Lost communication with control box

[gregg]

I used my bot this morning and everything worked as normal, went to use it this afternoon and it lost communication with control box. PRT 96 running 3.4.27 software. Grounding and cable connections all look good. I get a "missing com return" message. I have tried rebooting, reloading firmware, and changing comm port, nothing seems to help. Suggestions?
Thanks

[dubliner]

The same thing happened to me on Saturday, & it turned out that the USB card went out. It didnt give any notice at all as it had cut a 3D file the night before without error. Perhaps?

[gregg]

I believe I have missed the obvious. Control box power switch lights up when I turn on but I don't have green lights on drivers and power supply fan is not running. I will replace power supply. This happened on my other bot so this really should have occurred to me sooner. Hopefully this takes care of the problem.
Thanks