looking for ideas of what could be wrong , as the laser tube is not firing:

--all power supplies are running , green led's showing green, laser tube
power supply fan is running looks ok
--checked the lid switch which has an led
--I bypassed the cooler cw 5200 outlet filter thinking it was restricting the flow
it did not make any difference
--I cleaned the cooler filters which were clean
--i changed the usb cable to the computer made no difference
-- When the usb is connected to the computer the laser moves very slowly and noisy like its in low gear
--pushed the system reset front power voltage 1 reads 4.89volts
--laser runs smooth with no computer hooked up via usb
--computer will not communicate with the laser says it fails, when i try to download or read settings from the laser
--my controller is RDC6442S-B (EC)
--diagnostics off the small screen does nothing
-everything was running fine until the 48v ower supply failed
machine alarm says machine protected
I cannot seem to think of any other permissive to stop the tube firing
any ideas would be welcome, as I seem to be on my own