x220 wont power if left shut down and plugged in(edit)

[deckoff]

The is the most weird behavior I've met - the x220 (i5, 4287-59G) sometimes will refuse to boot. Pressing the power button does nothing. I will try with battery in or out, re-set the BIOS, and so on. Then, after half an hour random attempts the PC finally booted and works OK. I even use it to write this post.
This happens for third time in the last 24h - when the PC works for a while it reboots without a problem. If left for some time, I have pray to the god of boot to make it boot. It is that random, really.
I have added 60GB SSD in the PCI express slot.
I dual -boot iwth Ubuntu (the machine is Ubuntu certified, so this should not be a problem)
I left the machine plugged in with battery full every time I had this problem.
Please, share any ideas or advises you might have - should I send it for repair how to prevent this thing from happening.

EDIT: It seems the behavior only happens if I leave the PC shut down and the battery is already charged. And I have to leave the x220 connected for a few hours at least. The laptop will power if left unplugged and battery out for a few minutes.

[EOMtp]

... the x220 (i5, 4287-59G) sometimes will refuse to boot. Pressing the power button does nothing. I will try with battery in or out, re-set the BIOS, and so on. ...

Clarification please:
If you get as far as being able to reset the BIOS, then the power button turned on the machine and the machine has booted already. Do you mean that the operating system will not start loading after the machine has booted ..or.. do you mean that the machine is dead because the power button does nothing?

[deckoff]

I mean - I unscrew some screws, pull out the BIOS back-up battery for 30 secs and try to power on again.
The power button will not power the machine at all ( if I see any text on a screen I am never scared)
I use one of these pads with fan, and the fan is powered by a USB. I am almost 100% that I left this pad plugged into the yellow USB (on the right of the x220). I stopped doing that and I have not encountered this problem anymore.

[deckoff]

It seems the behavior only happens if I leave the PC shut down and the battery is already charged. And I have to leave the x220 connected for a few hours at least. The laptop will power if left unplugged and battery out for a few minutes.

[lorddef]

Sorry to post in such an old thread; but I've got almost exactly the same issue. Did you ever get to the bottom of it?

I've got an x220 that all of a sudden appears to only turn on after it's been plugged in for a while, and only when I've removed the battery.

Once I've finally managed to get it to turn on it will work fine, and I can turn it off and on again no problem. However if I leave it for a while (a few hours) the problem returns.

I've replaced the CMOS battery, and the battery holds charge, charges and works well once the laptop does eventually turn on.

Does anyone have any idea why this might be?

[axur-delmeria]

Maybe some bad capacitors in the power circuits?

[lorddef]

Yes sounds like a decent place to start. Does anyone know where I should look to start with?

I've had a little peak at the motherboard, but it's hard to see - all covered in sticky black film - I presume a cooling thing?

Anyway, some pointers would be appreciated.