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Jerry Ludy

Traics continue to FAIL, why?

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Dang, all of this bad jue jue has hexed me. Now I have a string on at 100%. Opened the box and the Triac related to this string of LEDs does not have a screw holding it to the heat sink. I cant believe I forgot to install a screw. And did not give the box a good looking for the screw. I suspect that the LEDs (one string of 100 C6) was enough to blow it. Must have been some of the rain/ice that did me in too.  Oh well looks like I am going to join everyone else replacing a Triac. And then make sure it is screwed to my home made heat sink. I only run LEDs thus only a few amps. So my piece of 1.5" angle aluminum does the job. And it is just a bit longer so I can use it to screw into the box to mount it.

I just had my first one ever let go Christmas night, only had a single 100 count of incandecents on it. Fine times during the offseason now

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I should have said also that with 80 watts. Do not stay on the joint more than 4 seconds. Or you might burn the board and lift pads as dgrant stated.  Give the kid an old board and tell him to show you his technique. Hey we all need to learn by doing and you will be giving the kid a chance to help and build his skills. But he has to agree to back off if you ask him to.

 

WOW 80 watts?

 

I run 25 watts and it works fine for the normal component solder pads.

For the big power pads I use a 40 watt.

For the small LED strips, I use a 15 watt soldering iron with lots of soldering paste.

Desoldering, I use solder wicks.

 

Whatever works; everybody has their own method.

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Once you've soldered enough Triacs, you get a feel for how they should 'flow' when installed.  I personally use a cheap 40w Weller station.  I like to get a nice sized 'puddle' of solder onto the leg and pad, and continue to heat the joint for a few seconds.  All of a sudden you will see the puddle 'slump' down into the through hole - the point where there is enough heat to get a nice connection.

 

Of course, soldering is an art.  I lifted plenty of pads when I started.

 

As for removal, I suggest a cheap bulb-desoldering iron.  They are a lot easier to use than wick (which you should also have handy), or those separate hand opperated solder pumps.

 

The easiest way to lift a pad is by NOT completely desoldering something.  You should never 'rock' or 'wiggle' a component that is still stuck after 'desoldering'.  If it doesn't come out, then there is still solder present.  Rocking it is going to rip the pad clean off the board.

 

If you have a lot of parts to change out, I personally would invest in an inexpensive vacuum desoldering station or hot-air rework setup.  

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Once you've soldered enough Triacs, you get a feel for how they should 'flow' when installed. I personally use a cheap 40w Weller station. I like to get a nice sized 'puddle' of solder onto the leg and pad, and continue to heat the joint for a few seconds. All of a sudden you will see the puddle 'slump' down into the through hole - the point where there is enough heat to get a nice connection.

Of course, soldering is an art. I lifted plenty of pads when I started.

As for removal, I suggest a cheap bulb-desoldering iron. They are a lot easier to use than wick (which you should also have handy), or those separate hand opperated solder pumps.

The easiest way to lift a pad is by NOT completely desoldering something. You should never 'rock' or 'wiggle' a component that is still stuck after 'desoldering'. If it doesn't come out, then there is still solder present. Rocking it is going to rip the pad clean off the board.

If you have a lot of parts to change out, I personally would invest in an inexpensive vacuum desoldering station or hot-air rework setup.

If you have a lot of parts to change out, I personally would invest in an inexpensive vacuum desoldering station or hot-air rework setup.

Agreed. I use this one for all my different hobbies... and day job once in a great while... ;)http://www.amazon.com/Hakko-808-KIT-Contained-Desoldering-Internal/dp/B00FZPTEK2/ref=sr_1_1?s=hi&ie=UTF8&qid=1388262288&sr=1-1&keywords=hakko+desoldering

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I like the higher wattage cause I can get on, and off in matters of seconds. This will help NOT transfer to much heat to the board or just if not more important is the component that is being soldered. But at the same time, if you linger to long, It becomes easier to damage the board. Don my my years of working on boards I have found that there usually is always going to be trace of solder left behind. Usually the pin or lead is not perfectly in the middle of the hole. Where the pin or lead is touching the wall of the hole, there will be some solder. When I remove things like I.C.s DIP I have been known to take a small screwdriver and push the pins towards the middle and then back out to the outer edge. That usually has been a good practices for me. I have always used one of those hand held suckers that are spring loaded. Rarely, but from time to time the wick. The wick takes more time and thus more heat to the board. Thats when I have lifted the pads, cause of to much heat.

