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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