HP zv5000 shuts down promptly after turnon using a/c or battery power - technical help needed for repair?

I'm attempting to repair a zv5000 for a friend. Unfortunately, shops with technicians are not an option as we've been quoted as high as $800.





Upon powering up using both a/c power %26amp; battery, it turns on for about 5 seconds sometimes getting to logo screen, then shuts down.





On just battery power, power LED turns on %26amp; charge LED blinks.





On just A/C power, LEDs flash dimly %26amp; a quiet clicking is heard near vicinity of cooling fans.





I have checked a/c jack solder joints, power supply, HD, and dirt buildup that could cause overheat.





This problem started about a month after replacing the HP 14.8v 6.0Ahr battery (HSTNN-IB03) with a HP 14.8v 6.6Ahr unit (hstnn00IB04).





No surges occured in A/C house current that we're aware of.





I am aware this is likely to be a mainboard issue, and have confidence in my ability to replace it. My main goal is to find the cause; to prevent its reoccurance.





I've had difficulty finding help, any technical assistance you can provide is greatly appreciated!!

HP zv5000 shuts down promptly after turnon using a/c or battery power - technical help needed for repair?
Because you have already checked if anything was overheating.


I would check if the ram.





If you have two sticks of ram installed try booting with just one. Of course test both of them.