 

Just my observations over the years.  But you are 100% correct, it is a skill, just like playing a musical instrument or painting.

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I've only done one TRIAC. But after I removed the heat sink I cut the leads at the body of the device. I rotated between the three leads and cut a little bit each time till I was through the leads (to prevent stress). After that I reflowed the solder, pulled the leads and wicked the holes.

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I got your PM with the ticket number, and you are absolutely correct -- rather than offer to send you some, we only gave you some links to buy them.  We really dropped the ball, I apologize for that.

 

I'm going to re-open your ticket and get some sent to you.

Hey Mike, never did receive these? Now that the lighting season is finished I'd like to replace them.

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Hey Mike, never did receive these? Now that the lighting season is finished I'd like to replace them.

 

Probably got lost in your eMail.  I re-opened your ticket and asked for your shipping address.  I didn't receive a reply.

Thu, Dec 5 2013 1:53pm - Mike DeMaria (Software/Visualizr What is your shipping address, please?

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PM on its way... thanks again Mike!

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Just to follow up... I found your email Mike in my old email account's inbox dated 12/05/2013.  I changed my email address in the LOR system for my license and I just assumed it would change it for everything LOR related.  I'll look into changing it for everything else now.

 

BTW, also found your new email from today in that same inbox.

 

Thanks again!

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Finally tally for me this year was 6 failed triacs with 3 on one controller and 3 on the another.  In total we have 19 LOR controllers and these were some of the newest(I think they *are* the two newest tbh and were bought in the last two years).

 

Replaced the failed triacs with eBay bought triacs and kept the 3 free replacement triacs LOR sent as back ups.  The markings on the LOR provided and the eBay bought triacs are almost identical except for the lot number.  The triacs that failed have strange markings compared to these, even though they are supposedly the same brand?

 

Just funny that I didn't have this problem the previous 5 years and once I switched off the defective channels all was good.  I'm chalking it up as defective triacs.

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Yes. Triac tester here: http://www.ebay.com/itm/Atlas-SCR100-Thyristor-and-Triac-Tester-/161061126371?pt=LH_DefaultDomain_0&hash=item257ffdc0e3

 

I have one and it works very well.

 

This triac is about the biggest you can get at 24 amps without outgrowing the circuit board.

 

Keep spares if you need to.

 

I have theatre type of dimmers that can use the bigger 40 amp versions.

But they have a bigger spread on the terminals and won't fit into LOR devices.

Ken that Triac link is bad or at least I am not able to get Mouser to bring it up. Can you verify it, thanks.

Edited by zman

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Just a note, about triac's (there's that word again !)

 

Heat sinks, the size of heat sink (and the traces on the PC board) is/are going to determine what amperage a channel can handle (NOT just the Fuse).

 

IF the channel is ONLY on/off (no dimming used) then it will be the copper traces on the board that will be the limit, If DIMMING is used then it's the size of the heat sink, so here's the thing, the triac displaces the other portion of the AC waveform, into the heat sink (instead of the bulbs)  when dimming, if you are 50% dimmed, then the other 50% of the load goes into the heat sink.

 

Example: 1000 watt load at 50% brightness will cause 500 watts to be "sinked" into the heat sink. Have you ever felt a wall dimmer with it being dim for a while >?  they get quite warm.

 

The LOR boxes (and heat sinks) are designed for only so much amperage or current, you could get quite costly if you start installing bigger triac's into them.(blowing traces off the board).

 

HOWEVER, being a person that used to build theatrical stage dimmers,  one could use the LOR board (new case or enclosure) and different heat sinks (and a modified wiring system) to used HUGE 40 amp heat sinks on ALL the channels of a LOR board, right up to their rated output !!!

 

40 amps at 120 volts = about 4600 watts per channel times 16 = over 72 kilowatts of light !

 

Greg

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Half power on a 1,000 watt load does not put 500 watts into the heat sinks. The LOR heat sinks are not rated anywhere close to dissipating 1800 watts that a dual inlet controller would have to at 50% under your assertion. Do you really think they could handle the output of a portable space heater into those sinks, not having as much area, not the fans?

