Laptop keeps disconnecting from power

When I use my advent 7047 laptop(it's a rebadged medion laptop), I usually run it off the mains.
prob I have is after a while(can be after 5 mins or sometimes not until after about 15 mins), the laptop beeps and it switches between battery and mains power, beeping each time it does so. I think it may be something to do with the heat the power supply generates as it gets very hot quickly so does the connection I plug into the laptop(the metal part of the plug).

I know it's not unusual for power supplies to get hot but it gets really annoying when it keeps beeping every second and switching back and forwards.

If I unplug the lead from the laptop and leave it for about 10 mins, the power supply cools down and is ok for a few mins when I plug it back in.

Would my assumption about the heat be correct and if so, what can I do about it. I can't just run it off the battery as it only seems to last about an hour/hour and a half just browsing the net and playing music.

Not something simple like a loose connection in the cable is it? I've had that a few times with laptops, especially if you carry them around a lot and the cable wears away. As for the power being hot, that's just what happens with transformers as they step down the output voltage from the mains.

Like Kimo said, make sure it's not as simple as a loose connection between the power port and the adapter...

Other than that, yes your assumption about the heat disconnecting the power from the supply every now and again is perfectly true. It may well be this. Try locating the power supply somewhere wher eair flow will get to it, i.e not behind a desk/cupboard. Also, try standing the power supply on it;s thinnest end, or even raising it off the floor (tie it up with string?). Some psu's have little fans in, i dont advise this, but you could try and clean the fan/grille out of dust if thats bloking air flow. Final, albeit kind of hax way of doing things would be to buy a usb fan (ebay couple of quid?), hook it into you laptop and point it at the psu. It'll be fairly loud, but will keep the air moving around the power brick.

Good luck.

Sounds like a loose connection, or possibly battery contacts problem. Try taking the battery out and making sure the contacts are clean and the battery does not have a lof of movement that might cause problems. It could be heat related in that a component expands with the heat and a dry solder joint starts to cause problems. These things are never easy to pin down, but making sure all the obvious things are in place is a start.

D