- Baseline stepping at random
- Random shift in baseline
- ACQUITY TUV
- ACQUITY PDA
Faulty back-pressure regulator.
FIX or WORKAROUND
- Replace back-pressure regulator (700002676).
- If the instrument is thermal control type, replace back-pressure regulator (700010006).
To test if the back-pressure regulator is working, disconnect the fitting from the outlet of the flow cell while flow is on. The total system pressure should drop about 250psi if it is functional.
Please note, the back-pressure regulator is only required for light-guided analytical flow cells.
If the back pressure regulator fails to solve the problem, the issue may be caused by a A to D converter in either the Front end amp or Personality PCB
A-30PDA, A-30UV, UPAPDA, UPC2PDA, UPPDA, UPPDAARC, UPPDAARCB, UPPDA-E, UPPDA-L, UPPDALTC, UPPDATC, UPPPDA, UPPTUV, UPTUV, UPTUVARC, UPTUVARCB, UPTUV-E, UPTUVTC