# Yet another garage door opener problem



## dotfarmer (Jan 27, 2009)

My Craftsman 1/2 HP garage door opener is blowing the garage circuit breaker. I found a burnt out ceramic disk capacitor on the terminal block where power comes into the unit. 

Most of the numbers are burnt off the capacitor so I don't have enough info to replace it. Does anyone have technical specs for a model 139.53415SR door opener (1991)? 

I tried PartsDirect but they don't have such a part listed. (Although they were willing to sell me the two screws that hold down the terminal block for $6, plus another $5 for shipping...)


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## Elvandil (Aug 1, 2003)

How big is the circuit breaker? Can you see exactly what the capacitor was connected to?


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## Noyb (May 25, 2005)

I have the manual for a 139.53985DM ... It does not show the parts for any Caps.
If it's near the power terminal block .. It sounds like a power line filter.
I'd guess any generic would work ... .001 or so.


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## Elvandil (Aug 1, 2003)

Noyb said:


> I have the manual for a 139.53985DM ... It does not show the parts for any Caps.
> If it's near the power terminal block .. It sounds like a power line filter.
> I'd guess any generic would work ... .001 or so.


That was my thought. But do you think that this alone could cause the breaker to trip?


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## Noyb (May 25, 2005)

If it's shorted .. and stayed that way.

I should have added ... 
The first thing I'd do is remove it .. And see if it still trips the breaker.


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## Drabdr (Nov 26, 2007)

When you say circuit breaker...

Are you talking about the one installed/attached to the garage opener, or the breaker feeding the 120vac plug for the opener?


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## JohnWill (Oct 19, 2002)

Sears parts has excellent manuals for most of their stuff, as well as spare parts.


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## Elvandil (Aug 1, 2003)

Drabdr said:


> When you say circuit breaker...
> 
> Are you talking about the one installed/attached to the garage opener, or the breaker feeding the 120vac plug for the opener?


Which is tripping and what amperages are both?


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## dotfarmer (Jan 27, 2009)

It's the 15amp breaker in our main service panel that's tripping, not the one on the door opener.

The capacitor bridges two terminals on the terminal block. I assume that one of the many power outages we've had recently caused a surge that fried it. I'm sure it's shorted, I tested it with a meter.

I was tempted to try it without the cap in place but I was afraid of damaging the circuit board. I'm one of those dangerous amateurs, and I really can't afford to buy a new door opener.


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## mrss (Jun 13, 2007)

Are you sure it's a capacitor? Not a surge protector?


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## Noyb (May 25, 2005)

mrss said:


> Are you sure it's a capacitor? Not a surge protector?


Good question ... How big was this component ???
I've been retired a while now .. but as I remember .. Surge protectors were about 3/4 inch in diameter .. or bigger


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## Drabdr (Nov 26, 2007)

dotfarmer said:


> It's the 15amp breaker in our main service panel that's tripping, not the one on the door opener.


Are you sure that your garage door opener is the only thing on that circuit? Also, is your breaker a ground fault breaker (typically a little red button on it to reset)?

Does it trip instantly, or does it take a few times?

I would find it strange that the opener would trip a 15 amp breaker much further downstream than the breaker (probably a smaller range) on the opener. But hey.. stranger things have happened!

If you unplug the opener from the circuit, the breaker should not trip. Try the opener (using an extension cord) on another circuit, or you can check the existing circuit to see if it is overloaded.

If the problem resides in the opener, then hopefully some of these electronic gurus can work with you getting it fixed.:up:


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## Frank4d (Sep 10, 2006)

If the part is wired directly between the two power wires then it is a surge supressor, also knows as a "MOV". Is it soldered to a PC board or attached with terminal lugs?


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## gophersnake (Mar 5, 2006)

About 10 years ago there was some sort of incident with a power pole in our neighborhood. The topmost crossarm with the highest-voltage wires fell onto the wires below and for a few seconds, all the houses nearby received about 4 times normal voltage.

I came home to a blown fuse that, when I replaced it, immediately blew again. I unplugged everything, replaced the fuse, and started plugging things back in one by one. When I got to the cord that powered the surge suppressor for my computer, there was a mighty crackling buzz from the surge suppressor and the lights dimmed. I hastily unplugged the cord and took a look inside the surge suppressor. It looked like charcoal and smelled like burned plastic. That finally taught me what it is that surge suppressors actually do: when the voltage gets too high, they blow the fuse or trip the breaker, quite possibly sacrificing themselves in the process.

I think Frank4d called it right: your "capacitor" is actually a varistor that got fried by a surge and is now drawing enough current to trip the breaker. More about MOVs (Metal Oxide Varistors) here.


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## dotfarmer (Jan 27, 2009)

My original post should have said "what appears to be a capicitor...".
It sounds like it's an MOV instead. The ice storms are over so our power should be okay now.
Will it be safe to put the opener back together without the MOV and just use a surge protected power strip instead?


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## Frank4d (Sep 10, 2006)

A surge protected strip should be ok for a temporary workaround. I would replace it eventually though.


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