DAD Self Test failed due to failed Spectral Flatness

The spectral flatness test determines the maximum noise (in mAU) on the spectrum. On G1315X/G7115A the test is run with the flow cell removed to eliminate effects due to absorbing solvent or a dirty flow cell. On G4212X/G7117X a test cell should be used. First, a detector balance is done. Next, a spectrum is taken. Theoretically, the spectrum should be flat, however, in practice, noise is superimposed on the spectrum. The amplitude of the noise is a measure of the optical and electronic performance.

Before replacing hardware, I would try running the test again one or two times, but with longer equilibration time.

The spectral flatness test determines the maximum noise (in mAU) on the spectrum. On G1315X/G7115A the test is run with the flow cell removed to eliminate effects due to absorbing solvent or a dirty flow cell. On G4212X/G7117X a test cell should be used. First, a detector balance is done. Next, a spectrum is taken. Theoretically, the spectrum should be flat, however, in practice, noise is superimposed on the spectrum. The amplitude of the noise is a measure of the optical and electronic performance.

Before replacing hardware, I would try running the test again one or two times, but with longer equilibration time.

Update: I just ran the Self Test on my G4212A detector, using a test cell. Spectral Flatness passed with super-low results. If yours are, after re-running the test with longer equlibration time, still that high, I would suspect something with the lamp, the main board or the optical unit.