Symptom Possible Cause Action Ref
Check power supply
Manually turn the stir paddle to
help start the motor
3.1.2
Motor not working on the
5905
Replace motor 8
Check if stir paddle is pushed all
the way in
3.1.2
Replace motor 8
Loud motor on the 5905
Bent stir paddle Replace stir paddle 8
Membrane cap is tight on the
5905
Use pliers to loosen the cap (turn
counter clockwise while facing
sensor tip)
3.2
YSI Incorporated YSI 58 DO Meter 22