After replacing transformer for Fire-lite MS-2, when plugging in transformer onto main board, power goes off immediately. Any suggestions as to why?
There is a short somewhere on your main board. It may be internal or extremely difficult to find. Replace the main system board and re-try with the new transformer.
Take all of the wiring off of the main board, disconnect the batteries and try powering it up. If it’s ok, add wires one at a time, until the fault returns.