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Replacing cartridge floor contacts


My Form 2 was having problems with frequent “missing cartridge” errors so I decided it was time to replace the contacts which connect to the cartridge. In order to replace the contacts, you have to pull out the cartridge floor assembly. Before you can do that you need to remove the case (6 screws) and the hinged plexiglass cover (4 screws). Formlabs has (or had) PDF documents somewhere on the site for doing this. Once these are removed you need to unplug the connector for the cartridge floor from the printed circuit board at the bottom of the printer and remove the screw at the base of the Z-tower which secures the 3 ground wires. Once again there is PDF document that describes this, message me I can send you a copy if you need it.
Once all the wiring is free, you need to remove 4 small screws on the back of the printer and here is where you may run into problems. On my printer the 2 outer screws came out OK but 2 inner ones would not turn and I stripped the heads on both trying to remove them. So plan B is this:


After drilling the heads off the 2 offending screws, I was able to pull out the assembly, this is what it looks like (after I cleaned up all the spilt resin). Not much to it, just the contact PCB and the gearmotor which moves the arm which squeezes out the resin. Tomorrow I will tell you about removing and replacing the contacts.


Here is the replacement part for the contacts. It is a surface mount device with 4 solder connections to the PCB.


When I remove the old contacts I use two soldering irons so I can melt the solder connections at both ends of the device at the same. Some other useful things to have are solder wick, flux and a tool for prying the device away from the PCB.



After removing the old contacts, the PCB must be cleaned up to remove lumps of solder from the pads. This is where the flux and solder wick come in handy. Once the pads are smooth and flat I swab them with isopropyl to clean up the residue.


Now the new contacts can be soldered onto the PCB.


Before re-installing the cartridge floor assembly I taped the ends of the wires to another piece of single wire, this makes in easier pull the wires through the bottom of the Z-tower.


I was able to extract one of the damaged screws from the floor assembly. the other is behind the motor so I left it alone. So when I reinstalled the floor I used the 2 original outer screws and one pan head screw with a flat washer and lock washer. I plugged the connector back into the motherboard and reattached the 3 ground wires. At this point I reinstalled the cover and the amber hood (without screwing them down) and powered up the printer and did a quick test to make sure it recognized the cartridge.


So far, so good. I jostled the printer a bit, the connection seems solid, but the real test will come when I try doing a print.