Prima PS-42T8 Service Manual page 23

POWER_ON/OFF of socket CN802 of the power supply board;
Solder point
and then push the slide switch SW2001 on the logic board to the internal modes (1, 3 up and 2, 4
down) from external modes (1, 2, 4 up and 3down).
SW2001
Switch the power on and see if the screen is lit. If the screen can give a normal and completely
white field signal, then the problem lies in our main board or video frequency processing board,
which will be dealt with separately.
d. If the screen is not lit, then first replace the power supply board to see if the problem is solved.
e. If the problem remains after the power supply board is replaced, then the problem lies in the
screen, replace the entire screen for treatment.
2.2 There appears on the screen a line or several unlit lines.
Check if the socket between Y driving board and Y BUFFER is plugged well. If not, plug it well. If
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