Originally posted by Sav'h Steve
A much later update....
I did replace the 6" fan blades in both top vents of the A/S.
Next is to add one or two slower speeds. Pahaska (John) used 2 - 15 ohm resistors to reduce the voltage down slightly for a slower speed.
My question based on Internet search was to maybe use silicon diodes to reduce the voltage down perhaps more efficiently.
Steve in Sav'h
That was 10 ohm resistors that I used, rather than 15 ohm. They come in packs of two at Radio Shack. Radio Shack only had 10 ohm ceramics if I remember correctly.
Not sure what you would do with diodes. A silicon diode has a small forward drop, but you would have to series a whole string of them to get an appreciable slowing of the fan.