I inherited a Wanhao Duplicator 4. When it was shipped to me, the left Y-Axis support was damaged so I had to replace that. After that, the thing worked flawlessly for about 2 weeks. Then it started having problems. Pinched wire, short circuit, replaced the main board and the "key’ board with SD reader. So, it’s up and working, but just won’t print like it used to. The main problem is that everything on the back side of the bed warps off. Everything on the front side is perfect. I’ve gone and raised the bed temp to upwards of 85c (printing with PLA on glass)… just started making things worse and worse. So, dropped the temps back to 70c and while the problem is less, still, the prints towards the back side of the plate warp and become unusable. I have one of those laser thermometers, which is frankly useless for accuracy and expect to purchase a more reliable version here in the next few days. I print exclusively on glass with no additives, never had a problem before. I’m kind of tapped out with replacing parts for this printer since what I’ve spent on it could have bought a new Creality Ender 3 or eq. So, any suggests? Thermistor? It’s really great when it works, and I don’t want to turn it into a table base. Would eventually like to rebuild it and replace the extruder with a Diamond head and new mother board.