[captfl2x]

Power came back on after power outage. I have a DVD that no longer works and a garage door opener both on separate circuits. The circuit breaker was not tripped and using a lamp ( without a ground) I had power at the opener. I also had power to a nearby GFCI on same circuit. When the garage door service man replaced the circuit board and plugged the unit into the outlet there was a pop and the breaker tripped. The plug for the opener also had slight (arc ) damage to both the hot and neutral prongs. Where and what am I looking for to fix this?

 

[joed]

Sounds like the door opener repair guy made a goof.
Are there any lights on the same circuit? Do they work?

 

[captfl2x]

My outside flood lights worked before the breaker tripped. Door opener service guy checked the door opener again and said I had an electrical problem. He did not charge me for a ruined circuit board.

 

[captfl2x]

I reset the breaker and verified with a 2 prong lamp that current was to each outlet. I then used a computer monitor that was going to a yard sale. Monitor has the three prong plug which I plugged into the door opener outlet. Monitor turned on without issue. Plugged monitor into upper and lower of out---No issue. Looks like the problem is not with the wiring.

 

[zhawkeye]

At this point, I agree with joed...sounds like the service guy connected the new board incorrectly...he needs to install a new board and verify the connections before applying power.
As far as the DVD, it may have been taken out when you lost power...don't know and can't tell at this point. Look for an external fuse...if none, without power to the unit, open it up and look around for a PCB mounted fuse (or maybe an in-line fuse)...it's not uncommon for manufacturers to place them there...

 

[Calson]

A surge can easily damage a single component on a circuit board and then whatever it is in will no longer work properly. As chips have gotten smaller the insulating silicon between the internal ciruits/transistors has gotten thinner and it takes less of a surge to cause damage.

A first step is to have an electrician wire in a whole house surger protector. These sell for under $100 and protect without having to buy a surge protector for everything in the house.

For expensive items like a TV or computer a UPS type surge protector provides greater protection (from surges and from sags in voltage). The cheap "surge protectors" will have a MOV chip and nothing more and when this chip blows the surge protector will pass the next surge and cause more damage than no protector at all. At the very least get a surge protector that has a light to indicate that the MOV is intact.

 

[joed]

With a spark like you describe it sounds like the GD repair guy somehow had a direct short on the power lines. He either connected something wrong or missed an insulator when he screwed the board down to the metal chassis.

 

[surferdude2]

There is an outside chance that your door operator is one of the kind that has a separate power supply board (Liftmaster makes one), apart from the control board. There is a power transformer on that board. It's always connected to incoming power constantly. It's possible that a line surge could have shorted the primary winding of that xfmr and that would cause the problem.

You can eyeball that and easily tell if it has another board or a remote transformer.

There is also a socket and light bulb with wiring that gets energized as soon as the power cord is plugged in and later times out.. Check that circuit for a possible short.

Aside from that, It's back to looking bad for the tech.

 

[zhawkeye]

If that's the case, surferdude, and the transformer and light get power when connected to AC, then he could just plug in the cord and see if it trips the breaker...if not, they're not shorted...

 

[surferdude2]

If that's the case, surferdude, and the transformer and light get power when connected to AC, then he could just plug in the cord and see if it trips the breaker...if not, they're not shorted...

True for the transformer, depending whether it gets fed from the board or not.

As for the light, only if the board is there and working properly since the time interval of the light is done by the chip on the board. He could take some ohmmeter measurements to check for a short.

The odds are the tech goofed up but we can't assume that. Personally I wouldn't buy a new board and use it for a test device to see if it smoked when activated. lain:

 

[surferdude2]

Of the two, the transformer would be the most likely (although slim chance) since it was the only thing that was connected while he was away on vacation. The light only comes on when the board is initially activated or when the operator is activated to open the door... unless he has one of the systems that has a light switch actuator button also.

 

[zhawkeye]

Now I'm on the same page...when you mentioned they always have power, that was IF the board was present...I misread it...

 

[surferdude2]

Those boards are made so that everything plugs in... so removing the board removes all power cord and load connections. They keep it simple so that door installers don't have to be electricians.

Then you get repair techs that only know how to plug something in or maybe plug something in wrong. The poor OP is seeing the results of that type of business model.

 

[Old Thomas]

Power surges do strange things.
Years ago lightning struck a pine tree close to our house. A turned off but plugged in phone answerer turned on and started beeping, the cellar gfci tripped, and our cooktop hood turned on and would not turn off because the circuit board was damaged. It was such a brief surge that no breaker tripped.
On 3 occasions I saw garage door openers that were killed by lightning. The doors were all closed. The strike made them open and then they never worked again. That is why I turn off the breakers to my door operators when I go on vacation.

 

[captfl2x]

I insisted that there was nothing wrong with the ceiling outlet and wiring. Company sent another tech. He checked the outlet and pulled the circuit board. He showed me the very slight damage to the board that is connected to the motor. Motor was toast & also replaced board.

 

[bfrabel]

So they installed another new control board and a new motor? Is it working now? I'm surprised there are companies out there that actually repair those things. I would have thought that it would be cheaper and better to just replace the entire unit.