I have a dell laptop charger that works and a compaq laptop that doesn't turn on anymore because of a dead battery. The end connector seems to be the same on both chords. Can i plug the dell charger into the compaq to check to see if I need to replace the battery or the charger.
If the voltage is the same and the Dell charger is capable of delivering the same or more current than the Compaq charger, you should have no problems using it. I've repurposed many laptop power supplies over the years without issue but I'm always careful about matching voltage and current output.