Dead Mitsubishi 1998e Monitor
 

The chassis has "Acer ELECW 2 94v-0" stamped on it.

Power led lights up.
It has HV but no picture.
The heater looks a bit dim compared to other models ive worked on.
Heater voltage is 5.5v and resistance at the pins is 5.3ohms.
The other voltages at the crt pins are,
G1 -183v
G2 166v
R 39v.
G 33v.
B 37v.

Ive checked esr on all the caps, and tested big resistors, HOT, diodes,
transistors, dry joints etc.

Your G1 voltage is way too negative which biased off the picture tube.
I would trace the circuit down and check the parts. There is usually
some way to feed a variable positive adjustment voltage into the G1
circuit. This may be defective.

I would expect the G1 to be about -40 to -60 volts in normal operation.
Try connecting a variable resistor box to the G1 pin on the neck board
and ground. Then starting at the highest resistance, slowly reduce the
resistance and see if the picture comes back when you reduce the G1
voltage.

The G2 voltage seems low. This is an high-impedence circuit and your
meter may be loading it down. I use an 100 to 1 probe on my meter when
I check G2. I would expect 300 to 450 volts.

Video cathode voltages also seem low. I would expect 50 to 70 volts
here. Is your B+ voltage to the CRT neck board OK ?

Hope this helps.
John

wrote:
Your G1 voltage is way too negative which biased off the picture tube.
I would trace the circuit down and check the parts. There is usually
some way to feed a variable positive adjustment voltage into the G1
circuit. This may be defective.

I would expect the G1 to be about -40 to -60 volts in normal operation.
Try connecting a variable resistor box to the G1 pin on the neck board
and ground. Then starting at the highest resistance, slowly reduce the
resistance and see if the picture comes back when you reduce the G1
voltage.

The G2 voltage seems low. This is an high-impedence circuit and your
meter may be loading it down. I use an 100 to 1 probe on my meter when
I check G2. I would expect 300 to 450 volts.

Video cathode voltages also seem low. I would expect 50 to 70 volts
here. Is your B+ voltage to the CRT neck board OK ?

Hope this helps.
John



i turned up the screen control on the flyback and got a picture.
i now have a 10mm vertical line on the screen.
G1 is still the same but G2 has gone up to 242v.
ill do some more testing tomorrow.