Hp Compaq Presario CQ40 AC Adapter Charger

I have both a DV4 and Compaq CQ40. My charger went out on my Compaq CQ40 while i was on vacation. I thought it was the laptop but when i used a relative's charger, it worked so i ordered this charger. I got it home, and it would not work on my Compaq CQ40 (no charging light). I plugged it into my DV4 and it worked fine. I did confirm my "broken" charger is in fact broken (outlet cord from plug to adapter does not work. Isolated it down by switching out parts from both cords). Not sure why it isn't working with my Compaq CQ40 (but the original cq40 plug isnt working either with the new outlet cord) so I am guessing the laptop. Wonder why the other charger did work though. Until i can 100% confirm it is my laptop I'll leave it at 4/5 stars. It is lightweight and it will get rather warm because of that, so make sure its in an area where it can breathe. But appears to be a good little charger for the price. Time will tell if it holds up.