The broken PCB is the small one on the front of the A/C which accepts input from the infrared remote control.
It also has a physical power button on this PCB which turns the unit on and off with no options.
From the display output on the LED number display on this PCB, it shows the same two lines that would show up if I pushed the physical power button on the PCB.
So my guess is that this manual on/off from the physical button on the PCB is what is getting triggered.
In the middle of the day or the middle of the night, it will act up with a lot of loud beeps and the aircon turning on and off and on and off very fast and it won't stop until I flip the breaker to cut the power.
Then sometimes it will go for several weeks or months with no problem, then it will start again.
I have tried cleaning the contacts of the connectors and it seemed to stop the problem temporarily but it always comes back and it might have only been a coincidence that it worked.
I attached photos of the front and back of the PCB in hopes someone might spot something that might help me fix it.
I have limited electrical knowledge/experience, and I don't have a multimeter or a soldering iron so..... yeah.
Thank you.
(higher resolution photo of the board is here: https://www.yogile.com/koppelacpcb)

View attachment 217804

 

Hard to say from that view - need to reverse engineer the circuit to see how it works... can you give the part number for the IC (IC1), without that its going to be hard to figure (it might be a custom part though...).

 

I'm sorry I wasn't able to get the part number.
However, I have another clue to what might be causing the problem, not sure if it helps:
I noticed that after the problem occurred again, and I disconnected the PCB, I still felt a charge when my finger touched the wires on the back of the emergency on/off button or the "manual on/off from the physical button on the PCB" as I called it in my original post.
So I was wondering why I was getting small electric shock from that switch when no electrcity source was attached to it.
Maybe that's the problem?

 

IC1 looks like a TI chip, please identify or post a picture of the chip we can read. You may be getting a small zap from a capacitor. Doesn’t necessarily mean anything is wrong. Nothing looks physically damaged. I wonder if you have a bad/worn out switch.

 

@Irving @Wolframore Ok, I finally got what you mean, sorry:
Here it is, it's Texas Instruments:
2CA3YSK E4
SN74HC164N

 

While you’re focusing on the remote unit do you realize the fault could be on the main board?

 

@Irving @Wolframore Ok, I finally got what you mean, sorry:
Here it is, it's Texas Instruments:
2CA3YSK E4
SN74HC164N

View attachment 219333

That's an 8 bit shift register.. probably to drive the 7 segments.

 

While you’re focusing on the remote unit do you realize the fault could be on the main board?

It could be, but I live in SE Asia and we use A/C every night, and cannot afford right now to buy a new one, so I have been dealing with the problem by turning on the A/C, setting the temp with the remote, and then unplugging the PCB for the remote from the main board and leaving it disconnected thru the night until I want to turn it off the A/C in the morning, then I connect it again, use the remote to turn off the A/C, and shut off the breaker so that it doesn't randomly turn on and off during the day. The aircon runs fine while the remote PCB is disconnected and maintains the temp set before I disconnected it.

 

Do you have a TV near this unit? Stray infra red from another remote could trigger it, try putting something over the IR sensor to rule this out.

 

Do you have a TV near this unit? Stray infra red from another remote could trigger it, try putting something over the IR sensor to rule this out.

No tv or other infrared device, there is no chance of stray infrared triggering it.

 

Hello Mods, please remove this thread, I don't want it posted anymore. I received absolutely ZERO HELP from this forum.

Patience...
Keep in mind that this forum has contributors that cannot spend 100% of their time replying to every question.

From the looks of it, your circuit board doesn't have any complex circuitry on it. The integrated circuit that you gave us the part number for is simply used to properly display numbers on your seven segment LED display. All of the other devices are passive devices with minimal ability to cause your symptoms. There is no visible damage to the board.

Wolframore's suggestion about stray infrared is very plausible. There are stories of less than savory characters changing the channel on their neighbors televisions by beaming a compatible remote through the window. Weird but possible. That's why he made the suggestion. Have you purchased a new TV with a remote? New cable or satellite service? Any other item that might also use a remote.

