PCB Help?

[oznovice]

Hi experts
I'm a novice with electronics and was hoping someone here at an idea of how to fix this issue I am having with a 24V (battery powered - solar charged) gate motor control board. It seems to work more at night (so no power charging the batteries) and randomly during the day, unless it's hot/humid, then it just doesn't work.

I will post a pic of the unit and the board diagram from the manual if that helps.

The model is:
ISC800DC Sliding Gate Opener

So I have troubleshooted the following

Confirmed 26V volts at the board from the batteries.

Confirmed the remote is working, by manually checking Relay 1 (opening the gate) works. I originally thought it was the relay not working, so I opened the top of Relay 1 (see pic) and manually actuated it while pressing the remote and the gate ran the Open Cycle. Without manually moving the contacts on the Relay, it doesn't run power to the motor. When the unit started playing up originally, a flick with the finger (tap) on the pcb outer cover while pressing the remote would get the gate to open.

Confirmed no power (obviously) on the PCB to the motor connector when the unit is playing up.

When the unit is playing up and not working with the remote, I have noticed this module (I believe it's a Voltage Limiter??) gets hot. I dont have an accurate temp on it, but it's almost too hot to touch.

I have installed switches to turn off solar charge to the batteries (so no power to the PWM controller from the solar panels but pwm still connected to batteries, so power available at the Load output of the PWM), and I have a switch to turn off power to the Control Board (which then allows that Module (voltage limiter) to cool down). Turning the power off to the PCB for a while, used to correct the problem until that unit heated up again. The manual shows the Load output of the PWM connects to the PCB of the gate motor.

I have checked the rear of the PCB and see no burn outs and have resoldered/cleaned the solder points on the pcb that looked dull.

If it's a simple fix, I would just rather replace a module on the PCB rather than buying an entirely new 24V electric gate, as it seems buying another complete kit is about the same price as a new control board and a lot of work to replace the entire unit. It's about 7 years old.

I think it's not getting the signal to engage the relays to run power to the motor somewhere, but as mentioned, manually actuating a relay while pressing the remote does send power to the motor, so I think the remote sensor on the pcb is working correctly. So whatever is supposed to actuate the relays (open and close) I think could be causing the issue. Could it be an internal failsafe on the PCB, for heat/outside temp/humidity? This model gate opener uses Magnets to determine if the gate is open or closed. All LEDS are lit when the unit is fully opened or closed, so I thought that meant the PCB was reading the gate position correctly?

Is that small blue box a relay as well? (see pic).

I'm totally stumped. I have to replace relay 1 as I have opened the top, and was thinking of replacing the other, plus the Blue Box one (if that's a relay also). It just doesnt make a lot of sense to me that it works fine for a few days and nights, then wont work sometimes, even at night.

Any help you experts could offer would be much appreciated.

 

[Diver300]

Can you see what is written on the front of the component that gets hot?

 

[oznovice]

Diver300: Thanks for that info on the diode. So the grey part could mean it's a schottky diode?

 

[oznovice]

Diver300: Re: component that gets hot, I can't see it in the photo. After reading the replies, I looked up google, and it said those type of voltage regulators, it's normal for them to be 50C up to 90C so it could be just normal? I had the feeling it's a T220, but will check tomorrow.

 

[oznovice]

I have just seen Diver300's post #18. I do not agree that that diode is for back emf protection on the relay coils. It doed not need to be that large for that purpose as the relay coil only draws about 66 mA. Acording too the datasheet on the black relays the coil is 362 ohms.
Les.

Thanks for the link Les to the datasheet. Probably wiring in LED lights to check the relays might be a bit more advanced for me lol. The board does have LEDs for when the two black relays are triggered. I will check the wiring connectors on J10, and volts.

 

[Nigel Goodwin]

I have just seen Diver300's post #18. I do not agree that that diode is for back emf protection on the relay coils. It doed not need to be that large for that purpose as the relay coil only draws about 66 mA. Acording too the datasheet on the black relays the coil is 362 ohms.
Les.

What difference does a bigger diode make?, better too big a diode than too small a one - you generally use what diode you have.

