Meanwhile I've changed all capacitors above or equal 10µF on my Mac IIci board - no change, still the same problem. Seems to be that exchanging the capacitors does not solve all problems, eh ?

Still working for the first time, but after shutting down and restart try, it makes only a "clicking noise" while pressing the power button on the keyboard

P.S.: The battery is also dead. Does the battery really influence this ?