X24 with backlight but no LCD video

[ThinkDad]

My X24 has no LCD video. The problem developed suddenly. It worked normally one eveing, ...the next day no video on the LCD. External video works fine. The backlight doesn't seem to be a problem because I can see the backlight increasing or decreasing in brightness as I adjust the brighness settings using the keyboard.

I have tried reseating the ribbon cables with no effect.

From other postings it seems that bad LCDs don't usually just drop dead. I believe that the inverter powers the backlight, not the LCD. Is that right?

Any help would be appreciated.

[kodell]

The inverter sounds like it's working.

It's either a bad lcd, a bad cable or a bad motherboard. The lcd panel itself might be fine, but there are some active components - buffers/drivers - on the back of the panel that can fail. There are also some components that are on the motherboard that can fail and yet you would still have external video.

(Take any of this with a grain of salt, since I have no specific experience with the x24. My seat of the pants guess would be a fairly low probabilty of the problem being the cable & then equally likely to be either the motherboard or the LCD).

If it were me I would start by putting a scope on the signals coming off the LCD cable & try to see if the problem is on the cable/motherboard side or the LCD side. The alternative would be to replace pieces & hope you get lucky.

Someone is selling refurbished x24 lcd panels on ebay for around $90/shipped if it turns out to be the LCD.