The robinson POH has a safety notice for flying near broadcast towers.
It says that early indications of a high power radio field include strong interference with the intercom system and radio receivers. Then it says that increasing field strength can cause random illumination of warning lights and erratic governor and tachometer operation.
This sounds exactly like what your friend flew into. The POH also warns that many pilots are caught tuning the radios trying to get rid of the interference when the governor goes nuts.
[This message has been edited by baranfin (edited 01 July 2001).]