I have been working on a machine with the old Moeller PS4 PLC. I have been testing it for a few weeks. I replaced the battery in it and removed the Eprom to send it to the factory for some tweeks. The machine ran fine for 2 days other than havinng to reset some user parameters every time you turned the power off and back on. Today I powered the machine down and then when I turned it back on the CPU Module has no input or output lights on. The expansion Modules are showing the input and output lights correctly. So my question is did the CPU module go out or is it because the Eprom was removed? I feel like it is because the CPU went bad. Thanks Chris