Machine powered or not when changing batteries?

Should the machine be powered on or off when batteries?

Its a T32-6 and it has:
1pcs 6v 20Ah
3 NicCd 3,6v 250mAh (one on the control and 2 on the X Z C drive)

On my machines powered on or you lose parameters. That said I would refer to your manual to be sure.

Read post #6

http://www.practicalmachinist.com/vb/mazak/dumb-question-about-battery-replacement-sqt15ms-316835/?highlight=mazak+batteries

Every control has its own quirks about changing batteries. Some controls have two battery plugs so you can plug the new one in and then unplug the old one and away you go. Some require you to change while the control is powered on.

Due to the Nanny State we currently live it, changing batteries with the control powered on is now considered as dangerous as sticking your hand into meat grinder. So, many newer controls have large capacitors that maintain the parameters for 30 minutes or so while you change the batteries.

I will advise readers to read what is posted in the link in post #3.

Many commenters shoot from the hip and tell what they do with no regard for what the OP's system is.

For the OP, Power off, you have to pull a board, most you cannot get the battery off with it in the rack.

You have a mill turn system that I have not worked on (batterys on axis drives).

When you are up and running, keep good notes of what you did to bring it back from brain dead. You will need to do it again in the future.

The gel cell backs up a portion of the operating system. When it doesn't hold up long enough, it will reload from the floppy. You need to keep the correct floppy in the drive, life of the charge is less than a week of power off on systems I have worked on.

Parameters, programs and tool files etc. are backed up with the 3 cell Nicad in the panel below the floppy.

Good luck, looks like you are mostly there.
Bill