Thinkpad A31p Backlight Outage

[Nycto]

Hey guys, I have a question regarding an A31p unit. The backlight is not displaying. The unit boots fine - I can make out the IBM logo on the display, and I can use it just fine when connected to an external monitor. My question is, more specifically, is there any way to isolate whether its the inverter or the back light, or perhaps even something else?

[Screamer]

Is your A31p's panel exhibiting any signs of a red tint across the entire screen upon start-up? Did you try to use the Fn+Home/Fn+End key combinations to check if the panel is acting up with the brightness hot-keys? If it does change its brightness level and flickers, it might be the display panel.

Shift your A31p's lid up and down and check if the panel's brightness changes. If it does, that means that the display cable is either loose or bad.

I have heard that inverters usually work or don't work at all. A dead inverter would most likely result in a display that does not show anything, not even the IBM boot-splash would show up if you powered up the affected machine. That means if those 2 cases are already checked, it should be the inverter itself.

[Nycto]

No red tint to speak of, and playing with the brightness hot-keys does not do anything for me. No changes in brightness when shifting the lid.

The light itself, for whatever reason, is totally out. I have a work light aimed at it, which allows me to make out open windows due to their white backgrounds, but if I remove my work lamp, the display might as well be off.

Hoping it's not the back light because this is a UXGA panel, and I don't really want to open it up to replace it. Not sure how readily those can be bought any more.

[RealBlackStuff]

It is probably a blown fuse near the LCD-connector on the motherboard.
If not, to replace the CCFL if the backlight is gone, see what I wrote 8 years ago: viewtopic.php?f=31&t=88991

[kfzhu1229]

Efficiently replacing the backlight of those UXGA panels without side effects took me like 4 tries to practice.
It wasn't also helping very much that the leads on the replacement bulbs I had are too long and might short out if I don't bend them, and on top of that, my replacement bulbs are made from glass - and that I almost cracked one of those (it was a chip at the end, but so darn close to having mercury spills)
At the end, I am glad that I have performed such tasks on 3 of those A3x UXGA panels, 1 on a T4x 14" SXGA+ panel that I eventually sold as a part of a modded 14.1" SXGA+ A31p, and that I destroyed none of the panels (but cracked 2 cheap XGA panels that I extracted the backlights from)