No Power On - NEC MultiSync 20WGX2 Series Service Manual

10. Power Board - No Power ON
Check power cord (P801), signal cable, P802,
Check pin 1 of T806 have same pulse or not.
Check peak voltage of R840 triangle pulse is up to
Check T806, D817, C845, C857 have same short
Check output voltage +5V is right or not
OK
P803 are connected
right or not.
OK
Check C801 is about DC140V-330V or not.
OK
Check C853 is over 16V or not.
OK
Check pin 8 of I808 have same pulse or not.
OK
OK
1.5 volt or not.
OK
circuit, or the output +5V is over load
OK
Check feedback circuit around I807 and
the other component and repair them.
NG It is not power board problem.
Connect it right.
NG
NG
Check F801, D802, P801 and repair them
Check D813, L810, I808, C853, ZD802
NG
and repair them.
Check peripheral component of I801 and
NG
repair them.
NG
Check Q802, R840 and repair them.
Check peak voltage of R840 triangle
NG
pulse is up to 0.85 volt or not.
NG Repair them.
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