@retiredcaps
If there would be something wrong with the input protection, what would be the symptoms for the device? I would assume that the device should boot up normally, but one could not make any measurements. My unit doesn’t display anything on the LCD, but most of the voltages on test points seem to be similar to those listed by @purpose and @frenky. Can I assume that any potential issue with the input protection does not have anything to do with blank LCD?
I’ve just measured voltages as @sacral described in post #39 and below are those, for which I got different readings.
@sacral
My unit powers down after few minutes and so the voltages are changing. Maybe some of the measurements you’ve made were made after the “sleep”? I’m just asking. It is probably different because mine is broken

Here are deviations from @sacral list:
TP 1: 0.005
TP 3: 4.96
TP 9: 2.28
TP 16: 2.91
TP 18: 1.81
TP 32: 3.07
TP 33: 3.07
TP 34: varies in a mV range
TP 37 0.057
How can I test the LCD? Anybody can give me some simple guiding for this task, so I could eliminate the faulty LCD, please?