Another suggestion to rule out stray infrared would be to cover the IR receiver, the black domed device next to the seven segment display, with thick cardboard after you have set the temperature. Note whether the symptoms persist afterwards.

Another possibility would be some electrical device that is creating enough stray signal so as to interfere with your AC control signals. Have you purchased any new appliances? Have your neighbors?

 

Please delete this thread.

 

Intermittent problems are horrible. Could be something cracked internally but your guess is good as any

 

Intermittent problems are horrible. Could be something cracked internally but your guess is good as any

Right. If my guess is as good as any, then please remove this thread. This is 3rd time I am asking.

 

shaggy77,
What's wrong with you?
You are getting FREE advice, given in good faith.
The suggestions are all good.
Looks like you joined the forum to ask for help.
Are you prepared to help others?

 

I was asked to post the part number of my IC1 chip, which I did and unkowingly also posted the exact chip ID. For all I know this can be a privacy breach and/or can be used for fraud to spoof another T1 chip.
Yes @twohats, I have nothing to contribute because I am not an electrician.
I also will not request anything from this forum again.

You have removed any option for me to delete my own posts, so I am requesting the mod to simply delete my thread.
Even if there is no threat of fraud or compromise privacy, I would like my thread removed.
But that is being refused. I never had a forum refuse to delete something which I requested to delete.
Nice.
View attachment 222554

 

Fear not. You haven't given us any information that compromises your privacy.

From the information that you've given us we can say that it's unlikely to be a problem with the board you've given us pictures of.

• From what I can understand, your LED's all display properly including the two digit seven segment display.
• Your IR receiver takes commands from your remote, so that is working.
• The fact that you feel a shock when touching the back of pushbutton doesn't tell us much. It's likely that there is just enough voltage potential across the terminals for you to feel it. It also sounds like the button still works. That's the important part.

Those are the functions of the board that you've shown. This means that the board is likely working properly and I wouldn't bother trying to replace it.

Going further, that board must connect to a control board and that's the next likely place for problems. Since you insist that it's not stray infrared, the next likely possibility is radiated electrical interference. Have you purchased any new appliances recently? Are there any other devices in your area that might cause problems. Is there anyone with a radio transmitter? Universal motors have brushes and are notorious sources of electrical interference. Do you or anyone near you have one that runs when the AC unit malfunctions?

 

@Lo_volt I appreciate your input, however, I don't think it's being caused by wireless interference or a problem in the main board because:
1) The problem only occurs when the small PCB i posted here is plugged in. I turned the A/C on and unplugged the small PCB and left it running for a long time on many occasions, and the problem does not occur. When the small PCB remains plugged in, the problem seems to recur within a day or two now (although previously, it could take weeks before it recurred).

2) The infrared receiver is very weak, it won't even accept signal from the remote control unless I am right up close to it and even then I still have to press it a few times.

3) None of the neighboring units have this problem and some use the same type of A/C.

4) I am not located in a high-tech area, even the 4G is hit or miss. People here are not the type to mess with lots of tech or universal motors or have lots of appliances. I, myself only have very minimal appliances and nothing that would interfere.

5) The problem occurs when the A/C is on and when it is off. Since this small PCB controls the power on/off of the A/C unit, it seems likely the main board would not be active and causing any problem when the A/C is powered off. Since the small PCB controls the on/off of the A/C and the problem itself is that it randomly turns on and off, it seems like the small board is the problem.

It's probably a faulty button on the small PCB. Even if the button works, it could still be faulty and activate when it isn't pushed, right? However, I don't have any tools to test it so I don't know.

I STILL would like this thread deleted. Why is that a problem? Please delete it.

 

Hello,

I have deleted the rude comments and tried to revert the deleted posts.
I have banned the user for being this rude.

Bertus

 

Just lock it