Yaesu FT-991 AM Issue Resolution
Glenn/WA3LAB found the fix below on the net to resolve the issue with the Yaesu FT-991 in AM mode. The techs at Yaesu they said they’re aware of it, but Yaesu has not put out a bulletin on it.
Both Glenn & I have followed this procedure and it appears to work. I wouldn’t want it put out there without letting people know that they should proceed with care, and not to change anything else unless they really know what they’re doing. Since there’s not many people running AM anymore most people have no idea there’s a problem.
(Warning: once you put the radio into the service mode you can really screw things up, so do this at your own risk.)