I am slightly surprised to find you think this controller's components to be expensive. have you priced the parts from Flight Systems Industrial Products? their web site is fsip.biz (not.com)
and sure, there are a number of other controllers that can do the same job. (but I doubt they are less expensive).
If your tech is not all that sure of how to troubleshoot the controller down to the SCR level, Flight systems can do a complete controller repair and get it back to you within a week, but they may well have a unit on the shelf that you can order and have a core charge and credit for, and the cost really should be less than any alternative.