Help identify a Zener?

[alwalker]

Re: Help identify a Zener?

Yeah any of those IC's will work really. Is yours a Liftmaster?

Yes. If you ever want to attract lightning owning one of their openers will do it.

[alwalker]

Re: Help identify a Zener?

The original was LM2903M. I already ordered some LM2903D ic's and the led from eBay. I think any of them will work that are 903 based although the LM2903DR would have been a better choice. I'll let you know how it goes.

The LM2903D and the power led were all that I needed. Everything works. I will set aside the sensor kit that I purchased and use it if the next lightning strike does more damage than can easily be repaired.

[redwire]

Re: Help identify a Zener?

you got the sensor emitter fixed
For lightning protection, I would add a mains surge protector (two MOV's) or the opener might already have them inside on the control board but they are pooched. It was an add-on change for some manufacturers.

[sam_sam_sam]

Re: Help identify a Zener?

The LM2903D and the power led were all that I needed. Everything works. I will set aside the sensor kit that I purchased and use it if the next lightning strike does more damage than can easily be repaired.

Thanks for posting your attempt repair and successful repair of your garage door opener because I also have a lift master brand as well I will have to look into it issue with sensor issues it might be related

[alwalker]

Re: Help identify a Zener?

you got the sensor emitter fixed
For lightning protection, I would add a mains surge protector (two MOV's) or the opener might already have them inside on the control board but they are pooched. It was an add-on change for some manufacturers.

I wonder if that's what is inside the Liftmaster/Chamberlain surge protector they sold for use with the openers? Do you perhaps have a schematic of that (990LM or CLSS1)?

[redwire]

Re: Help identify a Zener?

I wonder if that's what is inside the Liftmaster/Chamberlain surge protector they sold for use with the openers? Do you perhaps have a schematic of that (990LM or CLSS1)?

I don't see any teardowns or pics of the insides, to figure out the circuit.
Liftmaster 990LM/Chamberlain CLSS1 Garage Door Opener Surge Protector discontinued because new opener sales are down and lightning is up lol.
Liftmaster 41A5530 are add-on kits with two MOV's (Line-GND, Neutral-GND) seems to have no Line-Neutral MOV, similar to Wayne Dalton 252994 it is just a couple 150VAC 20mm MOV's. These connect to the control board terminal strips.

I'd suggest buying a decent mains surge protector to plug the opener into, or adding two or three (L-N, L-G, N-G) 20mm MOV's 150-175VAC rated, with built-in thermal fuse, someplace safe.

Littelfuse TMOV's which have a thermal fuse inside for added safety, same as:
Bussmann MOVTP MOVTP20V150N
Epcos/TDK ThermoFuse T20K150 or T20K175.

The 990LM also protects the sensors and switches against lightning, I would expect 4 MOV's or TVS to protect there, going to ground.

It kind of depends on how the lightning surge is getting into the house - through stikes to the powerlines (mains) , or ground strikes (ground).

[alwalker]

Re: Help identify a Zener?

I don't see any teardowns or pics of the insides, to figure out the circuit.
Liftmaster 990LM/Chamberlain CLSS1 Garage Door Opener Surge Protector discontinued because new opener sales are down and lightning is up lol.
Liftmaster 41A5530 are add-on kits with two MOV's (Line-GND, Neutral-GND) seems to have no Line-Neutral MOV, similar to Wayne Dalton 252994 it is just a couple 150VAC 20mm MOV's. These connect to the control board terminal strips.

I'd suggest buying a decent mains surge protector to plug the opener into, or adding two or three (L-N, L-G, N-G) 20mm MOV's 150-175VAC rated, with built-in thermal fuse, someplace safe.

Littelfuse TMOV's which have a thermal fuse inside for added safety, same as:
Bussmann MOVTP MOVTP20V150N
Epcos/TDK ThermoFuse T20K150 or T20K175.

The 990LM also protects the sensors and switches against lightning, I would expect 4 MOV's or TVS to protect there, going to ground.

It kind of depends on how the lightning surge is getting into the house - through stikes to the powerlines (mains) , or ground strikes (ground).

Thanks for the info. I can still get new 990LM units on Ebay. I have 2 doors with Liftmaster openers and installed one last year on the one that always gets damaged every year or so. I believe I will purchase another one today for the other door. In the event one of them does absorb the brunt of our next lightning strike I will definitely take it apart just to see what the circuit looks like.

