Electronics guys (not Sea Six), I need some help

[Kevin_73]

I'm hoping that someone might be able to give me an idea of how to fix the control board for my sliding gate opener!

This is the second one that has fried (to the tune of $200 each). I'm pretty sure the failure mode is that it closes the gate, but does not shut the motor off when it hits the limit switch, then the motor keeps running til something (else) in the board fries.
I've been able to determine that motor still works fine, and that the battery charging circuit is still working, and the receiver part of the board is still working. It just won't switch on the motor (relays not clicking, no power to motor output).
I suspected the relays (four black rectangular components on the lower left), so I replaced all of them. Board still does not work.

Nothing looks scorched or distorted. All the diodes and transistors check out ok with a multimeter, and I as far as I can tell the capacitors are all ok too (but I don't have the proper meter for those).

http://i221.photobucket.com/albums/dd18/KWHITLOW/DSCN0407_zpsa1a85c84.jpg

I have ordered another control board (the third one now), but I would like to repair the two existing ones so I can have spares for when this happens again. Any ideas on which component(s) might be the culprit?

[DropTheTop]

:lol: You had me at not Sea Six :lol:

[snide]

Should be able to fix it with a BFH. :dunno:

[ZipZap]

Check the operation of the voltage supply sitting on that big heatsink.

[Aerovette]

You have programmed parts on there and you won't see signs of damage necessarily. I can't say what is going wrong, but the issue may not be visible.

[73sbVert]

See if you have power voltage, and control voltages are available to switch the relays on/off.

Like ZipZap, I suspect the voltage supply circuit.

[ZipZap]

I can't see any markings on the regulator, does it have any?

[jaxgator]

:lol: You had me at not Sea Six :lol:

Same here. :funny:

[Kevin_73]

Check the operation of the voltage supply sitting on that big heatsink.

I suspected that, but after looking at the the datasheet on that component I came to the conclusion that it is part of the battery charging circuit, and that part of the board is still working properly.
It has a 18VAC (from a transformer) input on the bottom left, and a output/input to a 12V gel cell at the top. It appears that all of the circuitry on the far left side of the board is for the battery charging.

[mrvette]

OK, does that board run a AC motor?? or a DC motor, what voltage does the motor run on?? where is the control board mounted?? inside or outside?? does it also have a transmitter in the car like a garage door opener?? what limits the opening/closing of the gate?? is it a switch or a sensor??

I tell you what, that board is totally over engineered from your description of it's function....and so that supply on the board, looks as if it takes 110 vac input and turns it into a voltage to run the rest of the board....

I feel a simple relay setup would do the job you need and it's in my car for the windshield wiper door on my '72 vette, electric operation for years now, not vacuum.....

so combined with a simple remote receiver/trans you can do your own more reliable setup.....

:seasix::hurray:

[Kevin_73]

I can't see any markings on the regulator, does it have any?

The component on the heat sink is most likely the voltage regulator.

[ZipZap]

The component on the heat sink is most likely the voltage regulator.

It is. I was just wanting to see if it was dual voltage. I'm guessing that if it's part of the charge circuit, the extra leads are probably for overvoltage protection vs. anothe voltage.

What's the part # ?

[ZipZap]

Is there an interlock that prevents gate movement if something is in the way?

[Kevin_73]

OK, does that board run a AC motor?? or a DC motor, what voltage does the motor run on?? where is the control board mounted?? inside or outside?? does it also have a transmitter in the car like a garage door opener?? what limits the opening/closing of the gate?? is it a switch or a sensor??

I tell you what, that board is totally over engineered from your description of it's function....and so that supply on the board, looks as if it takes 110 vac input and turns it into a voltage to run the rest of the board....

I feel a simple relay setup would do the job you need and it's in my car for the windshield wiper door on my '72 vette, electric operation for years now, not vacuum.....

so combined with a simple remote receiver/trans you can do your own more reliable setup.....

:seasix::hurray:

The motor is 12V DC
There are two limit switches to define the open and closed positions of the gate.
The input to the board is 18VAC (from a transformer)
The board is mounted in a plastic enclosure within the gate operator.
There is a transmitter in the car.

It is designed more complicated than it has to be because it has to accommodate all the possible safety features (inductive loops, infrared sensors, etc). It can also be wired to another gate operator if you have a dual sliding gate (none of which I am using).

[ZipZap]

Went to the GTO website. Is the obstruction sensor ok?

[Kevin_73]

It is. I was just wanting to see if it was dual voltage. I'm guessing that if it's part of the charge circuit, the extra leads are probably for overvoltage protection vs. anothe voltage.

