The RD board should have nothing to do with which flippers operate at all.
You should check the 12VDC power supply.
TZ has a FlipTronics II board in it.
Here's some info...
http://www.pinwiki.com/wiki/index.php?title=Williams_WPC#WPC_FlipTronics_I_.26_II_Boards
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Chris Hibler - CARGPB #31
http://www.Team-EM.com
http://webpages.charter.net/chibler/Pinball/index.tm
http://www.PinWiki.com - The Place to g ofor Pinball Repair Info