Long story short, I sent my unit back on a RMA and paid the fee for a refurb unit to be sent out. I got about 2,600 hours of printing out of that one.
Fast forward to today, and the replacement unit is now doing the same thing as the one I sent back 6 or so months ago.
Behavior:
“Cartridge Removed” and “Cartridge Inserted” appears on the screen, print pauses to sense resin level, then resumes. More frequently now the unit reports “Cartridge Missing” and pauses. I pull the tank and re-insert it and it goes back to work. These seem to be increasing in frequency as time passes.
It looks to me that this pops up whenever the Z axis is in motion, making me think it is a power supply issue. Cleaning the contacts and replacing the tank base unit didn’t help the last one, and I don’t think it will help this one.
With yet another RMA on the horizon, with 2 machines in service, I’m close to done with form labs. I’ve been using them for a couple of years now, and it’s been great, but I just can’t afford to eat a $800 RMA every year.
In updating the firmware this weekend I think I may have stumbled across a fix for the issue…
-Plug in the USB to a PC or other 5VDC source.
I think whatever is reading the cartridge switch is on the hairy edge of a valid TTL high, and the motor movement is just enough draw to pull it below the level to signal a missing cartridge.
I’m not sure if plugging in the USB gives a better ground or perhaps an alternate source of 5VDC, but it does seem to have cleared the issue for me over the last 8 hours of printing.