Maintenance and Trouble Shooting 



1. To test the instrument for proper function of the circuitry, unplug the electrode. Switch to 

 "Adjust" position. There should be an upscale reading, adjustable with R-9. Switch to 

 "T-Read" position. The meter should read below zero microamperes. No reading should 

 result with switch on "O2 Read" or "Polarize" positions. 



2 . With the electrode connected and the switch on "Adjust" position, the meter reading should be 

 upscale and adjustable. On the "T. Read" position the meter reading should vary as the 

 temperature of the thermistor. On "O2 Read" an upscale reading will be present if the O2 

 electrode is prepared with electrolyte and membrane. If uncovered and dry, no reading will 

 be on the meter. If the platinum and silver are bridged by water or the tongue, an upscale 

 reading will occur . 



3. Batteries are long-lasting. Batteries 2 and 3 should be replaced if the meter will not adjust 

 to the red line. Batteries 1 and 2 should be replaced if excessive time (4-5 minutes) is 

 required for polarization . 



4. Store electrode in water when not in use. 



5. Turn switch to "0^ Read" position and allow 30 minutes to equilibrate when the instrument has 

 been turned to "Off" position. Leave on all day when instrument is being used periodically. 



MICROAMPERES 



Appendix figure: — Example of oxygen calibration graph. Point A 

 determined in water of known O2 content. Point B in water 

 with O2 removed with excess sodium sxilfite. 



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