Anyone familiar what the PM looks like for instrument Span-8 and liquid system? Trying to troubleshoot some issues that popped up immediately following a PM. I’m not familiar enough with the actual PM protocol to know what things might need closer inspection.
My issues are high CVs and periodic missed aspirations. Very critical and very sudden that these issues started occurring.
Is there any pattern between the Span-8s? One thing that fooled me for awhile was the tubing being coiled around and causing intermittent asp/disps.
How is your water level, are all tubes within the water with no kinking or residue building up at the openings of each?
I don’t know the specifics off the top of my head either, but have you checked to see if the thumbscrews on the Syringe bank are tight? Those being loose could potentially cause those issues.
Checking for any bubbling or leaking along those entire fluid lines (especially at connection points) is worthwhile to look at as well.
Hope this helps!
Good suggestions all around. The timeline of events suggest something specific and affecting the entire system happened, but you are correct that I need to check the basics first.
The problems I’m seeing are across all channels of the Span-8 and reproducible. The only resolution I’ve applied yet is to EtOH wash the liquid system, which had helped in the past with some similar issues. I did check the tubing and it doesn’t appear to have crazy tight coils - pretty normal.
I haven’t yet checked the syringes/tubing at the pump bank nor have I checked the connection at the mandrels, so that’s my next step on Monday. I’ll also inspect the system liquid inlet closer to check that off the list. Hopefully this is something simple, thought the fact that it’s affected all 8 channels has me worried since everything is isolated from system liquid all the way to mandrel.
Is this across all 8 channels or on individual pipettors? Are these repeatable or intermittent errors? Any recent changes made to your consumable definitions? Do you see any drips on the pipette tips? When priming, do you see any inconsistencies in the streams? Any air in the syringes or in the lines? Just some quick troubleshooting, since I don’t know the specifics.
Thanks for the suggestions. Still not sure how this happened, but I need to recalculate and reapply individual channel offsets. The EtOH flush and new system liquid (degassed over weekend) seems to have resolved CV issues. At this point, the volume delivery was reproducible, but significantly off target.
Quick fix is to extend wash cycle volumes and frequency and to introduce step-specific offsets. The correct, but longer, fix is to re calibrate channel global channel offsets for the three ranges, 1-20, 20-200, and 200+.
Unfortunately I could not track down any singular thing that caused these problems to randomly occur. I wasn’t able to find record of any labware, LC, or even calibration changes - so this really is a ghost issue. Tubing connections were all tight and no bubbles were observed in the liquid system for any channel.
Since all 8 channels were affected, I’m leaning towards something software or hardware related. Similarly, since offsets can be applied to successfully calibrate volume delivery, I’m inclined to say that this was likely a software issue, or perhaps the tubing/mandrels were adjusted. It’s a pain in the butt to have to verify working state and to rerun calibration after every service visit, but at least it’s a dependable solution.