 

[Diver300]

Diver300: Thanks for that info on the diode. So the grey part could mean it's a schottky diode?

No. On a diode you can only see the plastic housing. That tells you almost nothing about what is inside. The numbers written on it, the position in circuit and the electrical characteristics will tell you what sort of diode it is.

 

[Diver300]

Diver300: Re: component that gets hot, I can't see it in the photo. After reading the replies, I looked up google, and it said those type of voltage regulators, it's normal for them to be 50C up to 90C so it could be just normal? I had the feeling it's a T220, but will check tomorrow.

TO220 is the package size, which can be seen from the photos, but we need to know what is written (which won't be TO220) to know what component it is.

50 - 90°C could be normal. However, I got the impression that it got hot only when the board didn't work, which could indicate a problem, even if the problem is not directly related to the temperature.

Also, for it to generate heat as high as 50°C, that would indicated that quite a lot of power was being generated in the TO220 device. A gate opener would only use a tiny amount of power if the gates aren't being operated, or the battery life would be poor.

If you can tell us what conditions make the TO220 device hot, that might help.

 

[oznovice]

TO220 is the package size, which can be seen from the photos, but we need to know what is written (which won't be TO220) to know what component it is.

50 - 90°C could be normal. However, I got the impression that it got hot only when the board didn't work, which could indicate a problem, even if the problem is not directly related to the temperature.

Also, for it to generate heat as high as 50°C, that would indicated that quite a lot of power was being generated in the TO220 device. A gate opener would only use a tiny amount of power if the gates aren't being operated, or the battery life would be poor.

If you can tell us what conditions make the TO220 device hot, that might help.

Thanks Diver300: Here's a pic of the component. Bit hard to read. I can see, LM (9, or 3 is the first number after), GK0SS V6 620 e. After reading the replies and what I read online, heating up this module might be normal?? I checked all the pins and re tightened all wiring connectors. So I have rechecked everything, and when remote is pressed, the relays have sufficient power to run the gate, but, I have to manually actuate the relay while pressing the remote, and when I stop actuating the relay manually, the gate stops. Possibly not enough power to keep the relay in contact, or limit switch of thinking the gate is fully open/closed? I flipped pin 7 to On as well and set the VR3: Stall Force Adjustment to max (Stall Force - default is on but it was off).
I will order new relays next week anyway. I would have thought it's strange having a reasonably powerful magnet on the gate track for close or open, being so close to a pcb as well. Thanks for all the help guys

 

[rjenkinsgb]

LM3153?? That would be a switched-mode regulator or power controller.

https://www.ti.com/lit/ds/symlink/lm3153.pdf

As there are no inductors near it, I wonder if it is being used as a soft-start controller for the motor.

That brings in new possibilities - is the mechanical side stiff, so the motor is never starting & the direct power relay is only supposed to activate once the motor reaches a certain speed??

Or, again, the batteries have had it and cannot provide sufficient current to get the motor turning, so the soft start is never bypassed?

 

[oznovice]

LM3153?? That would be a switched-mode regulator or power controller.

https://www.ti.com/lit/ds/symlink/lm3153.pdf

As there are no inductors near it, I wonder if it is being used as a soft-start controller for the motor.

That brings in new possibilities - is the mechanical side stiff, so the motor is never starting & the direct power relay is only supposed to activate once the motor reaches a certain speed??

Or, again, the batteries have had it and cannot provide sufficient current to get the motor turning, so the soft start is never bypassed?

Thanks rjenkingsgb, I am not sure about the soft start controller. I found a place in australia that also sold a rebranded version of this gate opener kit. They have a much better manual with more pictures than the original I had. I am going to try and give them a call tomorrow. Strangely too, the only place I see a physical ground is from the ground wire on the magnetic limit switch (i think that is what it is called). In the manual it says this unit must be grounded. Would a bad earth cause these issues? Also most of these sliding gate kits now have photocells, not the magnets.

 

[Ian Rogers]

Nor am I.. Why would a PSU just drive relays .. There are several resistors next to said To220 device.

The pinout for a LM317 match but I can't see it being that unless the relays are not 24v types..