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POWER-BLOCK check
**Note : the Waveform of U304 pin 2 can determined the power situation
1. stable rectangle waveform with equal duty, freq around 150K-158KHz
that means all power of this interface board is in normal operation
,and all status of 5V & 3.3V is working well
2. unstable or uneven rectangle waveform without same duty, that means ABNORMAL operation was
happened, check 3.3V or 5V ,if short-circuit or bad component
3. rectangle waveform with large spike & harmonic pulse on front side , means all 3.3v is no load, U200
Gmzan1 was shut-down, and only U302 MCU still working , that means the monitor is in power saving
status , all power system is working well .
OK
Check U304 pin 2 is a stable rectangle wave?
Around 150k-158kHz stable rectangle wave
with equal duty without any spike or harmonic
pulse?
OK
NG, with
harmonic
p
ulse
Check U304 pin 2 is a unstable rectangle wave ?
The interface board power is good
Measure input power at U304 LM2596 pin 1=
12V ?
Check ADAPTER and connector if loose?
NG
NG
Check all 3.3V & 5V power, there is
short circuit or bad component was
happened
OK
,
unstable wave
The interface board is in power-
saving state, press power key to wake
up & check your signal input