No Raster, Indicator Is Green - Compaq MV7540 Service Manual

6-3. No Raster, Indicator Is Green

Connect with signal and check the voltage of G1 is
between -25 and -65V.
Check the voltage is
at the normal range
Section1
YES
Check the brightness
control circuit as
Q705, R705.
If the indicator of functional key is normal when there's
no signal.
YES
Check the voltage is
about 0V
Section2
Check the voltage at base of
Q705 is normal.
Check MUTE circuit as
D420, IC101
NO
Check the voltage is
.
about -80v
Press the menu key and look if the
indicator is under control.
YES
NO
17
Check CPU control circuit
1. 5v power supply circuit
2. Rest circuit
3. oscillator
2
4.I C bus circuit.
NO
Check if it is high level
at pin16 of IC101.
YES
NO
Check the signal cable
HP MV7540