elitebook 840 g2 - power button not working

[amelanso]

laptop suddenly would not boot up - unplugged, remove back cover,remove battery, discharged caps (hold power 15s), then when plugging in laptop starts on its own ( no power button press) - boots as soon as plugged in then runs as normal. Power scheme is set to turn off on power button press - but on press  pwr button nothing happens. Scheme also set to sleep on close cover. However after sleep, power button will not wake up or turn on. Have to unplug and replug then machine reboots (as soon as plugged in). Seems like pwr button board is malfunctioning as machine boots when plugging in without pressing button and button will not intiate shut down (or anything else set in power scheme). I have run through the various troubleshooters around power button but I have not seen any post where power button behaves like this and machine boots by itself when plugged in. As it stand the machine cannot sleep since cannot rewake & unplugging clears state. Machine also cannot be on batt as when batt installed, machine will not boot (since power button not working and plugging in also does not cause boot). If machine is on then battery is inserted then machine unplugged, it starts to run off battery.  However must rmv batt to boot by plugging-in which is impractical. Please advise if replace power button board is best course of action... I can make the repair myself but would prefer if some HP tech can chime in. Again I have tried the various troubleshooting SOPs without success and feel this is hardware glitch most likely with power button board...

PLease advise.

Armand

Canada

[amelanso]

update - laptop will only power up if you hold the power button down - if you let go it shuts off (dies). If you keep pressure on the power button it works as normal. Any advice would be appreciated.