The acetone+alcool combination seems to have produced some effect, but I'm not sure if this is to be interpreted as a positive progress or a bad sign.

Apparently, the system now *seems* to try a boot: it chirps rhythmically and sometimes lights up the screen accordingly to the rhythm, however still no sign of success.

I'm not really sure if having gone from a no-sign-of-life situation to some chirping madness is actually good, or if things are getting worse...

I uploaded a video to show the defect.