Mars Pro "Set Z Home" seemingly not working

[cliffyk]

I sent an email to Elegoo support asking specifically about the [Z=0] button intent and function--that was at 9:32 a.m. EST; i will report if I hear anything back...

Did you hear anything back?  Just got mine, leveled it according to the one sheet of paper and nothing but buzzing and nothing works.  Screen works on the test, nothing prints.  Seems this firmware is so buggy that I have to go at least 5mm to make it move the paper.  Pretty frustrating as I have had 3 FDM printers and deal with leveling just fine with those.

Nothing yet, and I am not holding my breath, at best I've had 50/50 success in contacting "support" for these sorts of (Cheap Asian) products. Though others have reported good things about Elegoo's support--we'll see.

Are you 100% certain both platen locking screws were loosened and the platen was free to swivel, swing and move vertically against the spring force of the holder?

I have had three of these now and have never had a problem with the platen alignment. When the locking screws are loose the platen should move almost 10 mm vertically with the internal spring wanting to push it down (gently, it is not an especially strong spring).