PROBLEM FIXED GTO gate opener blue and green boards

[Carl E]

Hello, I'm about to pull out the rest of my hair.
Does anyone have a schematic or experience fixing GTO gate control boards ? I have 3 bad boards that I would like to fix. The boards are  green or blue, dual gate opener. The only marking on the board is MN030311 and  E244058 2D. Any help or suggestions would be appreciated.
PROBLEM FIXED.  Bench  Power supply issue,  Once supply issue fixed all boards work. Thank you to all who provided support.
 

[m k]

Shouldn't be overly complicated construction.
Maybe few photos would help.

[bill_c]

Had problems with one that would start beeping when starting to close (or maybe open), turned out to be a low quality limit switch in the actuator.  The control board doesn't tolerate both the NC and NO contacts being open at the same time.  I made a little buffer between actuator wiring and main board to latch the last known state and no more problems.  I had previously replaced the limit switch board in the actuator but that only worked for a month before having the same problem. The buffer has been working for a few years without a single failure.

[Carl E]

Thank you for the reply.  The arm that has the limit switch has been tested with another controller board and is good. When the signal to open or close is sent to the control board, I see a spike on the motor voltage that is 12v but is only a few milliseconds in duration. Although I think I understand what the board does, its almost impossible to troubleshoot without a schematic. I've attached a pic of the board. If anyone has repaired or can shed some light on how to fix the board, it is certainly appreciated. On average, I have to repair or replace some part of the gate opener every 6 months.

[m k]

So gate motor connectors are under a sticker.

U11 and U12 seem to be altered.
Is the corner of topmost relay from that situation also?

Info sticker beside the fuse is also covering things but maybe we can agree that BAT- goes to upper legs of both FETs.
When gate is operating the voltage between BAT- and FET heat sink is low, you can test that.
If those FETs are constantly burning their cooling may be insufficient or maybe components them selves can't stand the needed energy.

A component beside J5 text is also altered, maybe it's a protection diode, against relay coil kickback maybe.
If so and it's constantly burning it's too weak.

If missing limit switch is killing the controller then design is not very good since overcurrent is not dealt as it should.

If you have removed the square PLCC package chip without a proper tool, as seems to be the case, don't do it again, the socket corner has a tendency to crack if the chip is janked up against it.

[Carl E]

Hi,
I apologize for the crappy pic. I've removed the stickers and re posted the pic. The gate arm is connected to the master input. The arm contains the limit switch, IR emitter and receiver which count the motor revolutions. U11 and U12 legs were lifted to test the mosfets and resoldered enough to make contact. Not the best solder job, I agree, but it works. Same situation for the diode near J5 as it is across the relay coil K1 and measured short when in circuit.
Using a scope:
I have 1 good  board for comparison and tested 2 arms that work with the good board: On the bad boards I found that the mosfets are working, a small pulse  on the  U11 pin connected to the 10K resistor results in the 12V pulse on the tab and red motor terminal on the master input. I also found the the IR led AND the limit switch is being strobed and is not ÖN" as I originally thought.
Side note:left side of the board: Fuses are good, 5 V is present, battery charging circuit is good. the 2 relays, K1 and K2 are configured to switch polarity to the motor. Battery is at 12.8V
I'm having a hard time understanding how two boards are failing with the same symptoms, what am I missing?

[m k]

What black is showing when Red is pulsing?
Can you change the direction?

Anyway, U11 and U12 as power PWMs then and no common positive since J5 and J21 are 2 pins only.

But it's a double arm board, so the other side(U12 K3 K4) should be good.

The connection seems to go so that U11 or U12 is pulsing and shorting one relay contact to BAT- when BAT+ is connected through SWITCH to other relay contact.
Means that only when parallel relays are the opposite Red and Black can also be opposite and the arm operative.

[Carl E]

The switch supplies 12V to the board for 5v and to the NO contact of both relays. The NC contact of both relays is connected to the tab of U11 which connects to ground when either relay is energized .  When K2 relay is energized, the 12v + is supplied to the red motor lead. If K1 relay is energized, the 12V+ is supplied to the black motor lead, reversing the motor direction. For whatever reason, it appears that when either relay is energized, so is U11.
I think at this point, I need to chase down why I dont see pulses on the white, blue and brown connections.
UGHHHH !!

[m k]

If Red or Black is motor positive, where is negative?

[Carl E]

The negative is thru the relay that is not energized and thru U11 see attached.

[m k]

Yes.

You said earlier that U11 is pulsing, so you know that BAT+ is connected somehow.
You also said that you see a voltage dip, so there's also a reasonable load present.

If one relay is stuck to BAT+ you see U11 pulsing all the time but only one direction is actually operational.
But then welded relay contact must also include some resistance or FET or fuse will blow.
If one relay is stuck to motor side that relay can't pass BAT+ and that direction of motor connector is silent.

