Error 255

I know this is old but did you ever figure this out? Anybody has a service manual for this system?

I am also having this problem. Three out of the four arms will force the error to occur.

The 255 dilutor error is likely due to the syringe pump. The best way to resolve this error is to remove the syringe pump. Clean the motor lead screw and guide rod. Remove all the old grease. After thoroughly cleaning, relubricate with new grease. PerkinElmer uses Lubriplate ES-DS. Excerise the pump motor manually by turning the motor pulley. This is also a good time to check the drive belt to make sure it is still in good condition. Also check the syringe as well - make sure the syringe plunger is clean and free of any dirt. You can use 70% EtOH to clean it - just pop off the bottom cap. The syringes do occasionally need to be replaced. Check to make sure they are not causing any bubbles during pipetting. And it is a good idea to perform the 'Syringe Test' at least annual to ensure they are pipetting accurately. Also, the syringe pump can be difficult to reinstall because you are blindly trying to reconnect the RS-232 connector - but be patient and be gentle. You will get the hang of it eventually!

I am also dealing with the 255 error. Question here is - after removing the syringe and valve, and the four screws on the front from the corners, how does one actually remove the syringe pump? Do you just pull it straight out? I'm assuming after the 4 screws are out, the only connection point is the RS-232 connector? It appears to be a Tecan Cavro 6000 or potentially Tecan Cavro 3000.

And it looks like I answered my own question. I took an Allen wrench and wedged it in the opening and was able to pop it off of the RS-232 connector and now have it out of the system.

Once you have the 4 screws off, and the solvent lines disconnected, you just need to pull it out. I understand being a bit weary of that when it is you first time disassembling. The hard part is putting it back. You have to blindly connect it back to the RS-232 connection in the back. Just be patient.