Lenovo X220 does not start up, start button blinking

Hi ifixit Techies

I have several x220 still running and now the third which has the same problem at startup. After pressing the power button, it just blinks in a 2s period and there is only the harddisk running. No screen, no fan, just the blinking. I already tried to fix it with the procedure to take out the battery and press the power button for 15s several times. no positive result.

It is known that X220 with production dates End 2011 have problem because of a faulty electronic component. Mine has prodction date 11/11 ;-( , other with 11/10

I read in a post, that the mother board might have a progressor power source problem. I don’t have electric plans or manual to the motherboard but can solder and measure.

My idea: When I can change the faulty electronic component on the motherboard, then I am able to fix all my X220 with this error. Others could participate from the solution, since this is a general problem for all X220 with this production date and serial R9-HXXXX .

There are new boards availbale in aliexpress, but I don’t want to spend more money than necessary.

https://forums.lenovo.com/t5/ThinkPad-X-...

My machine: Lenovo X220 4291-4CG, 16GB RAM, 2TB Harddisk, WWAN GSM modem