Right steps to replace 4500 ERS in the powered on stack? Help please

[Apollo77]

We have five Avaya ERS 4524 switches in the Redundant cascade stack configuration with MLTs configured on it. After powering off/on the stack the one switch member of the stack (not the base one) wasn't working. The stack reported that he is missing. We have the same switch for reserve and we want to replace the failed one. My questions are:
- Do I have to initially configure the switch to join the stack (IP address for in-band stack, standalone, gw,…) or to leave factory default configuration
- Can I connect new switch to stack while the stack is powered on (I read that this is possible on 5500 series with fast stacking feature, but what about 4500 series). Is the Auto Unit Replacement enabled by default?
- I am planning to upload the same FW and SW to the new switch as the stack versions and then with non-base button connect to the stack. Do I need to disable AAUR or not in this case?
- I have MLTs configured on the stack. Will the new switch “pick up” configuration and be like the failed one. Will the new switch be logically placed on the same spot as the failed one (because of the MLTs issue)?
Any suggestions for right steps would be helpful.
Best Regards

 

[biv343]

If you have auto unit replacement/auto replacement upgrade enabled, simply remove the failed unit from the stack, put in the new switch, connect the cascade cablesm power up the unit and wait about. 10-15 minutes. If you have an uplink/mlt connection in the failed unit, i'd unplug that connection until the unit is in full operation.

That's the beauty of AUR. Connect the new unit, wait and you're done. The worst part is disconnecting and reconnecting the patch cords.