Unofficial Nextion/TJC User Forum

Accidental overvoltage - any repair suggestions?

I accidentally applied near 12v to the 5v input of my Nextion 4.3" enhanced… twice!
Yes I burned 2 screens… my buck regulator circuit puts out 5v most of the time, but occasionally puts out 12v… resulting in this damage.
Im back on a reliable 5v source now, and trying to repair my screens.
Both screens respond to serial messages, so something is working, but the display is dead.
I have checked U7, the linear regulator close to the power input.
It is still putting out 3.3v.

Can anyone suggest anything else I can try to repair these 2 screens?

Model number NX4827K043_011.

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Possible dead gpu. Check it

There is no GPU on this Nextion HMI. Just a LCD driver IC. But since the 3.3V are intact, I’d say it has survived.
I’d rather look into the backlight boost converter. But in general, with a minimum of self-esteem, your working time to diagnose and fix it will be more expensive than buying new and reliable stuff.

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I had the same fault and that was it, I also received voltage but the ic got very hot

In the end, it was one of the backlight LEDs was burned, disabling all of them. My assistant was able to patch it by shorting out the bad led, and the rest were still ok. One part of the screen is slightly dimmer than the rest, so we cant use it for production, but we will keep it for test rigs.

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