Author Topic: SSR4 Resistor Burned  (Read 1745 times)

Offline Ron

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SSR4 Resistor Burned
« on: November 25, 2012, »
I have an SSR4 DMX version that one of the 180 ohm resistors fried on today.  I don't think it could be the opto coupler, so I'm thinking it has to be a bad Triac.  Does that seem reasonable?  That's pretty much all that is left to check.

Offline tbone321

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Re: SSR4 Resistor Burned
« Reply #1 on: November 25, 2012, »
It could be the triac.  Sometimes when they fail they draw the full load thru the gate which is what the 180 ohm resistor is connected to. 
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Offline Ron

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Re: SSR4 Resistor Burned
« Reply #2 on: November 25, 2012, »
That's what I was thinking.  Just reread and forgot to say I replaced the resistor first since it was easiest and I could find another one.  The new one burned too.

Offline n1ist

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Re: SSR4 Resistor Burned
« Reply #3 on: November 25, 2012, »
Check the soldering on the triacs.  They are connected to traces with a lot of copper on them and it can be tough to get a good solder joint,  If the triac is not connected, all the current will flow through the opto and 180R resistor.
/mike

Offline RJ

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Re: SSR4 Resistor Burned
« Reply #4 on: November 25, 2012, »
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Check the soldering on the triacs.  They are connected to traces with a lot of copper on them and it can be tough to get a good solder joint,  If the triac is not connected, all the current will flow through the opto and 180R resistor.
/mike

This is the normal reason this happens. I have seen it a couple of times and it was always because of a bad connection. on the triac.

RJ
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Offline Ron

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Re: SSR4 Resistor Burned
« Reply #5 on: November 25, 2012, »
I'll check that later but I think this one has worked the past couple of years.  Just started acting up I believe.  Any way to test the Triac?

Offline tbone321

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Re: SSR4 Resistor Burned
« Reply #6 on: November 25, 2012, »
There really is no need to test it.  Unless one of the joints has failed, the Triac has to be bad.  I would use your ohm meter and check to make sure that the solder joints are ok and if they are, then the triac is toast.  I would probably replace the opto as well since it took a few hard hits as well.
If at first you don't succeed,
your not cut out for sky diving

Offline Ron

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Re: SSR4 Resistor Burned
« Reply #7 on: November 25, 2012, »
Mike and RJ got it right.  Shoddy soldering on my part after a closer look.  Fixed the resistor and retouched the Triac and all appears to be working well.

I can also say I love my Bobcat DMX tester, great tool.

Thanks gentlemen for your help.

Ron