Chromatography Forum

Hello I have a Shodex RI-101 that I am getting a NullGlassHomePosition error. The manual says that you have to send it in for service. What is the fix for this? I have not found someone that says they can fix this. Is this something I can fix? Also does someone know a company that could fix this?

Hi

Normally for RI detectors you need to flush reference cell and sample cell with the same solvent to get diode balance 0.
However there should be manual procedure (at least there is for Agilent RI) where the position of the light beam falling on the diode is adjusted using the zero glass adjustment screw (it is not very complicated procedure)
So you've got 2 options:
- send it to service or call service
- or do it yourself (always risky if you have no idea what you're doing)

Regards

Tomasz Kubowicz

Hi

Normally for RI detectors you need to flush reference cell and sample cell with the same solvent to get diode balance 0.
However there should be manual procedure (at least there is for Agilent RI) where the position of the light beam falling on the diode is adjusted using the zero glass adjustment screw (it is not very complicated procedure)
So you've got 2 options:
- send it to service or call service
- or do it yourself (always risky if you have no idea what you're doing)

Regards

Tomasz Kubowicz

First thanks for the information. We always run a purge to flush the reference cell so it is not that. We have the manual but it does not mention how to adjust the zero glass adjustment screw. I have not been able to find any service docs/manuals. Does anyone with a Shodex RI-101 know the procedure for how to adjust this? Which direction to turn it to? I am assuming you are trying to get the reading to 0.