Galaxy CO-48R CO2 incubator problem

[relaxin]

I purchased a New Brunswick Galaxy CO-48R CO2 incubator. It worked fine for a year or two. Then one day the CO2 reading suddenly became 0%, and yet the cell culture media turned yellow. It seems either there is a malfunction of the auto-zero air pump or of the CO2 sensor, the incubator cannot detect the CO2 level. As a result, CO2 continued to enter the incubator. High level of CO2 makes the cell culture media turn yellow, and all cells died.

Anyone has this experience with Galaxy CO-48R CO2 incubator?

[relaxin]

Well, it turned out to be a faulty autozero air pump. When it is replaced, everything works fine again.