I have been asked to help fix a dead HP Pavllion DV4000.
The Laptop is completely dead, with the power cord disconnected when you switch on the mains the green LED on the PSU DC connector lights up bright green, but when you connect it to the Laptop the LED fades and goes out, this is the same with or without the battery connected.
With a multimeter the power output from the PSU DC jack reads 31v (which is the output stated on the PSU). However as soon as you plug it into the DC socket on the Laptop the LED goes out and the reading (if your quick) is <5v to 0v. Its as if plugging it into the Laptop is causing the PSU to cut out??
WIth the battery connected and the mains power on pressing the power butting on the Laptop does nothing.
Any ideas on how to identify what's wrong?