What's the part # ?

MIC4576WT datasheet(1/8 Pages) MICREL | 200kHz Simple 3A Buck Regulator (http://html.alldatasheet.net/html-pdf/407427/MICREL/MIC4576WT/218/1/MIC4576WT.html)

But, like I said, the battery charging circuit is working fine. Battery is staying charged and when the battery is disconnected there is voltage (I think it was 13 or 14V) to the Batt terminals at the top of the board, and both LED's are still on.

[Kevin_73]

Went to the GTO website. Is the obstruction sensor ok?

It does not have any external sensors connected to it. I think the board itself senses higher amperage load from the motor to determine if there is an obstruction.

[ZipZap]

MIC4576WT datasheet(1/8 Pages) MICREL | 200kHz Simple 3A Buck Regulator (http://html.alldatasheet.net/html-pdf/407427/MICREL/MIC4576WT/218/1/MIC4576WT.html)

But, like I said, the battery charging circuit is working fine. Battery is staying charged and when the battery is disconnected there is voltage (I think it was 13 or 14V) to the Batt terminals at the top of the board, and both LED's are still on.

Yep, those extra two leads are shutdown and feedback. I'm guessing the doughnut is the filter for the 220kHz switching.

The motors likely run off the battery and the transformer is for charging.

[Grey Ghost]

I have a commercial grade swing gate operator. I know you want to fix this board. But, what are you doing to prevent damaging the new one? Good ground? Anyway to put a fused link from the motor to board? Or surge protection?

[ZipZap]

It does not have any external sensors connected to it. I think the board itself senses higher amperage load from the motor to determine if there is an obstruction.

It does. Put an ohmmeter on the "Obstruction Sensor" potentiometer outputs and see if you get any conductivity.

[Kevin_73]

The motors likely run off the battery and the transformer is for charging.
Exactly

It does. Put an ohmmeter on the "Obstruction Sensor" potentiometer outputs and see if you get any conductivity.

Yes there is conductivity.

[VatorMan]

Dimes to a dollar I'll put money it's on one of those relays. Those are notorious for failing.

[ZipZap]

At the top of the board, right under "batt", those may be fused links. Can you test the conductivity?

[Kevin_73]

Dimes to a dollar I'll put money it's on one of those relays. Those are notorious for failing.

That was my first thought too. So I replaced all of them.

[Kevin_73]

At the top of the board, right under "batt", those may be fused links. Can you test the conductivity?

Both good

[ZipZap]

Thinking about it a little more, even if the limit switch doesn't operate correctly, the obstruction circuit should not allow the gate to stay closed if operating properly.

You have any lightning lately?

[GS Ragtop]

Well, I don't know about the other board, but the fault of the board in your picture is pretty obvious -- F1 and F2 are missing.

j/k


You said the motor is 12VDC -- does it have a separate power supply that's switched by this logic board? If so, I wouldn't be so certain of your failure mode -- the board should only have motor current running through the relay contacts.

If the board does provide current for the gate motor, I'd suspect either the big capacitor or the voltage regulator chip. Either (or both) may not be able to withstand the heat caused by constant duty. Both should be cheap to acquire for a test...[EDIT: That assumes the board itself runs off 5V generated SEPARATELY from the incoming 18VDC -- basically two power supplies on the board, one for low-amperage 5VDC and one for the high-amperage 12VDC used by the gate and battery charger.]

BTW, to stop future blowouts, you might want to think about a fairly simple timer circuit that opens up the motor circuit if the motor runs continuously for 30 seconds or so (double or triple the normal run time). Having that timer latch until reset would be help you find the cause of the problem, too.

[RED-85-Z51]

I think you got a bad long or short caterpillar module on the right side there....

[Kevin_73]

Well, I don't know about the other board, but the fault of the board in your picture is pretty obvious -- F1 and F2 are missing.

j/k


You said the motor is 12VDC -- does it have a separate power supply that's switched by this logic board? If so, I wouldn't be so certain of your failure mode -- the board should only have motor current running through the relay contacts.

If the board does provide current for the gate motor, I'd suspect either the big capacitor or the voltage regulator chip. Either (or both) may not be able to withstand the heat caused by constant duty. Both should be cheap to acquire for a test...[EDIT: That assumes the board itself runs off 5V generated SEPARATELY from the incoming 18VDC]

BTW, to stop future blowouts, you might want to think about a fairly simple timer circuit that opens up the motor circuit if the motor runs continuously for 30 seconds or so (double or triple the normal run time). Having that timer latch until reset would be help you find the cause of the problem, too.


