Thinkpads Forum

I have a T440p running Linux (MX26.3), and for quite a while I've had a situation where, when I close the lid to suspend, often when I open it again the screen will remain black, the LED on the power button will just flash 3 times then the computer will be off (no messages, just a black screen and power off.) If I push the power button after that, it will boot normally. Sometimes it will suspend and awaken properly, sometimes I will get the 3 flashes and black screen/power off right after I close it (and when I reopen the lid, the computer is off and must be rebooted.)

But I've had a few times that the 3-flash and crash would happen as I put my hand on the lid to close it.. even before the lid was moved down far enough for the magnetic lid sensor switch to activate. Although I can't find it now, it seems that I have seen references to the cable that runs from the board to the lid/screen sometimes being defective or damaged and causing sporadic issues.

I don't think it is a software issue because of the variations in how it happens, especially without even closing the lid, and it happened with another version of Linux as well.

Does anyone know what the 3 flashes mean?

The LCD cable could be worn and possibly short against some chassis part, causing the crash.
Alternatively, maybe you are "static" from wearing nylon/acrylic/polyester clothing?
Or the charger cable/plug might be worn?

I had not thought about the possibility of a static discharge.. although it is possible, as many times as this has happened over the past year or two, and the various ways it manifests, I think it unlikely. An interesting thought nevertheless.
In looking at Google and other resources, it would seem that the 3 blinks may be pointing to a hardware issue. I have used the diagnostics available by hitting F10 at boot, and the memory, CPU and other hardware checks included in that all came out well, but of course, there is other hardware that isn't tested in that. Like the LCD cable.
That is looking more and more like the culprit. I don't look forward to the disassembly that will be required to deal with it (if I can even get the cable..), but I can lay this T440p aside for a winter project. I still have my Thinkpad R500 that I can use, and having just upgraded the memory to 8GB and replaced the HDD with an SSD, it will do nicely.
Thanks very much for the input. It was helpful.

This might help: https://support.lenovo.com/us/en/solutions/HT510665
Lenovo videos about dis/assembly T440p.

Absolutely! Thanks!

Updating.. we had a snowy day here today and it seemed like a good time to swap out the LCD cable on my T440p.
I managed to get that done in about an hour, without losing any of the screws I think I even got them all back into the right places.
Replacing the cable seems to have resolved the problem. I have closed the lid numerous times since replacing the cable, and each time it suspended correctly and re-awakened without the flashing power button or black screen crash.
Thanks again for all the help and the encouragement.