Response from Jonathan: Richard,
 
The Street Fighter Alpha 3 arcade board uses the Capcom CPS-2 hardware. These boards usually have 2 pieces to them: an A board (located on the bottom and contains the JAMMA harness connection, RCA audio outputs, volume buttons and a test button) and a B board (contains the actual game data and is colored by region: blue for USA, green for Japan, etc.). Here’s some more information from System 16: http://www.system16.com/hardware.php?id=795. If you don’t see anything that looks like this in your cabinet then you’re probably missing the board.
 
Good news is that there shouldn’t be any other boards missing as this is the only board required to run the game. Bad news is that Street Fighter Alpha 3 boards are pretty hard to come by. Check out the usual places such as eBay and different arcade forums (we have some listed on the right side of our site under Communities). You might also try posting in the Wanted sections of these forums as well.
 
The power supply fan should be a easy replacement provided that the power supply is still working. If not, you would probably be better off just replacing the power supply completely.
 
Hope that helps. Thank you for your question and good luck with your repair.