[redwire]

Re: Help identify a Zener?

Take it apart, you know for the science
I'm wondering why Liftmaster discontinued the 990LM and if it is safety related?
Sometimes big corps don't want liability for MOV fires. I would want to know if the thing is safe.
Inside I expect three MOV's for mains surges, and four other parts for the control lines. Maybe a small MOV or TVS diodes. Maybe a fuse for the green LED.

P.S. Ha only recall is for new controls
https://www.cpsc.gov/Recalls/2023/Ch...d-Recall-Alert

[alwalker]

Re: Help identify a Zener?

Take it apart, you know for the science
I'm wondering why Liftmaster discontinued the 990LM and if it is safety related?
Sometimes big corps don't want liability for MOV fires. I would want to know if the thing is safe.
Inside I expect three MOV's for mains surges, and four other parts for the control lines. Maybe a small MOV or TVS diodes. Maybe a fuse for the green LED.

P.S. Ha only recall is for new controls
https://www.cpsc.gov/Recalls/2023/Ch...d-Recall-Alert

I'll have to see if the 990LM comes apart in a way that lets me put it back together again. Almost everything made nowadays in China "snaps" together and I would hate to break a new working surge protector right off the bat. That might be the easiest way though to get the right values for all of the components--definitely harder to do when things get burned and blown up. If I take one apart I'll post photos. I should be getting it delivered later this week.

[alwalker]

Re: Help identify a Zener?

Take it apart, you know for the science
I'm wondering why Liftmaster discontinued the 990LM and if it is safety related?
Sometimes big corps don't want liability for MOV fires. I would want to know if the thing is safe.
Inside I expect three MOV's for mains surges, and four other parts for the control lines. Maybe a small MOV or TVS diodes. Maybe a fuse for the green LED.

P.S. Ha only recall is for new controls
https://www.cpsc.gov/Recalls/2023/Ch...d-Recall-Alert

I took one apart that I just received--only three screws and comes apart easily. The 990LM does not use MOV's that have a built in fuse. The main board has mov's m1 and m2 as GNR20D431K and m3 is GNR14D431K. It does sandwich a thermal fuse between m1 and m2 and tape it all with what I suppose is a tape that will not go up in flames? The board that goes to the opener sensors and control uses a 14D201K. Since failure of that MOV would not result in the indicator led not lighting up I think I will take that one down and look at it to see if the MOV poofed when the safety sensor emitter board was damaged. After looking at the circuit I'm not all that sure that the thermal fuse is sufficient to keep it from being a fire hazard. That could be why it was discontinued.

[redwire]

Re: Help identify a Zener?

I posted a reply today but it seems to have vanished so typing it in again from memory.

Thanks for the teardown pictures of Liftmaster 990LM.
I drew a schematic for the Liftmaster 990LM and think it's a decent design and would use it if I lived in an area with lots of lightning.
The non-flammable insulating tape around the MOV's helps their heat get to the thermal fuse and pop it if the MOV's heat up. This was the way in power strips too for many years. It might be the liability that made Liftmaster discontinue these? Or they just want to sell you a new opener.

I did not know you already have one of these modules with the green LED out. Not sure if the TCO fuse popped or the LED died. Take it apart, do an autopsy I guess. If the fuse went, it should not have any power to the opener.

[alwalker]

Re: Help identify a Zener?

I posted a reply today but it seems to have vanished so typing it in again from memory.

Thanks for the teardown pictures of Liftmaster 990LM.
I drew a schematic for the Liftmaster 990LM and think it's a decent design and would use it if I lived in an area with lots of lightning.
The non-flammable insulating tape around the MOV's helps their heat get to the thermal fuse and pop it if the MOV's heat up. This was the way in power strips too for many years. It might be the liability that made Liftmaster discontinue these? Or they just want to sell you a new opener.

I did not know you already have one of these modules with the green LED out. Not sure if the TCO fuse popped or the LED died. Take it apart, do an autopsy I guess. If the fuse went, it should not have any power to the opener.

