Ive got a 2013 Supertec Planotec 2040NC surface grinder. Had it for a few years and never a problem. Went to use it today after it sat a few weeks and got this error below. "Low battery". It displays the Supertec splash screen but no grinding info. Anyone know where the battery is or what type? Shihlin AX2n-32MR-ES PLC. Put an email into Supertec but no response yet. I assume Im screwed, but any help appreciated. I only have the user manual for this machine. No mention of any battery of course.