greetings!!!
i am repairing a 15" AOC monitor, model: 5en, black chassis. Its first
symptoms was a ticking sound with no other action. I found a shorted MOSFET transistor (IRF634B) in the secondary side of the low voltage PSU. Tested other components in the PSU but they are ok. After replacing the transistor, it now turns on but the display becomes too big and it comes on and off accompanied by a clicking sound. I observed
that its the high voltage that comes on and off. Then after that cycle,
there's no raster anymore. But the frontpanel light is on and the control for screen adjustments responds when pressed. Can anyone give me suggestions on how to fix the problem?
an additional info to my previous post: after replacing the transistor.
it stopped ticking. i measured the b+ voltage (i based the voltage read
on a good monitor) and its seems ok. i connect the video cable to the video card, it attempts to display the
information but resulted to whining on/off and blinking of power led (green color).Then i noticed the high voltage come & go. i measured the
voltage during this phase. it rises and falls back to 90v. what am i missing? i think the problem only arises when it recieves signal from the video card.
thanks in advance,
regards,
ian b