Yes, both monitors were bought at the same time, and used roughly
equally. But one monitor started failing over 18 months ago, while
the other just started this month.
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OK, the contamination doesn't exists then ...
i'm sorry for your bad news.. i would to think to monitoring
the pow.supply outputs and then evaluate if is a power board problem and
which part of it, it is useful to know if want to buy an used or new board or
continue to repair . If i'm not wrong the 12v line powers the inverter that by the
video seems to work well, there is a 5v and nothing more or a 3,3v,
test them, you can also supply 5v from another p.s.u. to have a verify. If 5v is stable
there is maybe a transistor that powers the panel, it makes the on/off function
for st.by mode, i have i Benq with this failed. you can test it, or test the supply pin to the
panel, u need the datasheet of the panel for pinout, it is possible to make
a bypass of this to supply the panel like i did for test.