Envision EN7220 Service Manual page 29

2.PANEL POWER CIRCUIT
Check R624 should have response from 0V to 5V
When we switch the power switch from on to off
OK
Measured the Q601 pin 3= 5 V?
OK
3.INVERTER CONTROL RELATIVE CIRCUIT
Measured the inverter connector
CN201
Pin2 on/off control=5V (on)
Pin10 PWM signal control dim 0V-5V
Replace power board to new-one and check
the screen is normal?
OK
NG, no Voltage
OK
NG, still no screen
Check the PPWR panel power relative circuit,
NG
Q603, Q602(pin7,8)
In normal operation, when LED =green, R624
should =0 v,
Replace Q601 ( N-MOS, SI9933)
Check the Bklt-On relative circuit, R212, R205,
NG
In normal operation, when LED =green,
R212,R205 Bklt-On should =5 v,
If Bklt-On no-response when the power switch
turn on-off, Replace U401 MST8111
NG
Replace Power board
& Re-do white balance
29
EN7220 Service Manual
Yes