I made "autopower on" MOD to my camera.
(so it will start everytime charger is powered)
Its not perfect, as I found it later but its close. (and work in my situation)
A and X are normally connected when you push power button.
X is around +1.8 volts and A is the actual power signal to the processor.
(I think processor is in "dead" state so its need some volts to get "ignite")
So, I just connected USB and searched by random any good volts.
I find out B will give me around +1 volt so this is my try.
(I find it later, it was not solid, discuss below)
So all I need to do is connect B and A with wire and my MOD is ready.
It was much harder than it seem cause circuitboard is soo small.
My job: (its not nice, tape is only to keep it in place until case)
But my MOD works.
Connecting B and A means it will kind of push and keep power button down whole time USB is connected. And its ok.
But you cant switch to picture mode example. (if you dont unplug)
My camera will record until battery runs out and then it will safely shut down.
When I tested my camera further, I noticed it did not start always.
After exploration I find out that X is most likely charging power to battery.
It will drop to 0.5 volts when battery is full and 0.5 volt is not enough to start.
So my camera start everytime expect when battery is full. (for me, this is ok cause its always empty)
If you want to do this, you should also think "loading LED" X. It will give (if i remeber correct) +2.8volts. And green led is always on when USB connected.
Of course +5 volts would be easy to connect but how much power you can put to startup signal without breaking it? I dont know specs.
Remember, its possible to break your camera easily with this.