Two plates. Only one works.

[cliffyk]

Can you post photos of the bottom sides of both platens?

This has to be an adjustment issue, are you 100% certain that when you aligned the "old" platen you loosened the lock screws enough to allow the platen to swivel and move vertically within the holder?

Do not use the "Z=0" function after mechanically aligning the platen. It should not cause a problem--but stranger things have happened.

Here is my recent post regarding the "Z=0" function and my email exchange with Elegoo support.

Here is the most recent Mars user manual (version 20190722), from the USB drive that came with my newest Mars (received May 7, 2020--a silver one, not that that should matter).

Note that the manual platen alignment process (In the "Unbox and Test" section) makes no mention of the "Z=0" function. I have read some reports (unconfirmed) that the menu option is "grayed out" or gone on the very latest machines. Elegoo support's lukewarm responses to me regarding use of the function lead me to believe it may have been eliminated