Be careful- you might want to tape some little cardboard covers over the high voltage contactor terminals for any live testing.
Then the only voltages you would be exposed to would be 24 volts which is pretty safe.
Better yet, if you have someone else come in to work on it, would be to disconnect the contactor power but keep only the stepdown transformer powered. Then troubleshoot the 24 volt system by itself in total safety- measuring coil voltages and listening for contactor clicks you or someone could puzzle it all out at your leisure with no danger, then re-connect the high voltage as the last step. That's the smart, safe way to do it.
Last thing you need is a lawsuit if someone got hurt or killed.
Good luck- that's a nice machine you've got there
M