There is a way to adjust the s-meter from a menu system. Go to www.members.home.net/k0lee/
Once on his page scroll down until you see the link for "Check out my Ham Radio Page. Click on that link. You will be given a menu that will list a FT100FAQ. Click on that. This will give you a long list of different questions raised about the FT-100. You will find a link for the S-meter. It will show you how to enter a menu system on the radio that yaesu does not put in their manual. However, although there are reports of the s-meters being really stingy, even if you adjust you can not be sure you have calibrated it correctly.