Thanks for the drawing. I scrawled pretty much the same thing out for myself already but yours looks much better. I didn't want to post the one I did because it looked amateurish. Perhaps I phrased it in a misleading way but I did not have a 990LM with green light go out. The one I have still indicated it was protecting the AC line. I was just referring to the fact that the emitter sensor board had obviously been damaged by lightning and after looking at the lightning suppressor circuit it appeared to me that the mov m4 could have been damaged in that strike and it would not have affected whether or not the green led on the module was still lit up or not. I did take it apart and verified that all of the mov's still appeared to be undamaged. Thanks for the drawing. I wasn't sure about the diodes off of M4 and it makes perfect sense that they would be zener diodes.

[redwire]

Re: Help identify a Zener?

If you are running one of the 990LM and lightning still took out the sensor, then I would also suspect the electrical panel ground for the home. If can be an old ground rod or plate that might be not working due to corrosion or bad wiring. Or the ground is too dry etc. Just something to inspect I guess.

What I have seen happen is between the garage door opener and the door rails you get high voltage, it's high frequency too and an arc or zap happens between them. I think the sensor/wall switch wiring acts like an antenna or something and picks up the lightning. The potential difference is between the mains ground (outlet) and the door rails I think.

New openers are terrible as I've said, tiny DC brushed motor and gears, have to authenticate with the server at head office and be on your WiFi network all the time. The belt drive is bigger than a rubber band but not by much. Chamberlain has cheapened their openers and hardware dramatically to the point you toss them out in the garbage every few years. So keeping old ones running is actually saving a lot of money.

[alwalker]

Re: Help identify a Zener?

If you are running one of the 990LM and lightning still took out the sensor, then I would also suspect the electrical panel ground for the home. If can be an old ground rod or plate that might be not working due to corrosion or bad wiring. Or the ground is too dry etc. Just something to inspect I guess.

What I have seen happen is between the garage door opener and the door rails you get high voltage, it's high frequency too and an arc or zap happens between them. I think the sensor/wall switch wiring acts like an antenna or something and picks up the lightning. The potential difference is between the mains ground (outlet) and the door rails I think.

New openers are terrible as I've said, tiny DC brushed motor and gears, have to authenticate with the server at head office and be on your WiFi network all the time. The belt drive is bigger than a rubber band but not by much. Chamberlain has cheapened their openers and hardware dramatically to the point you toss them out in the garbage every few years. So keeping old ones running is actually saving a lot of money.

I believe it has to do with the rails and sensor wiring. Almost every time I have had damage to the sensors you can see a scorched area on the pc board that leads back to the screw which mounts the sensor board and sensor to the rail. You can see it in the picture I uploaded. I will check the electric panel ground but I don't think I'll find a problem there.

[redwire]

Re: Help identify a Zener?

I see the mounting bolt, which is electrically connected to the mounting bracket and door rail and concrete floor, goes through the center and ends up close to the PC board. I did see one that arced through the seam in the housing to the bracket.
Strange the PC board traces around the hole go to internals. On the 14LG372 model it's to the IR transmitter LED so that gets zapped. As if Liftmaster knows something how to cause failure lol...

[alwalker]

Re: Help identify a Zener?

I wonder if anyone makes a residential opener that uses wireless safety sensors and wireless door opener switch. That would pretty much eliminate almost all of my lightning strike issues. I wouldn't mind changing a battery or two once a year--people do that already with smoke detectors in their house.

[redwire]

Re: Help identify a Zener?

I've never seen any, I think because it has a safety function i.e. the door sensors will stop a door opener if they go dead as well as when there's an object present so they'd have to transmit a blip quite often. Using a light beam takes a lot of power too. Big battery probably.

[sam_sam_sam]

Re: Help identify a Zener?

1.5KE39A.

The part number for the bottom circuit diagram is this

1.5KE39A when try to copy and paste the part number it drops the 1. and only show the 5KE39A
Just posting this in case someone tries to copy and paste the part number to find the date sheet

[redwire]

Re: Help identify a Zener?

Not sure where the part number is not working? The 990LM schematic is just a picture. I could post a bill-of-materials if you are making one.

If I lived in Florida or Texas I would definitely have lightning protector on the garage door opener.

[sam_sam_sam]

Re: Help identify a Zener?

If I lived in Florida or Texas I would definitely have lightning protector on the garage door opener.

This is the reason I have been closely watching this post after you mentioned about how to maybe survive an indirect lightning strike directly getting hit with a lightning strike nothing is going to help this