Garage door openers

[rwdenney]

In case anyone wandering into this thread is looking for an alternative to the current residential door openers, I can wholeheartedly recommend Zap commercial openers.

Zap

<p>Zap Controls garage door openers and accessories are a range of products with uses in both the commercial, residential and industrial sectors. North Shore Commercial Door carries their jackshaft openers, controllers, remotes and loop detectors at great prices. Their advanced products can be...

www.northshorecommercialdoor.com

They use DC motors, and using current draw to identify limits and obstructions they don't rely on programming or external sensors to set limits or to be safe. They do use beam-breaker safeties because of code, but won't kill anyone even if they close on a person (they will self-limit before serious injury). They are belt-driven on the jackshaft, and the emergency clutch simply releases the belt tension so the door can be operated manually. But because they are belt-driven, they are also very quiet--generally far quieter than the rollers on the door itself. They include outputs for lights and inputs for external radio receivers (I installed Liftmaster radio receivers on mine for remote operation).

They are somewhat more expensive than residential openers, but not really by enough to make them out of reach. I used the medium-duty openers in my shop but even the light-duty openers should be enough for the doors most of us will have.

Rick "installed four of them with all the accessories for $2500" Denney

 

[Provincial]

Right now I am fighting an old Lift Master chain drive opener that was installed in my in-laws garage, which is now a rental. The plastic gear was eaten up, but the worm gear and the rest of the unit were okay. I replaced the gear and re-lubricated the working parts. The repairs cost about $12.00 for parts and lubricant. It runs smooth and quiet (relatively, as it isn't ever quiet) but I'm having problems with the sensors.

I had to readjust the stops, which is normal when replacing the gear. Now it acts like the optical sensors are not hooked up, but they are hooked up, the wiring checked, and both sensors have steady green lights. The door opens normally. The door closes all the way when the wall button is pushed and held the whole way down. When pushing and releasing the button, or using the remote, the door moves down a foot or so, then reverses and the light flashes five times. According to the book, this indicates a problem with the sensor system. The lights stay steady green even when the door is in motion and reverses, which indicates that the both the sensors are getting power and can see each other. The wires are hooked to the proper terminals on the unit. They were not removed from the sensors.

I've ordered set of new sensors just in case. I have two other units like this, so if I don't need them, they will become spares. All three units have new gears now, and all lasted 20 years without problems or visible wear other than the drive gear. It cost me $10.00 for three gears, or you can get the gear mounted on the shaft with sprocket and upper bearing, grease, and small parts for $16.45 (p/n 41C220A) from a couple of places on Ebay. The kits come with full instructions, but I figured out an easier way to install all the parts, and an even easier way to replace just the gear. These were also sold under the Craftsman and Chamberlain brands.

I'm going to polish up the sensor wires at the terminals on the opener while I wait for the new sensors.

 

[markba633csi]

If you find the sensors are not the issue- Try replacing the larger power supply capacitors on the circuit board.
After a couple decades they can dry out and lose their value, causing malfunctions.
On something like a radio you can hear increasing amounts of hum from the speaker, but on a unit like this all you can do is replace parts and
cross your fingers.

 

[Provincial]

If you find the sensors are not the issue- Try replacing the larger power supply capacitors on the circuit board.
After a couple decades they can dry out and lose their value, causing malfunctions.
On something like a radio you can hear increasing amounts of hum from the speaker, but on a unit like this all you can do is replace parts and
cross your fingers.

It is more likely that something that I had apart to replace the gear is the problem. I had to unplug the circuit board for access, so I'll pull it apart again and use Deoxit on the contacts. I'll do that when I clean up the wires to the sensors at the screw terminals.

 

[cathead]

There's three relays one for the lights and the other two for open and close. By jumpering those to ground one at a time at the transistor side you should be able to get the motor to run. The leaf switch is normally closed for one direction, till it gets pushed by the door bracket/arm to stop
Statistically the problem should be at the backend power side rather than the RF front end
But not necessarily so

That's a great idea to activate the relays one at a time and see what gives. Also it was a huge revelation to me to be

That a great idea to be able to look up patent numbers to find schematics and other information. I have a television set that works
but is getting flaky probably due to bad electrolytic capacitors. I was just lucky that you saw the patent numbers
and looked it up for me. I was able to look it up too so know how now. Thanks Mark! You are a treasure indeed.

 

[cathead]

The problem likely is in this circuitry. I did short the relay outputs and the lights and motor operate just fine. I used an
internet converter program to convert the png to jpg format so I could print the schematic.

 

[markba633csi]

Best I could do considering how old the unit is...
I couldn't find a data sheet for one of the chips- apparently a special made by National for garage door openers
So that diagram in post #16 above is mainly just a big discrete flip-flop circuit. Give it a pulse and the door opens, another pulse and the door closes.
Most all openers work that way. The light relay is "ORed" to the output so it goes on with either direction.
You could probably troubleshoot that section with just a multimeter- but yours looks different; some type of hybrid
Some openers use a flip flop chip, some are discrete components. Some Stanleys used a small microprocessor to do all the logic functions
That SP8340 chip could be some dedicated type chip with the flip flop function and some other stuff in it- no data available for that guy
National chips are pretty rugged though- dollars to donuts it's not the chip

 

[markba633csi]

On the connector at the bottom there in post #16 pin 64 is the pulse input to the flip-flop. The other three are power and ground.

 

[cathead]

On the connector at the bottom there in post #16 pin 64 is the pulse input to the flip-flop. The other three are power and ground.

Can I use this input to try activate the opener? If so what would I apply to it? Likely a small + voltage I would think.
I metered out almost all of the parts and could find no discrepancies anywhere. Most of the electrolytic caps have
been ESR tested and replaced if needed. The circuit diagram is not too helpful since the parts are not specifically
identified. I have little interest to use the remote function, just want to get the thing to work with a wired button.
While I have not removed and tested the NPN driver transistors, they all read out the same so they are probably
fine. It's unlikely that they all would fail simultaneously anyway. I'm curious to know what the dotted lines boxing
in parts of the circuit might be for.

Diagnosing something overhead is probably the main difficulty. I may have to resort to removing the opener from it's
roost and put it on the bench.

 

[brino]

@cathead,

At one point in my life I received a box of Stanley garage door opener receiver boards and a couple transmitters.
The receiver boards looked identical to yours. I think I kept them because they seemed useful.

Give me a couple days (.....and then PM me a reminder!) I should be able to find them.

Help me to test them (what connects where, maybe using light bulbs instead of motors), and maybe I can send you a working one.....or two.....

Brian