I am a DNA forensic scientist and I am currently working on DNA extraction with the PrepFiler kit using a Tecan EVO150. We have been using these for years and have optimized our scripts pretty well.
However recently we have a problem with one of the Tecans, where it has trouble ejecting tip 1 only at one specific spot of the script. It can eject just 1 tip fine everywhere else in the script. I have tried using other channels instead of tip 1 for that specific spot of the script and that’ works too (which could be a solution to this but i still want to figure this out, since we want consistency across all scripts on all of our Tecan’s).
Things we already tried but failed:
import a working script from another Tecan
deleting that line of script and writing it again
Having a Tecan engineer some out and the entire arm was changed
Add in another line of “drop tip” in the script
pray to the automation god
Has anyone had this weird problem before or have suggestions? thank you!!
Hi there,
I have lots of questions for you. Assuming you’re talking about a LiHA:
What kind of tip eject are you using? Lower DiTi eject? The regular tip eject?
Since you mentioned it can eject everywhere else in the script does that mean you are ejecting tips not in the tip waste and in a specific location? If so that points to a location issue and not the something with the actual ejection mechanism (since I don’t know what type you are using.) Tecan should not have released the instrument back to you had it failed one of the tip ejection tests in S&S.
Once you answer those questions I can hopefully help out more.
Yes sorry I should’ve been more clear. I am talking about the LiHA, was trying to eject a 1000uL filtered tip.
This happens during the lower Diti eject (i believe) into the waste chute.
Basically this happens in the beginning of the script when we are checking the deck to make sure we have reagents in the reagent trough. So typically the Diti goes and grab four 1000 uL tip (channel 1-4), then tip 1 goes and liquid detect one of the troughs to make sure liquid is there, then it should go to the waste chute and eject tip 1, then tip 2 goes to another trough to detect liquid, and eject tip 2, etc.
However, right now when tip 1 goes to the tip waste chute location, the ejector doesn’t even engage. Channel 1 goes down, ejector doesnt engage, and then channel one goes back up and moves on to channel 2. Channel 2,3,4 ejects fine. There’s even a line in the script at the end of this to eject all tips, but it still won’t engage.
Super odd, as we have this exact same script on 3 other Tecan’s and they work fine without any problems, and the software version should also be the same.
What’s even more weird is that channel 1 has no problem ejecting either just by itself or along with other channels in any other part of the script!
Does the LiHa have a bracket that hangs down by the channels? If so thats the Lower DiTi eject.
Based on what you described, it sounds like like the solenoid that fires the LDE needs to be adjusted or the bracket itself is bent and needs to be adjusted
we suspect its two fold, likely a weird rare case software bug and mechanical issue. In our case LiHa arm will move to waste chute and try to eject the tip, during the eject, the “swing arm” never engages.
Currently we just left with 2 tip pick up.
