K40 Just stopped. Message at the bottom DMSG:'SH'l'SX' to unlock Another message DMSG Reset

K40 Just stopped. Message at the bottom DMSG:‘SH’l’SX’ to unlock
Another message DMSG Reset to Continue
Haven’t been able to locate any info on DMSG in the literature.
If I disconnect the K40’s power and unplug my C3D board I can get the K40 to give me jog control but when I execute RUN the K40 and the k40 locks up and I get one of the error messages. GRBL firmware.

Press stop multiple times until you can proceed

OK I hit abort until the unlock displays. I lock the DMSG. At this point I can jog, send the laser head to 0 and Home but when I try to run the job the head moves 4" then locks. If I go through the above steps and try to run the job the head moves another 4" and stops.

Try generating gcode for a simple shape to discard that. Also use slow speed

Sounds like your PSU is dying and voltage drops when motors or laser needs power.