Help Please...HP DV4150US power light blinking

Previous problem:
my laptop won't power up when I connect it to the AC adapter or by battery or both. I then charged my battery on my friend's laptop and then tried it on mine. It worked but I need to hook the AC adapter too. So the charged battery will boot the laptop with the AC adapter hooked to the laptop.

The solution: (I may be wrong for doing this)
I changed my mother board.

New Problem:
The new motherboard won't power on. The power button will keep on blinking. I drained the power by removing the adapter and battery, and holding the power button for 1-2 min. I reseated the memory, the wireless card. I removed the BIOS battery and tried it (thought it might be on standby) but still an issue.

Please help on this issue. Thanks.

 

Normally a flashing power LED indicates sleep mode but your first discription seems to point towards a power problem and on some machines this can be indicated by a flashing power LED but I do not know if HP machines do this.

If you haven't already, download the maintenance manual for your machine.

If you would like to check if it's a power problem caused by one of the machines devices you could maybe try starting with the least invasive items by disconnecting the following (at all times make sure the battery and power adapter are removed before disconnecting devices)

1. Hard drive (maybe use a bootable flash drive)
2. Optical drive
3. Remove any excess RAM modules ie just leave one connected

See if you can switch on, get into the BIOS setup if not then swap memory modules if more than one and try again.

If still no joy you could also try disconnecting

4 Mini Board (WLAN)
5 KeyBoard (maybe use an external keyboard)
6 Bluetooth Module
7 Modem board
8 Cooling Fan

Try power again

If still no joy you could also try disconnecting

9 LCD (maybe use an external monitor)

Try again.

If no luck then there are probably a few connectors left you might as well try unplugging.

Depending how far you go and how you disassemble the notebook you may wish to change the order of device disconnection. If at any time you manage to get the notebook to switch on, try switching off and reconnecting one device and see if you can still power on. This way you should hopefully be able to find out which device is causing the problem.

 

mysterious...

it sounds like something is really messed up, how about the charging unit inside of your laptop. maybe that one is broke. if it is working correctly it should charge the battery, automatically switch between battery and ac power, or let the notebook run ac power alone.

from what you write it sounds like the charging unit may be broke... but i´m not tecchie enough to be qualified for such a statement... just a thought