I am rebuilding a Taz 5. I had to replace a few broken parts and now I am starting to test the electronics. It starts and says its firmware is Marlin 2014Q1. I know I will have to update the firmware.
What should happen when I try to do an Autohome?
When I do an Autohome, the X and Y both start moving. The Y moves back and hits the limit switch and stops. But the X is moving towards the right and my limit switch is on the left side. So it is going in the wrong direction from what I have seen other Taz 5s do. I have to turn it off the printer before the X goes all the way to the left. I guess the Z should home after the X finishes.
Any thoughts on this? Thanks.
There’s only one X limit switch on a Taz 5, so if it’s not heading to the limit switch during homing, my guess would be that the X stepper motor’s harness is backward. From what I can see, they’re simple four-pin harnesses that can easily be flipped and plugged in incorrectly.
Check step #15 here: OHAI: Open Hardware Assembly Instructions
And you are correct, the Z doesn’t home until after XY.
Thanks for replying. I checked the wiring and it was ok.
But I looked through the forum and found this related post. x axis now running in reverse direction
After reading the last post on that thread, I checked my X axis belt and compared it with the installation instructions. Yep, I had re-installed it incorrectly. 
After that, when I did Autohome, the X axis started moving to the left towards the limit switch. And it stopped when it was supposed to, along with the bed on the Y axis. Then the Z started to move down towards its home position.
But when the Z got closer to the bed, something happened. The left side started making some grinding noise and it became out of alignment with the right side. The left side became lower than the right side. I had to turn off the machine. It didn’t get close to the Z limit switch.
I ran some tests with moving the Z up and down. I put a level on there and it stayed level in the middle. I tested the Z limit switch manually during an Autohome operation and it was working fine.
I did have to take the machine completely apart in order to replace broken pieces. Maybe it is something with the couplings for the Z.
Any ideas?
I found the issue. There was a bit of binding between a bolt head on the top back bracket on the control box and a bolt head on the X motor bracket.
I switched the bolt on control box bracket to a bolt with a cap head to give me the needed clearance. I had just installed the power supply on that side of the printer with some brackets and used bolts with a cap head. I didn’t think about the control box bracket bolt in the back.
After I changed the bolt, there was no binding. And I completed the Autohome successfully. 
You can see the clearance I have now in the picture.
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