Signal distortions & spikes on selected channels - Biacore 8K

Hi everyone,

I’m reaching out to see if anyone has experienced a similar issue with their Biacore 8K system and might have insights or troubleshooting tips.

We’ve been experiencing persistent signal irregularities on channels 1, 3, 6 and 8 since June 2026. Below is a timeline and breakdown of what we’ve observed and tested so far.
June 2026: First observed signal disturbances on channels 1, 3, 6 and 8 during routine runs.
July 2026: An FSE inspected the valve block type 4 suspected of causing the issue, but confirmed the part is functioning fine.
August 2026: During PM, new IFC and opto-interface were installed.
System Checks: The engineer performed a System Check post-service, which passed. We ran a follow-up System Check ourselves and it passed again.
Despite the passed System Checks, routine SPR measurements using well-established, long-validated protocols consistently fail on channels 1, 3, 6 and 8:
1. Biotinylated ligand immobilization: Parallel flow of identical solutions across all channels yields clear signal distortions exclusively on channels 1, 3, 6 and 8. This happens reproducibly across completely different biotinylated ligands.
2. In buffer-only runs from the plate: association/dissociation with clear signal shifts on channels 1, 3, 6 and 8 relative to the normal channels; carryover control step with rapid, extreme signal spikes exceeding the detection limit occur on the same four affected channels.
We suspect an underlying microfluidic or hardware anomaly that the basic System Check script isn't capturing.

Attached you will find example sensorgrams showing the distortions and spikes.

Has anyone seen similar issues? Any suggestions on diagnostic steps or specific fluidic pathways to check would be greatly appreciated.