Which of the following is the procedure for replacing a damaged UPS power module onsite?

For onsite replacement of a UPS power module, Huawei’s maintenance logic follows a safe “isolate → remove → insert → re-enable” sequence controlled by the moduleready switch. During removal, the ready switch must be rotated to theOFFstate first so the module is logically isolated from operation and will not participate in power conversion. After isolation, the four fixing screws are removed and a short waiting period is required to allow internal energy in capacitors to discharge before the module is pulled out. This matches statement②. During installation, the ready switch must remainOFFbefore insertion to prevent unintended startup or arcing during connector engagement. The module is placed in position, inserted slowly and evenly until fully seated, then secured with the four screws. Only after mechanical fastening and full seating is confirmed should the ready switch be rotated to theONstate to allow the system to recognize and bring the module online. This matches statement④.