Linksys PAP2 Overheating Problem

Bought it off ebay (new, unlocked NA version) from China and all was well for about 3 weeks. Then Line-1 stopped working: no dial tone, just some popping sound when I lift the receiver. Line-2 was still OK. However, a few days later Line-2 also dies. When unplugging the device I noticed that it was very hot; so I left it unplugged until it cooled down. The cool device came back to life and all worked for about 20 minutes until it got very hot again. Did this a few times and now the Lines can access the internal AVR menu of the device but the SIP connections don't work anymore--even though the web-config shows that the SIP connections are online.