Garage door opener struck by lightning?

Something the electrically minded may enjoy and related to cars because people sometimes actually use their garage to park cars… I believe people enjoyed some of my prior postings related to these kind of repairs so here goes-

Symptom- opener stopped working, just clicks once and no motion at all. Lights do not illuminate. Diagnostic LED flashing 5 times.

Background- User manual states 5 flashes is miscellaneous fault. If power cycle does not fix, then replace control board. Preliminary research shows same basic control board used for many different brands of opener.

Diagnosis- Removed control board. Visual inspection reveals one SMT SOT323 package device has back blown off. Reverse engineer entire circuit. Affected component is an NPN driver transistor for the light relay. There are three of the same circuits; one for light, one for motor up and one for motor down relays. Blown component is dragging down power supply for board.

Interesting detail- controller is PIC variant. Has custom part number but likely due to mask ROM programming. All other details match commercially available PIC controller.

Repair- Replace all three SMT transistors with general purpose 3904 NPN transistors (2x Ic rating). Opener now functions but will not close door due to error with safety reversing sensors.

This is where it gets more interesting. How do the sensors work?
I know they are infrared but is it more complicated than an emitter and detector?
Here’s a pic of the inside of the receiver module-

Here is the reverse engineered circuit-

The receiver IC is actually a small module designed to receive modulated data over infrared. It is not being used in that way however.

To provide an extra measure of safety in the design, a pulse of a specific frequency and duration is generated when the receiver detects the IR energy from the emitter.

D1 isolates the two sides of the circuit. As U1 output transistor conducts when it sees the IR, it causes Q2 to produce an output pulse that drives Q1 and crowbars the input voltage. This also turns on the LED to indicate the receiver is aligned with the emitter. Pulse train is low ~0.5ms and repeats at ~6ms rate.

The control board micro looks for the right pulse frequency from the safety sensors to ensure nothing is in the path of the closing door.

Q1 was damaged and not doing its job. Once replaced, it began working properly again.

If you decide to work on your own, be aware that you need a current limited supply. The control board has a 2W 200 ohm resistor feeding the sensors to limit the current when Q1 turns on. If not, you’ll burn it up in short order.

All of these failed transistors have connections to the supply side and most likely were damaged during some transient event- like a lightning storm. Strangely enough, I have three openers in close proximity and only one was fatally damaged.

Price for new control board and sensors- $110+
Actual cost of failed components- ~$0.25
Things learned- Pricele$$


hmm, i misplaced my remote and tried to use the reprogram button on opener for a 2nd remote i had. different frequency so no go. of course i found remote after 3-4 days but now the opener opens door randomly. according to website my remote should not work with my opener. but it does.

Most time its the batteries that are bad inside the remote transmitters and the batteries inside the keypad.Sometimes I just clean the contacts inside the keypad and it works again.

Nice job on tracking down the problem and fixing it. Unfortunately we now live in a repair by replace environment. People no longer have the skill to trouble shoot or if they do their labor cost is too high.

Lightning is a very strange animal. Some years ago my neighbors tree got hit by lightning, maybe 40 or so feet from my house. Blew the bark off the tree from mid way to the bottom about 6 inches wide. Knocked a picture off one wall in my house and fried a modem. The modem and cable entry were on the other side of the house but somehow the lightning found it’s way in. The tv was turned on, we had turned it off before we left, but it was otherwise undamaged.

my remote works “too” well? or at least the opener works too often.if my battery is weak than why does it operate the opener at random times? opener never had an issue until i pushed the program button. my opener has no internal keypad or anything to adjust. like the 1-10 key pad. but the remote does have the internal keypad or keys

Does the unexpected operation stop if you remove the batteries from the 2nd remote?

You have more patience than I do. I would either just order a new board or replace the unit for about the same price. Where do you even get transistors anymore with Radio Shack on the ropes?

Digikey, Mouser, Newark, Jameco… the list goes on.
Or, you just go in the lab and pick out one off a reel that’s close enuf :slight_smile:

I forgot, the control board also had a diode that was fried. For that, I just fished one out of a bin I had at home that was probably 20 years old. The only issue was the amount of oxidation on the leads after all that time exposed to the air.

Changing the entire unit would be last resort. It’s 9ft off the floor and 4 ft below the ceiling…

We had a similar incident. A lightening ball exploded in the back yard about 15 feet off the ground. It discharged into the ground and our home’s cast iron sewage pipe was directly below the discharge. It seems the electromagnetic pulse traveled to our house and discharged when it hit the PVC interior piping. We have an Ethernet cable within 3 feet of the sewage pipe, and apparently it acted as an antenna and conducted the pulse to a nearby computer then to the cable modem, another computer, the WiFi router, VOIP modem, and the cable TV box.

When the pulse exploded at the PVC pipe, it lit up the inside of the pipe. That blew a couple of holes in the PVC pipe and blew off the service Y-pipe, the pipe movement also blew out the bottom of the wall in that room where the pipe is located. I smelled smoke and called the fire department. It turned out there was no fire, just residual smoke from the sewer pipe explosion and the fried VOIP unit. It cost me $1000 to recover and cost the insurance company more than that.

About 20 years ago a good friend who is a home builder was at home one Saturday night watching a late movie on TV. He fell asleep on the sofa right before severe storms rolled through around 1 in the morning.

Lightning hit the chimney and caused all kinds of havoc. It knocked him off the sofa, dislodged bricks in the fireplace, knocked all 3 garage doors out of their tracks and threw them almost a 100 feet to the roadway.
Sheetrock nails were popped out all over and the screaming was his 9 year old daughter who was asleep in bed until half a sheet of sheetrock fell on her. Thankfully she suffered no more than a few bruises.

It amazed me to see 3 nine foot wide garage doors tossed that far. The concussion of the strike peeled all of the outer hinges and rollers loose.

Very interesting, good post. I’ve never fixed one of the newer types of openers like that one, but in the old types I’ve had to replace relays numerous times, and occasionally had to re-tune the remote’s rf transmitter frequency to match what the receiver was expecting.

The last opener I had used a belt which broke and wasn’t economically fixable. The motor and remote control still work, but haven’t come up with an application to use it yet. I was thinking it might could be put to use as a log splitter if I were clever enough. Which I’m not, so it sits in the junk box … lol . .

I think the lesson from all of this is to use surge protectors for all sensitive electronics - TV’s, stereos, computers, etc. If I recall correctly, you can add a capacitor in the main circuit into the house.

Note to self: When you dispense advice, you ought to take it yourself.


My house was hit by lightning and the garage door opened. The heating element in our electric oven vaporized, the TV antenna wire also vaporized. My clock radio went on and never turned off again. We had lightning rods all over the roof, which worked because those were our only losses.

Different house, different state now, my garage door often won’t close on sunny afternoons in November and January, and I discovered it’s because the sunshine reflects off the polished concrete floor into the motion sensor. I put pieces of carpeting across the floor at the door area, a strip about 15 inches wide all the way across, and it’s happy again. My son-in-law moved the sensors in his garage to the wall above the garage door, so they can see each other all the time, no sunshine ever gets up there, of course they don’t provide any safety function any more.

One of my doors gets sunlight interference in summer afternoons. Pressing and holding the hardwired control button overrides the safety sensors so it can be closed.

Sometimes just taping a piece of cardboard to the sensor to shade it will stop the sunlight problem.

It only happens if I’m closing it at the right time, a couple hour window in late afternoon and only a few weeks during summer so no problem to just hold the button until it closes those few times. If it was more frequent, I’d certainly try shielding. The manual has this tidbit about overriding but it’s barely noticeable, probably by design.

More likely a gas explosion in the garage.