116 C The station operator should nor.'iially perform the following maintenance 

 duties; 



lo Keep the. SOFAR station log completely posted at all timeso 



2„ Rotate the input channel and components In an established 

 duty cycle „ 



3c Replace fuses when necessary,, This requires a knowledge of fuse 

 size and location „ All fuses with the exception of that for the 12Z+A 

 Monitor Amplifier are accessible from the front panel of Rack 1„ The 

 fuse for the 124A amplifier is located at the rear of the amplifier 

 chassis, adjacent to the AC input receptacle „ Note that the original 

 fuse (a Buss Fusestat) has been replaced with the "Little-Fuse" type 



4o Remove the accumulation of wax and paper residue daily from the 

 graphic level recorder paper tape feed drive „ 



5„ Although it may be desirable to delegate the care of the break- 

 circuit chronometer to one responsible individual, each operator 

 should note the condition of the wind of this instrument during his 

 watch o 



6 Measurement of self -noise generated in each channel can be 

 readily made once measuring equipment is set up for this purpose^ 

 This may be established as a daily duty performed by the station 

 operator „ 



117 o As the station operator becomes familiar with the theory and operation 

 of long distance sound ranging equipment, additional duties in the maintenance 

 of the station may be expected of him„ These, however, should not be of 

 such a nature as to conflict with the prime necessity of determining the 

 time of a shot signal arrival with maximum accuracy „ 



PREVENTIVE MAINTENANCE 



118„ Preventive maintenance, involving performance checks on the various 

 components of a SOFAR station unit at specified intervals, will not eliminate 

 the possibility of electronic and mechanical breakdown, but will tend to 

 minimize such occurrence's a 



119 o The following suggested schedule of preventive maintenance and the 

 intervals at which each test should be made are subject to revision as 

 dictated by actual operating experience with SOFAR station equipment; 



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