Work slowly and definitely watch the snap tabs recessed in the front or you will crack her open for sure!
Thank guys. I'll crack her open this weekend and measure the fan.
If you get a comparable replacement fan, this should be about a 10-15 minute job...most of which will be the opening and reassembly effort. But its worth taking your time on the mounting clips as to avoid any "mishaps". The HR24-100 model is likely the easiest of all of them to work with.
The fan itself should be plug and play if it's comparable.
All this, of course, assumes a person is working with an owned unit (disclaimer).
Let us know how it turns out.