K8200 / 3DRAG Heatbed Glass Mod

This was the first upgrade made on my K8200.
The heater bed tends to buckle and in that case you cannot achieve a exact print. The reason is the PCB heatbed does not heat up evenly and often it is braced by the mounting screws.
Additionally, the back side is not reliable enough to hold a object.
So i decide to use a glass plate. I decide further to turn around the PCB down side up because the board is a FR4- or FR5- PCB and thus has bad heat transfer rate.

Now, the prints are better