Question LG 43UN700-B Monitor problem

[spike3333]

Hello,

I have a two year old 43UN700-B Monitor that I have two computers connected to. One via Displayport and the other through one of the HDMI ports. Recently, the computer connected via the HDMI stopped displaying. I connected it to all the HDMI ports and the USB-C port with no display. I hooked to the one Displayport and it worked. Then even the Displayport started taking a long time to be recognized. It would eventually come on but it took awhile. Assuming it was a bad motherboard, I ordered a EAX69012401 PCB. It was a used unit reclaimed from another monitor. I swapped the eBay unit in and immediate could see that it was also bad as it had half the screen was black. I did go ahead and try the HDMI and Displayport on the eBay unit and it appeared to show the same behavior as the original; HDMI and USB-C don't work, Displayport works after a slow response. I put the original back in and I am returning the eBay unit. My question is, could this behavior be power supply related (or something else)? Are there any tests I do to troubleshoot it further.

Thanks,

​

 

[LinuxDevice]

I've had several monitors fail which were all due to the power supply. Replacing the power supply gave each about another year of life. Note that these were internal power supplies, not the type with external "brick" supplies. Yes, power supply failure (if internal to the monitor) is high on the list of causes.

 

[spike3333]

I've had several monitors fail which were all due to the power supply. Replacing the power supply gave each about another year of life. Note that these were internal power supplies, not the type with external "brick" supplies. Yes, power supply failure (if internal to the monitor) is high on the list of causes.

Thanks for your reply. I found a power supply on eBay for $30 that I will try.

 

[LinuxDevice]

Thanks for your reply. I found a power supply on eBay for $30 that I will try.

I assume this will probably work. If it does work, then you might examine any electrolytic capacitors on the failed PSU. I would bet at least one of them is "bulging". If this is the case, then replacement capacitors might fix the old supply (perhaps you will need a backup to the replacement; electrolytics have a limited lifetime even when not used).