15B & 17B 
Users Manual 
  ii 
Measuring Frequency and Duty Cycle (17B only) .....................................................    10 
Maintenance ..................................................................................................................  10 
General Maintenance ................................................................................................   10 
Testing the Fuses......................................................................................................   11 
Replacing the Batteries and Fuses ...........................................................................   11 
Service and Parts ..........................................................................................................   11 
General Specifications ...................................................................................................   12 
Accuracy Specifications .................................................................................................   14