Firmware Issue In Mitsubishi LCD Monitor
This Mitsubishi LCD Monitor came in with the compliant of no power. Once I had confirmed that the Monitor was no power I opened the casing to check to start troubleshooting it.
Below is the photo that shows the Main board, Power supply, and Inverter board section.
When I check on the output voltage from the power supply it did showed 5 volt which means the power supply was working. One thing for sure was if all the memory ICs were getting the 5 volt and the front power LED still would not light up means the data in the IC could have been corrupted.
The easiest thing to do among all the memory ICs was to reprogram the EEprom IC first before go to Flash Rom and the MCU IC.
I took out the 24C02 EEprom IC and reprogramed it with new data since I got the original data from another similar working set.
Once programmed and powered On, the front power LED was lighted up and I could see the screen appeared (Windows). See the two photos below:
Conclusion- In this case, it was simple to troubleshoot because you already eliminated the power supply cause because it was supplying the 5 volt. So the concentration was on the memory ICs. You need a programmer to extract from a good memory IC and then rewrite or overwrite it in the corrupted EEprom IC. If you want to be an expert in LCD Monitor repair you can check out Jestine Yong’s ebook in LCD Monitor repair– Volume 1 ,2 and 3.
This article was prepared for you by Suranga Bandara who owns an Electronics repair shop in Anuradapura, Sri Lanka.
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https://jestineyong.com/power-blinks-in-lg-led-tv-repaired/
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Gary Gemmell
April 20, 2019 at 10:40 pm
What software and eeprom burner are you using Suranga?
Mihai
April 21, 2019 at 12:48 am
Hello, Suranga ! Good job, thank's for sharing !
Albert van Bemmelen
April 21, 2019 at 1:50 am
Programming Bios/firmware always is the best thing to do first which you did.
The RT809H is a great programmer for that, in both reading and re-writing/flashing of firmware. Although it is autoverifying and very fast I noticed that if we place Bios chips turned 180 degrees wrong in the RT809H socket, chips are still recognized and read but is followed by a screenmessage saying that there is a verify error at address 000000. (sadly the screen example of the programmer software program how to place in the chip is very tiny and almost impossible to see, so that mistake is easily made).
Today my programmer luckily fixed another firmware problem with a dead Asus P5KPL-AM SE motherboard that showed no video output and was useless until I re-programmed the sop8 25X80AV Winbond Bios chip with Bios version 0702. A diagnostic card inserted in the mainboard PCI slot showed a running clk signal and a post end code of 32. Which turned out being caused by a corrupt Bios chip. Which easily happens when the Asus mainboard apparently flashes unexpectedly its own firmware (every Asus mainboard is included with an EZflash utility and the EZflash program that is able to fix dead mainboards causing more problems instead of solving them) while a windows installation was started from a iso image on USB memory stick.
Albert van Bemmelen
April 24, 2019 at 4:39 am
Luckily it apparently is also possible to ZOOM-IN on the example picture on the left in the RT809H programmer window on how to place any chosen IC. In case of the mentioned Winbond 25X80 eeprom it shows pin 1 in the up to the left direction and pin 8 up to the right in the lowest position of the socket. (Furtest from the sockethandle on the upper left),
Robert Calk Jr.
April 21, 2019 at 2:57 am
Good job, Suranga!
Parasuraman Subramanian
April 21, 2019 at 6:29 am
Expert quick solution as usual! Well done!
Yogesh Panchal
April 22, 2019 at 3:51 pm
Excellent!!
Andre Gopee
April 23, 2019 at 11:23 pm
Great Job. I have a 55 Inch 3D Toshiba that has the same problem and I can get the firmware. I have a programmer but I need the firmware. The model of the TV is 55TL515U. Does anyone have this firmware that I can get or know where I can get it. Thank for the interesting article.
Devon Wilson
April 24, 2019 at 5:48 am
Great job. Thanks for sharing this information with us.
Bufford Moore
April 24, 2019 at 11:08 am
Interesting problem and repair, thanks for posting it. Hope you and all those around you are safe
Doğan
December 16, 2020 at 5:15 pm
You are a very good mechanic. You are telling very well. Greetings from Turkey...