This problem is real and my LCD branded Deekbot off eBay has same issue.
I think replacing bipolar transistor with FET is the cleanest solution, but I don't have suitable FET around and I'm not looking to procure it.
I hate to take LCD out of the shield to reach transistor or resistor and my hands too shaky to cut trace and solder diode, and I hate to look for additional parts like shottky ot germanium diode, but I can do two other things that do not require additional parts:
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Pluck pull-up resistor from underneath LCD and run backlight control D10 as INPUT only. If you really up to it you may put 100K resistor from D10 to ground to prevent base from floating, but I don't think it's necessary.
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Pluck transistor out from underneath LCD and connect D10 directly to LCDs pin 16. Resistor is irrelevant. D10must be an output, but control will be inverted - full bright will be 0 and dim 255. Outputs are plenty strong to drive LED directly.
These are two separate options, not two steps for same one!
Use something like small watch screwdriver to pluck part of your choice. If trace start delaminating - just cut it with same screwdriver.
I think these fixes are easier than others.
I just did second option - works as expected. Took 20 seconds + iron heating time. See attached pictures. Second picture is half -plucked transistor standing on it's hind (BE) legs before final termination.
Cheers y'all!
