Cilba:
Sunfish- I have no idea where that notion came from. I flew the F28 (with a couple of breaks) from 1986 until 2007. 17 different aircraft. During that time I never had the APU fail to start, and I found the unit to be totally reliable. We could operate under the MEL with the APU unserviceable, in which case the right hand engine was left running at turnarounds.
By 1986 the APU had been fixed. Ansett went through about 60 broken APU starters by about 1980 and I was asked to find out what was going on. Turned out that the three little fingers of the APU starter clutch sometimes didn't disengage and when the APU fired up the poor little electric starter was over revved until it contacted the casing and failed. Garrett were a horrible company to deal with back then, even Boeing hated them, but they were the only commercial source of APUs at the time. I forget but somebody tried to make a substitute but it never took off.