: A common "scare" for new techs is the small spark (arcing) that happens when reconnecting the internal battery. According to official Eaton documentation , this is perfectly normal and won't damage the unit.
Before performing any service, you must adhere to these safety standards: powerware ups 9120 service manual
The devotes Appendix B to the proprietary protocol. You do not need Eaton software to service it; any terminal emulator works. : A common "scare" for new techs is
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