seems to overheat when any (new or old) battery is charging

When the battery charger (magsafe) is plugged in it seems that the laptop gets very hot (smc fan control app indicates this) and then hangs when it reaches about 64 deg. C. This is with a new or old battery.

Also when trying to repair the hard disk when booted in 'target' mode and accessed via firewire, the Disk Utility will eventually report a disk hang as reporting a 'bad key' and then giving up. The unit is also extremely hot at this point.

I am not sure what to do next, except for pull the hard drive itself and see if I can get the volume and disk fixed, and see if not having the disk installed internally will make any difference. I had replaced the hdd about 6 months ago and had no problems until recently. The new hdd is a 320 GB Fujitsu 5400 rpm SATA. I had also replaced both fans about 6 months ago.

I have news: the hard drive was getting very hot, but that was a side effect I bet. Took it out and ran the laptop w/external boot disk, battery is out also.

What gets super hot is on the logic board, right above the HDD mount, between the HDD mount and the fan on the left side right by the side of the enclosure. Is a chrome rectangle about 1.5" x 2" marked with a 'model No. AR58X86" and there is an FCC ID on there too, so I guess this is the airport widget?

It gets too hot to touch except for a split second.

This HDD is the second one , so 2 total have dies untimely deaths so far, I suspect its this super-hot thing that just eventually fries them.

Both cooling fans I have already replaced right when I replaced the HDD last time.

So is this possible, a super-hot airport widget is causing this severe overheating?

Thanks for everything, everyone. ifixit.com is nothing short of a 'godsend' !