Power up a laptop motherboard without power button or power strip.

Yes we can power up a laptop without connecting it's power button board or power strip..!! same as a desktop mother board.
It's safe as well as desktop motherboard just you need to know how power system of motherboard is functioning or how it's work as we press power button.

Switching the power 'on & off' is done by circuits on the motherboard.The circuits are triggered to change state by a momentary shot circuit of two points in the circuit. That is done by the push power button. A short-term connection of that button is enough to turn on motherboard. Usually one pin of on/off switch is shant with (ground) GUN. and second pin of on off switch connected with the circuit and always there is stay a (very low power +voltage) high pulse on the track of the power switch as we press the on off switch switch shot the high plus with Ground. and due to ground, plus trun down to low '0' and circuit turn on the motherboard.
Power on and off system controlled by super I/O chip on motherboard of laptop or some time some motherboard manufacture use some component (IC,Mosfet, Transistor) interface between power button and in I/O (input output controller) chip and mostly power switch being connected direct with I/O.

Is it a safe and easy method to on and off motherboard without connecting POWER button PCB or strip while repairing? :-

It is a good and easy way. If you repairing a major fault of laptop motherboard and while repairing there is need to power up motherboard many time and i think you already know what can be happen if we connect and disconnect a ribbon flex cable many times from connectors, connecting tips of the ribbon flex cable may be get tempted and brake! and it is very hard job to recondition a tempted or broken ribbon cable, even it's also a hard and time consuming job if you looking for a same new one cable in your local market.

So that is a very most common problem with flex cables.

How to find a ON and Off button logic track (PS ON signal) on laptop motherboard :-

It,s very easy to find out form where we can turn on a laptop without connecting it,s on/off switch PCB.

set the multimeter on continuity or buzzer range And simply trace the power switch non ground track from switch to it's ribbon flex cable or connector.

follow this video....

CHECK IN THIS VIDEO DEMO HOW TO POWER UP A ACER ASPIRE 5920 LAPTOP WITHOUT USING THE POWER button board or POWER STRIP :-

And in some of laptop main board you will found a already not connected tips for power on off function, So I putt here a image of this kind of laptop motherboard it's image:-

ON board power on,off tip of:- Compaq Presario V6000,Compaq F700,HP Pavilion DV6000 series,HP Pavilion DV9000 Motherboard,hp pavilion dv7.

But mostly we have to find the PS ON track on main board with the help of continuity meter. :P

HAVE A GOOD LUCK :)