You can also start from that voltage dip.
Since U11 is stepping you should see the difference by marking the outer tip of the arm, even if it is moving only one step.
If controller is expecting feedback after every step it can stop trying without a feedback but then pulsing U11 should also stop.
So pulsing U11 indicates that the controller tries to move the arm at least a bit longer.
If dipping voltage is just a moment it's possible that relay contact is damaged and can't pass the current.
Though carbon should conduct better when warmed, so something else than carbonizing.

But this or that, if U11 is pulsing the arm should move.
You have many relays to compare, finding a difference should be pretty easy.

Was the broken diode measured off the circuit, was it multimeter beep style measurement?
If so then was the reading 0 or something more?

Are those diode pairs beside J5 and J21 connected like parallel to coils in your latest picture?
In earlier PCB picture those diodes seem to be connected to Red and Black.

Keep also in mind that it's outside and water do tricks, like drops that are gone when you are watching.
If lightning strike has happened you should see it, it's possibly a small and "shiny" color difference, but should be intuitive.

[m k]

One other thing, the motor, are there different type configurations?
Maybe your controller is electrically sound but its configuration has changed.

Next thing, stall force.
Maybe its value has changed to so low that it's stalling all the time.

Then limit, maybe its memory value has changed so that it's limiting all the time.

Do you have any info of those DIP switches?
Dual mode can be simply yes or no but there are 4 switches.

[Carl E]

hi M K
Thank you for your inputs on this problem.
The dip switches control soft close, push/pull, time delay,buzzer, etc. The strange thing is I have two controller boards that have the same problem. Both boards worked last year.
I am going to take a break for a few weeks from this problem (sometimes you need to walk away and get a fresh start). I have not given up yet, (never give up ), this is a great learning experience.

[coromonadalix]

if the mcu are in a socket, sometimes it help to put them out and put them back,  had strange bugs because of the oxydation ....    but you need to be very careful, you may crack the socket, you have dedicated pullers for that

[m k]

I am going to take a break for a few weeks from this problem (sometimes you need to walk away and get a fresh start). I have not given up yet, (never give up ), this is a great learning experience.

Yes, all counts.
It's very possible that your thinking is going in circles and maybe even shrinking ones.
You'll find it out afterwards, as how fast you think how simple it finally was.

Your exact motor is still unknown.
If its end has some electronics, other than those feedbacks, you can start thinking those controller outputting pulses differently, after checking how the good controller is operating.

There are practically three ways the controller can order the other end.
First is simple DC voltage, there motor end does necessary modifications for movements, this is also a type where motor movement and its feedback are sort of isolated.
So here controller put out a voltage and read from feedbacks what is actually happening.
Second is where DC voltage is pulsing, there motor has less control of what happens and controller can expect some feedbacks after every pulse.
Third way is where controller is actually a second controller and first controller is inside a motor.
So here the external controller is sort of ordering the internal controller to do its job.
There a pulse can include many things but so can feedback, so different feedbacks can be combined to one signal.
It's also a way where external controller doesn't need any power outputs.

So since your system is clearly outputting power only first and second ways are probable.
Checking the good one will also instantly reveal how the thing actually is.

Keep also in mind that you may have contact problems and initial situations.
Maybe your motor is seeing a low voltage and goes to safe mode.
Feedbacks have four wires, Green is possibly Common, if so then one wire can go out and one come back in.

You can possibly also check how the power pulse does compared to how it should.
If 12V part is shorter than with the good controller you can expect that there is a some sort of a safe mode.
But controller seems to be without any current sensing.
If current sensing is not there the motor can still has it, but there are no dedicated feedback so it must be combined.
Tachometer is most likely all by itself but limit switch wires can have multiple meanings.

There are also two connected relays, assumed operation is so that their states are opposite, that's also how I understand your drawing.
So one relay is putting BAT+ out and other one is connecting BAT- through U11.
So if J5 doesn't have U11 thing the relay is stuck or some connection broken somehow.
That is not electrically bad since it's the same as the other relay or nothing, but then motor obviously can't move.

Chips,
Zilog on low left of the picture seems to be a radio thingy.
Y3 and resistors around U14 indicate it's an MCU, maybe Zilog Z8.
Based on those U7 is probably also Zilog, something slow, maybe Z8 also.
What type is a possible switcher U2?

Some hazy parts.
Is there only one limit switch for two arms, are you connecting both arms through the same connector?
Is third bad board behaving differently than other two bad ones?

[fzabkar]

The FCC database may have some documents:

https://fccid.io/I6H

For example, this GTO gate opener has schematics:

https://fccid.io/I6HGTOFM200202

[m k]

Usage of relays and FETs are clearly still the old way.
Earlier broken diode is offering one cause, not very small spike.

[Carl E]

Thank you. I just logged in after a long break. I will pursue the links to see if the schematics can be found. UPDATE:
Schematics found....yahooooo! Not for the board version I have, but close enough to verify how these boards work. The mosfet is used to control the ground to the motor to stop it when the correct count from the encoder is reached.  The link to the FCC website is genuis Fzabkar !!