02-07-2011 09:15 AM
I will write my problem, which is mostly copy/paste from the above post, for tha sake of usability.
The laptop in question is a client's dv6700 series laptop. In detail, it's this model:
HP Pavilion dv6770ev
With the battery seated, whether or not the laptop is connected to AC power, pressing the power button causes the Battery LED (lightning bolt) to blink 3 times, and then nothing. This must be the drained battery notification. When tested with a battery with some charge left, the laptop powered on and booted into Windows. I get the 3-blink lightning LED effect only when I try to power up the laptop with the battery on, regardless of whether the AC adapter is connected or not.
If the laptop is connected to AC power, the ring around the power connector lights up. This is the only other response the machine shows to any action. I've tried a Hard Reset, as instructed by the HP Authorised technician over our telephone communication (removing AC and battery, then holding the power button for 30 seconds), but unfortunately nothing changed.
I have measured the AC adapter and it outputs 18.89V DC, which is within spec (19V), and also used it to power up my sister's HP Pavilion dv6181ea succesfully, as well as charge her battery. So the AC adapter is not at fault here.
I used the hardware service manual and completely disassembled the laptop. I tried to test whether the USB/Power connector board 90W (HP 446524-001) is the one to blame for the laptop not charging or working at all on AC power.
Upon inspection, I noticed that the board connects to two distinct points on the motherboard. Having used a multimeter and verified that the AC adapter is indeed good, I measured the two cable ends, and while one of them gives 18.9V, the other does not show any voltage whatsoever.
So, my question is, shouldn't both ends of the USB/Power connector board give 18.9V output? Is this a definitive indication that my Power connector board needs replacement, or should I also be worried about the charging circuitry on the motherboard itself? Any way I can do some more testing? I tried to find a datasheet of the 446524-001 and check for the expected voltages, but failed. Any input and help is greatly appreciated.