are done and no damage to the pcb.

RJ
 

[zwiller]

THANKS!  I was going to ask for triac removal protocol.   Happy to see removal of the heatsink is not necessary to change one. 

I recently changed one of mine using desoldering braid.  It did an OK job and I took my time.  I wanted to pass along that I ruined a board by pulling soldering tabs trying to pull a lead out with any kind of help or tools.  Not a good idea. 

(resisting from making a sophomoric comment regarding how the solder sucker works)