Envision EN9110, Service Manual

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19
PANEL-POWER CIRCUIT
INVERTER Control Relative Circuit
OSCILLATOR BLOCK
U600-DATA OUTPUT
OK, R202 have
Check R202 should have response from 0V to 5V
When we switch the power switch from off to on
Check the PPWR panel power relative circuit,
R201, R202, Q201, U203 (pin 5,6,7,8)
In normal operation, when LED =green, R223
Should =0 v,
If PPWR no-response when the power switch
Turn on and turn off, replace the U600-GM5020
NG
Measured the U203 pin 5,6,7,8= 5 V?
Replace U203 (Nmos, SI9953)
NG, no Voltage
OK
Replace INVERTER to new-one, and
Check the screen is normal??
Measured the inverter connector CN502
Pin 1,2=12V, pin 3 on/off control=5V (on)
YES, still no screen
Check the Bklt-On relative circuit, R520, Q503, R519,
In normal operation, when LED =green,
R520 Bklt-On should =0 v,
If Bklt-On no-response when the power switch turn on-off,
Replace the MCU
NG
OK, & Re-do white
OK
Measured X501 Oscillator output 24MhZ?
Replace Oscillator X501
NG, no transition
OK, has transition
Measured X600 Crystal output 24 KHz?
Replace Crystal X300
NG, no transition
OK
Measured DCLK, DHS, DVS, DEN (pin G20,
F20, F19, F18 from U600)
Is there have any transition?
Pclk around 47MHz to 57MHZ, PVS=60.09Hz,
PHS around 67 KHz?? (Refer to input
signal=640x480@60 Hz 31k, and LED is green)
Replace GM5020 (U600) or replace
main board
NG, no transition
OK
If Main Board being replace, please
do the DDC
–
content
reprogramming
Check U203 pin 1,3= 5V
Yes
Check U502 pin18
NG
NG