On Friday, June 12, 2015 at 12:10:53 PM UTC-4, trader_4 wrote:

Just before taking the motor out, I thought it might be
worthwhile to try cleaning the coils on the theory that if
they were dirty enough, it could restrict the airflow, make
the fan work harder. They didn't look bad at all, but I
cleaned them. First attempt at start-up, the fan wouldn't
go at all, then after about 10 secs, if started to spin
slower than ever. So much for that theory.....

I tried again about an hour later, and it fired right up
normal speed. Ran for about 20 mins, then went to the
slow speed again..... At least I got 20 mins of working
on the humidity/temp in the house. I think I'm going to
try it again a few times, see if I can get it to run enough
to make it more comfortable, then take the fan out tomorrow.

Best price I've seen for the fancy ECM fan is $230 and that was only
at one place, not sure they really have it. Others want
$340 - $380. The motor measures to be a frame 48 size,
can get a PSC one of those on Ebay for $50 with a cap included.
The only remaining mystery is if the mounting holes will
work. I'm guessing they will. So, I'm on the path of trying
to replace it with the simple equivalent PSC. I'm going to
open this one up on the chance that there might be some
obvious component, solder joint, etc that could be fixed.