1) Belt Tension: Don't need to sound like a guitar, but not loose. All three tightened the same. Be sure the belts ride over the pulley's nicely. Timing pulley's on the steppers are centered up with the belt and idler's.
2) Carraige and Platform:
2A) Press-on ball joints firmly and complete first. THEN install washers and screws. If you use the screws the squeeze the ball joints onto the carriage or platform, the ball joints might now seat fully and dimensions and geometry critical to parallel kinematics will be off and cause problems.
2B) During carriage assembly, first check plastic bearing sleeves for strings or burr from machining. Press sleeve firmly onto the R4 bearings. Press each bearing firmly and completely onto the carriages and plastic spring arms. Next be sure the two halves of the carriage fit together with only a small amount of squeeze, then install the three screws to secure the halves. Like the ball joints, using the screws to squeeze and 'seat' the bearings will likely break the plastic.
2C) Install those #4 flat head machine screws square and completely until almost touching the screw holding the ball joint on (and that's the last time you touch the end-stop screws
![Wink ;)](./images/smilies/icon_e_wink.gif)
2D) Bowden tube entry and exit from the wire mesh loom can effect bowden-carriage interference, plug connection, and pulling on the platform assembly. Don't exit too close to the top of the hot end - give some wiggle room.
3) Bed Clamps: !! Don't over-tighten these !! Gentle clamp pressure. Over-tightened bed clamps can bow or flex the glass build surface. Use a metal straight edge to check flatness of the bed at room temperature. The Onyx rev8 bed is 1mm thick and 'floats' under the glass to compensate minor expansion. The 1mm thickness allows the glass to easily flatten any warping happening to the heater. Also pay attention to tape and LED leads and the three dimples in the plastic bed insulator that help keep the bed heater (Onyx rev8) aligned. The blocks supporting everything have two different heights. I recommend the deeper side and the glass will sit flush and nicer with the surface of the printer.
4) Wiring / Electrical: I just built this v3 in the pictures last week. It works great and it probed and printed first time, like all our other production printers. I did tweak the z probe offset a little more to bring in an even surface (tuned out about .003") Looking at my pictures, the guys thought it was funny I looped all of my end stop wires together and didn't cut them short. I wanted to do something that might cause noise issues - YOU should cut them down shorter. I did keep my stepper wires away from end-stop and control wires. The I2C going down the bowden line next to the hot end and part fan doesn't matter because the BED and HOT END are NOT ON during probing. I know, you might be thinking, 'what about the probe wires beside the hot end or part fan pwm wires?' We'll, probing is done while the hot end is room temperature and fans are turned off. So nothing is happening there to mess with I2C wires. If you are trying to auto-probe and heat is on, then you're doing it wrong or you have the wrong firmware installed on your printer.
Lastly, I made a 275mm diameter calibration print. Find it here: http://repables.com/r/800/
*** Please check our github for firmware updates *** Our next update will likely be 2016-NOV-11 Friday.