vast posts here on black screens of deathh
the screen is 100% black and never once shows text or that HP logo. 100% dead black, then that is the screen back lamps dead
as most long ago did, go dead , just not yours.
called the CCFL lamps dead.
ok the battery out test1
the other check is the fan is the fan blowing, it must or the CPU overheats fast and (it shuts itself off, like magic (intel inside)
see slide show here for Laptop link packup causes.overheated
http://www.pcdied.com/overheated.html
my guess is it is there, below... as all do every one at 20k hours.
see flash light test. there. on test one, do that.?
see test #1 (battery out, ac pack connected and working)
http://pcdied.com/black-screen.html#Basic-basics-101
if the flash sight trick passes, (see data) ask how to fix that
or read the service manual at HP.
see the list of HP , with CCFL here. dv9000 is it.
http://pcdied.com/monitors.html
if yes, ccfl dead
see here
https://www.ebay.com/sch/i.html?_from=R40&_trksid=p2380057.m570.l1313.TR0.TRC0.H0.Xdv-9000+ccfl.TRS0&_nkw=dv-9000+ccfl&_sacat=0
1% fail this way for inverter bad, 1 in 100.
see same page above for inverters sold the lamps run of it and it makes 500 to 1000vdc to do that,, HV inverter.