Picture on PSOne screen is very dim

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Hi everyone!

I have a PSOne Screen that powers up fine but the picture on the screen is very dim.

I can see video on the screen but there is no backlight, so I replaced that PSOne screen with another PSOne Screen same part just from a different unit (One I knew that works fine) and ... tada! ... same problem! screen powers up but no backlight.

I now know that both screens are fine the problem seems to be located on the PCB.

I have heard that the step up transformer located on top of the PCB is usually what causes this problem, like on most laptop screens but I'm not sure how to check the transformer on the PSOne PCB, is there a way to diagnose it?

I know the basics on how to use a multimeter, so you can help me out on where to put my probes.

Thanks in advance for any help.