[quote="ahmad_abdulghany
Yes, please, upload schematic of my monitor...
Also what if i found heater voltage greater or less than 6.3V ??
And what let you sure that the problem is in heater voltage specifically??
Thanks for help,
Ahmad,[/quote]
hello Ahmad
here's the complete service manual for ur monitor and it has a good service information that will help u repair ur monitor .
well, supposed to find the heater voltage less that 6.3V not more that 6.3V and that's the reason why the brightness is dim and in this case u have to check the supply rail to the heaters and may be u will need to replace the electrolytic caps on this rail , i have also attached a pic for the components that mostly responsible for causing that and hope it'll help u solving this problem.
about ur second question , i'm not sure that the problem is in heater voltage specifically , but this is the first thing we check before going further, may be u have a video output problem , may be u have to change some caps or a resistor that goes high in value or leaky transistor or diode , it'll be easier to have the problem here rather than checking the video output circuit.
i hope it'll be solved soon
Kind Regards