PowerBook 100 Fires

Yes, you read that right. The 100 is a nice little computer though short lived in the marketplace. But early models had a burning problem. Because of a tall pin on the motherboard the case would melt and a hole would form in it! The fix is simple. Bring it back to Apple (I can't imagine that you haven't if you smelled burning plastic) and they will simply crimp the pin so it doesn't make contact.
Models that don't have the problem are those with serial numbers of SQ211xxx or SS216xxx and higher. If you had a repair done the correction was made. You can tell because the repair person should have put a small  "®" sticker on the serial number so they don't have to spend time doing the repair again.
By the way, this was the only recall Apple has ever had to do. It occurred in 1992.