I recently bought a new H500 online and it has a ton of problems. Firs of all the printing surface is extremely uneven. I am trying to print a large part on a uneven surface and with a raft it would look ok, but I am getting a strange pattern all the way on the surface. It seems that very 50 lines or so it prints a couple of lines higher which do not stick to a part at all. Attached photos of a strange pattern. Would appreciate any help on solving this issue.

Ps. If anyone knows how to fix a current printing surface would appreciate that too.

Hey, Did you figure out what it was?
I bought one H500 also. Staiting to think it was a bad idea…

Just replace glass with new one (strained glass only!).
Original glass from box is curved.
In this video 3D принтер He3d H500 aliexpress (часть 2) - YouTube videoblogger says, that his glass caved in on center for 2-3 mm, and hi bought another strained glass custom one. And that hi wrote to dealer for new 3M scotch for heater and new black sticker.
I bought h500 and my glass curved too, and i’m going to byu new flat.

Just replace glass with new one (strained glass only!).
Look to me answer upper.