Cisco Switching/Routing :: 7513 PSU In TBD State?

I would like to request assistance from all the gurus here for an issue i have with a Cisco 7513MX PSU. There probably arent many people who are aware of 7500 chassis as they are quite old.Isse: PSU 1 failed in chassis and we tried to replace it. Once replaced, we are getting the following output for it:
 
1#sh env all
Arbiter type 2, backplane type 7513MX (id 2)
Power supply #1 is TBD (id 0), Power supply #2 is 1200W AC (id 1)
 
We have been researching on the internet for answers but unfortunately due to the age of this model, there is very limited information available. We did find information which suggested to have BOTH PSU 1 & 2 with same revision. Right now the chassis is running only on PS2, we dont want to take down the chassis just to confirm the revision number on the PSU and there is no way to see that on the CLI. What we can do is get another pair of same revision PSUs, insert PSU1 first THEN take out PSU2 and then insert the same revision as PS1 in PSU2 slot but the moment we insert PSU1 in we get that TBD state which is not normal status and raises our doubts about putting the same revision PSUs with the method above, there is a chance that after we insert PSU1 in, the moment we take out PSU2, the chassis might not run on PSU1 due to its abnormal state.