Your statement is closer to true for an analog dimmer using transistors, but I don't think I have ever seen that design, only phase angle, where the switching losses are much smaller.

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i've had three channels fail me this year on a controller that was a year old (g3), two in the beginning of the Christmas season and one in the middle.  The first two i was able to swap the channels with another controller the third i just had to suck it up and let it stay on all the time.  I reported it to LOR and they sent me replacement triac's no questions asked.  Things fail that's a fact of life but good service is sometimes hard to come by and i have to say the response i got from LOR was second to none... Thank you LOR.... 

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KLB, I'll agree that the 1/2 load thing is not truly accurate, but the idea was to let people understand that there is a penalty to pay if using larger triacs...

 

Since we have an edit button again, I'll correct my statement.

 

From a textbook I have.

 

Calculation of heatsink size
To calculate the required heatsink thermal resistance
for a given triac and load current, we must first calculate
the power dissipation in the triac using the following
equation:
P = Vo x IT(AVE) + Rs x IT(RMS)
2
.
Knee voltage Vo and slope resistance Rs are obtained
from the relevant VT graph in data book of factsheet. If the
values are not already provided, they can be obtained
from the graph by drawing a tangent to the max VT curve.
The point on the VT axis where the tangent crosses gives
Vo, while the slope of the tangent (VT/IT) gives Rs.
Using the thermal resistance equation given above:
Rth j-a = T/P.
 
Greg
Edited by a31ford

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I own 10 of the PC units and 2 DC units. Just did my 4th year. Just had my first bad triac. Part of it is cause I must have missed installing the screw and nut for this channels. Although 1, 100 cnt LED string should not kill it. I think that the ice must have added to the load, enough to damage the Triac. So, I am feeling fairly lucky compared to what I am seeing others users are having.

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OK.. reality check on triacs and heat.  Assuming normal operation for the following.

 

When a triac is in the off state it dissipates virtually no heat.  When in the on or in the conduction state, they dissipate about 1 watt per amp, (round numbers).  They drop approx 1 volt when in the conduction state so 1 amp x 1 volt equals 1 watt. (again, round numbers). 

 

Whether you use 12 amp or 30 amp triac is pretty much not relevant heat wise.  They will dissipate about the same heat given the same load. 

 

There is no in between state, either they are on or they are off, (actually there is a rise time of about 3-5us and there is heat developed during that time, but that averages very little in the scheme of things).  That is why phase angle control is so inexpensive to make and use.

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Plasmadrive - I think you've got it there.

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I own 20 of the CTB16PC units purchased over a course of 6 years. I had triacs go out more during periods of large rain. And as noted before, the triacs would fail between the end of a show and the next evening (before the show).

I had a bunch of blown triacs in 2011 because that was the rainiest season for me in the 6 years of using LOR. And I had many triacs fail on channels that only had a single strand of LED lights.

On a side note, a lightning storm this past Dec 30, 2013 caused a huge amount of triacs to blow, but this is not a normal case (of a lightning storm that is).

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On a side note, a lightning storm this past Dec 30, 2013 caused a huge amount of triacs to blow, but this is not a normal case (of a lightning storm that is).

 

That's interesting. There has been speculation before that some of the TRIAC issues were related to ESD hits. If they were it could explain why the occurrences seem somewhat inconsistent. I also think other issues sometimes get misdiagnosed as bad TRIACs because they get discussed so much.

 

I'm up to 15 controllers after six years and had my first bad TRIAC last year. I'm using all older controllers.

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Isn't the real problem is that LOR designed the output triacs without fuse protection? There would be NO blown triacs if LOR had incorporated current protection (fuses) in their designs. --Greg--

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Actually, no, and for one simple reason.

 

the fuse requires an over amperage condition for a long enough time that the triac would pop the junction (silicon junction internally) would pop, faster than the melt-able link within the fuse (I'm talking fast action type fuses).

 

ALSO, it would give a person the chance to install higher current fuses (defeating the purpose in the first place), AND, add a large cost to the controllers for nothing.

 

Better wiring practice AND testing of light strings BEFORE they are installed, greatly reduces the shorting out of triacs in the first place.

 

Greg

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