Hello, a friend of mine has a Dell Inspiron 8500. He said he hadn't used the ocmputer for sometime because the PSU was broken and he hadn't bothered to get a replacement.

So i plugged in my PSU into the mains and a litte green diode on the PSU lights up. When i plug it into the laptop, the little diode goe out mmediately. If you unplug from the mains and plug he PSU back in again (laptop disconnected) then the green light comes back on, but if you connect it to the computer, the light goes out. The computer does not power up. i tried this three times and even used a different plug socket with only the one device (the computer PSU), but no joy. I then tried the PSU on a Dell Latitude D630 and there was no problem with the PSU and the computer started up OK. The battery is dead on the Dell latitude, so it won't start without mains power.

My question, what do you think is wrong? And, can it be fixed and if so how. i do replace parts on Dell Latitude series laptops, although I don't do soldering jobs.