Laptop won't turn on for half an hour if turned off
I still have not managed to figure out exactly how the computer is behaving but it seems that whenever I turn it on (being it connected to the power supply or the internal battery) it will remain on without any problem until it is turned off.
Afterwards, it will require around 30 minutes completely off (with the battery connected to the motherboard, tho) to turn back on. During this time window, the following symptoms can be observed if the power button is pressed:
- The screen remains black
- No chime
- The fan starts to spin and immediately stops
- The sleeping light is turned on and immediately turned off
- If the power supply is connected, this will keep happening periodically (as if I keep pressing the power button). I still wasn't able to notice if this also happens when connected to battery-only.
I have already tested it with all possible combinations of ram chips in both slots, no hard drive, no peripherals at all, no DVD unit and SMC reset all with no success.
I have tried to turn it on without the battery connected to the motherboard but it doesn't seem to work at all, even after 30 minutes (plus the battery meter LEDs blink 5 times if I press the button to their side, but that's to be expected as there is no battery, right?).
What should I do? Any troubleshooting hints (even if it involves measuring voltages across the board)?