I have a CTR ER05 50w machine in my D&T department. We have fitted a brand new 50w tube and now when I pulse the tube the machine shuts down and restarts???

When I turn the power settings down on the Leetro control panel from 100% to 75% it fires fine and doesn't reset but with my tube power tester I am only reading 11w when set to 75%??

Could this be a problem with the tube or the power supply. The original tube was 1000mm and the new one I got was 800mm but that shouldn't matter I wouldn't think.

Thank you