Elegoo Saturn inconsistent build plate

[Chetty]

Hello, 

I hope this is just a newbie error and an easy fix.

I am new to resin printing and i got the Elegoo Saturn and love it. Recently i have had issues where i noticed the print had a defect during print and so i stopped it mid-way to save resin. After i cleared the plate and cleaned the tank and went to start the file over the build plate (already at the top) tried to raise up and would have gone over had the stopper not been there. I hit stop again and manually moved it down and tried to start again and had the same issue of it trying to go over the top again so i hit stop and manually brought down the build plate to prevent damage. On the third attempt it printed just fine as if nothing was wrong. After the print fully finished and i cleaned everything up i needed to run the print again

This go around the build plate didn't reach the home position and it started to print on the FEP so i had to clear the tank and try again. 2nd try the build plate tried to go over the top, stopped and it started to print on the FEP again so i had to stop. The third time the plate started to try and go over the top and printed to the FEP  4th attempt,, so i didn't want to keep cleaning everything i tried to run the print with an empty tank and if it worked i would pause and fill tank which worked flawlessly for 2 prints after that. 

Now i am trying to print a file and i am cautious it is going to mess up again so i tried the same tactic of starting the print without any resin and if it started to go down first i would add resin and the build plate. issue i had this time is i think since i was trying to add the build plate while in motion it thought i was at the LCD and stopped and started to print to the FEP. So i stopped and cleaned the tank lessons learned. When i tried to start the file over it only came down a little bit and stopped and printed to the FEP again. so i cleaned the tank again. Next attempt it tried to go over the top. Next attempt it tried to go over the top. Last attempt it tried to go over the top and stopped against the stopper and printed to the FEP. 

What am i doing wrong because it was fine until the first time i had to stop mid print and it seems like it has had issues since and they don't seem consistent enough to really figure out what the real issue is.

[billtodd]

I would check the motor to lead-screw coupling (and motor mounting screws) . It might be loose causing the position of the plate to shift

[Chetty]

I would check the motor to lead-screw coupling (and motor mounting screws) . It might be loose causing the position of the plate to shift

Thank you i will check that. since my post i reset the home position and was able to print 3 runs of prints without any issue. tonight i just turned the power on and tried to start a print thinking my issue had been fixed but as soon as i hit print the plate dropped 10mm and it started to cure on the FEP again. when i hit stop it tried to go over the top again. i manually lowered the plate by 50 mm and hit home and it moved up 3mm and that was it. 

am i suppose to be resetting the home position every time i turn off the power using the power switch in the back? I thought the printer was suppose to save settings even in the event of power failure.

[billtodd]

>>>am i suppose to be resetting the home position every time i turn off the power using the power switch in the back? I thought the printer was suppose to save settings even in the event of power failure.

No , it should remember the home position and it should only be necessary to level the plate if it has bee moved (i.e. when removing a particularly stubborn part)

[Chetty]

>>>am i suppose to be resetting the home position every time i turn off the power using the power switch in the back? I thought the printer was suppose to save settings even in the event of power failure.

No , it should remember the home position and it should only be necessary to level the plate if it has bee moved (i.e. when removing a particularly stubborn part)

So i have been very reluctant to 3d print again since this issue first came up (kinda killing the mood when i have to fight it every timee) today i tried the same old fix-it issues i tried before but when i hit home the plate just goes up. when i hit print it stops half way and the UV lights kick on and it is back to printing on the FEP again. I am officially at a loss when it comes to fixing this thing now. any other suggestions on why the build plate is not saving my set=0 or home position and why it only moves up 3mm when i hit home?