T400 - dead, brief LED flicker, black screen, any ideas?

[g8tzl]

I've just acquired a T400 from a junk sale to add to my Thinkpad "collection".

When I originally connected the power supply, I got the green and yellow LED. I attempted to boot up immediately (battery would have bene flat) but no boot. I removed the battery but when I reconnected the power supply, I got what looked like no LED and no boot.

I tried all the power switch tricks and disconnecting CMOS battery. The power switch trick (10 brief presses then a 30 sec press) did not work. After I disconnected the CMOS battery and waited 1 hour, when I initially connected the power supply I got a brief flash of the green/yellow LED's then nothing.

But I did notice that when you pull out the power supply plug, the green/ yellow LED's do a quick flicker but its very dim and brief (you need to be in darkened room to notice it!)

I guess I will wait overnight and see if that helps to discharge the caps or something. Or maybe its a hardware fault

Any ideas?

Thanks

[Bruce Guttman]

I had a T410 system do the same thing to me. It was the power jack. Some of the wires had broken so it wasn't supplying power to the Planar. Also, sometimes it would arc.

I'd recommend taking off the keyboard, palmrest, and the bezel and take a look inside.

I had another dead one that had been in water and there was white residue on the Planar. I got that one running by removing the Planar and cleaning the junk off with an old toothbrush. Nice project for a rainy Saturday afternoon. Make sure you download the Hardware Maintenance Manual and keep it on another system nearby for reference.

Good luck.

[Hans Gruber]

Find another known working CMOS battery from another machine and put it in your T400. That would confirm or eliminate the CMOS battery being the cause of your problem.

[Khipata]

It must be a power jack as mentioned above... I too had the same problem and just replaces the jack, replacement is easy and the part is cheap.
Hope this helps

[Sudevan]

It might help to check and see if the RAM sticks are seated properly. In older Thinkpads exhibiting similar symptoms, trying to start it with memory sticks removed one at a time can often help. Let's say you have two 512 MB sticks. If it starts with one stick removed, then that stick is likely bad. Also, try the other (working) stick in the first one's socket to make sure that both sockets are working. If this procedure works, then it is probably a simple matter to find a good memory stick for replacement. Bonne chance!

Sudevan