Tech Notes
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Title: Troubleshooting the Micro-Bath stir bar
Created: 16 Apr 2012
Last Revised: 16 Apr 2012
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Applies To: All 6102, 7102, and 7103 Micro-Bath Calibrators
Problem Description: The stir bar will not move or moves slowly inside the Micro-Bath. The Micro-Bath is not stabile.
Resolution/Work Around: First, try a Master Reset. This will clear any anomalies with the controller and set the Micro-Bath back to default values.
Second, check the Micro-Bath’s stir speed. Each micro-bath has a different stir speed for different fluids. Check the manual for the appropriate stir speed for your fluid type. The factory defaults are: 6102, stir speed 25, fluid 200.20 silicone oil. 7102, stir speed 20, fluid 200.05 silicone oil. 7103, stir speed 15, fluid 200.05. Pulsing of the stir bar is normal. If the stir bar is stopping too long, the stir speed can be increased slightly depending on the desired vortex. Caution: Setting the stir speed too high will cause the stir bar to disengage.
Third, check the stir bar and tank for wear. The stir bar should have a ring or ridge in the center of the bar. If the bar is worn down or is flat, replace the stir bar. If the tank has a large enough dimple in the bottom to make the ridge on the stir bar useless, replace the tank assembly. On the 7102 the bearing disc can be replaced before replacing the tank.
Fourth, open the unit and remove the stir motor from the bottom of the tank. If the stir motor is spinning, check for dust, debris, cracks in the fan housing, and rub marks on the bottom of the tank. If cracks or rubbing is present, replace the stir motor. If the stir motor is ok, check the voltage at the analog board going to the stir motor. Set the stir speed to 40. The reading should be approximately 12V. If the voltage is 9V or lower , the analog board needs to be replaced.