The board does provide current to the motor. It switches positive/negative for open/close, and shuts off when the limit switch is tripped.
I think the primary power for the board (and motor) is the 12V battery, but it will still run when only powered by the 18VAC source as well.

[Kevin_73]

Thinking about it a little more, even if the limit switch doesn't operate correctly, the obstruction circuit should not allow the gate to stay closed if operating properly.

You have any lightning lately?

I was out of town, but I think Liz said there was a storm that day, but the gate was working after the storm had passed and failed later when the weather was clear.
There probably were high winds that day. The gate could be pushed out of alignment with the catch pole if the wind is really strong, but that usually just causes the the F1 fuse to blow. It used to do this very easily, but I made some changes :smash: to the catch pole and it hasn't been an issue since unless the wind is extremely high.

[onedef92]

I was out of town, but I think Liz said there was a storm that day, but the gate was working after the storm had passed and failed later when the weather was clear.
There probably were high winds that day. The gate could be pushed out of alignment with the catch pole if the wind is really strong, but that usually just causes the the F1 fuse to blow. It used to do this very easily, but I made some changes :hammer: to the catch pole and it hasn't been an issue since unless the wind is extremely high.

Sounds plausible. :yesnod:

[Kevin_73]

I guess I could try connecting the motor to the secondary gate circuit, then flip the dip switch to dual gate. It looks like the primary and secondary circuits are identical, so maybe the secondary can operate independently. If the opener works that way it would tell me that the problem is isolated to the power switching for the primary operator circuit. If it doesn't work, I would assume that the problem is in the "logic" part of the board between the relays and the receiver. :confused5::confused5::confused5:

[Brett K]

Why can't you just train the dogs to open and close the gate?

[CertInsaneC5]

Why can't you just train the dogs to open and close the gate?

Now that's the best suggestion I've heard yet? :lol:
Almost sounds like you have a limit switch out of adjustment. Check the input terminals with the meter on the gate closed switch and check to see if you get conductivity when the gate goes from open to closed.

[Kevin_73]

Why can't you just train the dogs to open and close the gate?

I've been trying to train them to run the vacuum for years. If they ever get that one figured out we will start working on the gate thing. :seasix:

[ZipZap]

The board does provide current to the motor. It switches positive/negative for open/close, and shuts off when the limit switch is tripped.
I think the primary power for the board (and motor) is the 12V battery, but it will still run when only powered by the 18VAC source as well.

Wow. How big (Amperage) is the 18v source? That big capacitor must be what enables the start-up current for operation in that case.

[ZipZap]

I guess I could try connecting the motor to the secondary gate circuit, then flip the dip switch to dual gate. It looks like the primary and secondary circuits are identical, so maybe the secondary can operate independently. If the opener works that way it would tell me that the problem is isolated to the power switching for the primary operator circuit. If it doesn't work, I would assume that the problem is in the "logic" part of the board between the relays and the receiver. :confused5::confused5::confused5:

I don't have the schematic, but the terminals on the board lead me to believe you are correct.

[Kevin_73]

Wow. How big (Amperage) is the 18v source? That big capacitor must be what enables the start-up current for operation in that case.

It is just a small transformer that plugs into a 120V wall socket. I don't know the specs, but I doubt it is more than 3 or 4 amps.

I don't have the schematic, but the terminals on the board lead me to believe you are correct.

Well, it didn't work.
I'm thinking of ordering all of the different IC's (Caterpillars as Red calls them) and replacing them one at a time. Do you think that is possible, or do they have to be programed before installation?

I know the NVRAM chip must be programed, but I am not sure about the other IC's.

[CertInsaneC5]

It is just a small transformer that plugs into a 120V wall socket. I don't know the specs, but I doubt it is more than 3 or 4 amps.



Well, it didn't work.
I'm thinking of ordering all of the different IC's (Caterpillars as Red calls them) and replacing them one at a time. Do you think that is possible, or do they have to be programed before installation?

I know the NVRAM chip must be programed, but I am not sure about the other IC's.


Only the NV ram chip gets a program. :cert:

[Milton Fox]

This method may not be as easy as the set up you currently have in place, but you have extra cars laying around and no dogs need to be trained.

Cliffs: Someone stole some firewood. He made a gate out of a late model dirt tracker.

Bonus: truck burn out at end!

Lacks pics of wifey!

The redneck gate system.mp4 - YouTube

[CertInsaneC5]

Lacks pics of wifey!

Thinking that's probably a good thing. :lol: