ATA Analox Analyser, old He cell?

[Agro]

TRIMIX ANALYSER FOR TECHNICAL DIVING - ATA PRO - Analox
I calibrate the analyser on air: zero % He. I measure pure He and get 95% He. I recalibrate, same result.
I know this beaviour from an old O2 cell but does the He cell act the same way? Does this indicate my He cell is old and must be changed? Or is anything else wrong?

I have no idea how old my He cell is.

 

[Miyaru]

How did you calibrate with 100% He? Did you calibrate by turning the potmeters on the pcb?

 

[Agro]

Please read my post. I calibrate with air, zero % He. I measure with 100% He and get 95%

 

[rjack321]

Please read my post. I calibrate with air, zero % He. I measure with 100% He and get 95%

You dont calibrate instruments with zero. You need to calibrate with a known gas close to your target concentration.

 

[Agro]

The manual sais: calibrate He on air.

 

[Miyaru]

Open the analox. You'll find these calibration potentiometers.

Follow these instructions:

 

[Agro]

Great video, thanks a lot Miyaru!
Why the hell does the manuel not tell about this He potentiometers?
It seems that using these potentiometers is not only necessary when changing sensor but also when sensor is a few years old, maybe even earlier.