Monitor Mitsubishi Diamond Scan 90e

[Markus Ryll]

Hello
I own a Mitsubishi Diamond Scan 90e, Modell: FFT9905SKHFW , seams to be
manufactured by Delta Electronics, Boards are marked with DB-995.
Some days ago the monitor didnt wake up from standby, a sync signal is
detected ( LED is green), but no picture, no OSD too. It looks like the HV
is there, degaus works too.

Does anybody know where to find a Service Manual for this type ?
Maybe the same chassis is buit into monitors from other manufactors, any
idea ?

Thank you for any help.

Markus

 

[John Gill]

Markus:
I would do the following:
1. Can you see the heater coils glowing at the end of the picture tube:
If not, Check the heater voltage on the CRT socket. It should be
about 6.3 volts DC. You will probably have the remove (unsolder)
the metal shield on the CRT neck board to do this.
2. If you have good heater voltage, check the G1 voltage on the socket.
Normal is about -20 to -60 VDC (Im not sure if this applies to the
DiamondTron tubes). If too negative (over -100VDC), tube is cutoff
and something is wrong in the circuit.
Hope this helps...
John