The LG Flashing Monitor

 

 

 

 

 

 

This LG monitor is used in the office section of my electronics lab & has worked well since it was bought brand new many years ago. However, it started to take longer to boot up in the mornings & during that time would occasionally flash random colours.

Of course, when it is your own monitor, it gets pushed to the back of the line & is only repaired when you are frustrated, combined with the possibility of impending failure or actual total failure. In this case I decided to prioritise the repair before I had no 2nd monitor on my desk.

After confirming that this was a repeatable problem, I decided it was time to pull apart the monitor and carry out the repair before it failed completely.

I naturally assumed that the stand and mounting bracket would have to be removed, but after some time, realised that the screen and all the electronics were accessed by removing the front frame around the screen. After unsnapping the bezel, the screen, the power supply and other circuit boards basically fell out onto the bench.  They were just retained by the plastic frame itself, with no screws to hold it in place.

As I removed the various connectors, I noticed a very dark patch on the power supply circuit board. I naturally assumed that I had found the source of the monitor issues.

After doing some basic tests of components in the area, I decided to check some of the swollen capacitors. 

After testing them with my ESR meter, some were confirmed to be out of range. I replaced all that I had in stock with higher voltage caps. The other remaining capacitors were well within range.

Once this task was done, it was time to turn my attention to the darkened patch & the possible component responsible.

This IC was the LED driver with an operating temperature range of -40 – 120˚.

I operated the now repaired monitor for over 20 minutes, with no screen failure at all and most importantly, the LED driver ran at a maximum temperature of 96˚. I must conclude then, that the faulty capacitors had been slightly shorted inside, creating a higher current to the LED driver, causing it to overheat.

It has been well over a year since I did this repair with no issues to report.

If you are interested in this repair, you can see a video on my channel following the link below:

This article was prepared for you by Mark Rabone from Australia.

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Note: You can check out his previous repair article on BA Falcon Interior Command Centre No Power Repaired

 

8 Comments

1. 

   Parasuraman S

   June 22, 2024 at 2:52 pm

   Hi! A much-awaited article from you, dear! It was a good fix and thanks for sharing!

   Likes(1)Dislikes(0)

   Reply
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     Mark

     June 22, 2024 at 9:47 pm

     Thanks Parasuraman, it has been a long time between articles. I write for other companies as well, but I always look forward to writing for Jestine. It's always great to catch up with so many talented electronic masters.

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     Reply
2. 

   Waleed Rishmawi

   June 22, 2024 at 3:01 pm

   good job on the repair. yes capacitors would do such issues in many electronic devices and good thing we still have replacements for it. any way, thanks for sharing and have a blessed day

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   Reply
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     Mark

     June 22, 2024 at 9:48 pm

     Thanks Waleed. The swollen caps will create all sorts of weird problems every time.

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     Reply
3. 

   Albert van Bemmelen

   June 22, 2024 at 3:21 pm

   Well done Mark! It is always a good thing to keep all our devices in good working order. And those often very dark looking printed circuits luckily normally never turn in conducting short circuiting carbon area's.

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   Reply
4. 

   Mark

   June 22, 2024 at 9:50 pm

   Hey Albert, I was sure that the LED driver IC surely would have been cooked with such discolouration, but after checking the temperature and it working for well over a year now, it looks like I got to it in time.

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   Reply
5. 

   Imoudu.O

   June 24, 2024 at 5:23 am

   Wow! i did enjoy ur video clip, all i want to do now is to subscribe to ur link, pls tell me how to do that, thanks

   Likes(0)Dislikes(0)

   Reply
6. 

   Yogesh Panchal

   June 24, 2024 at 8:03 pm

   Good Fix! Mark

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   Reply

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