BELL ADJUSTMENT


ADJUSTMENT OF MAGNETO BELLS          

1. General
Before adjusting any type of bell, the gongs must be twisted clear of the striker and the armature checked to see there is no tightness in the pivots. Ref: E.I. TELES Stns. A3113 & A5905.

 

2. Bells No. 59A

  1. Check that the striker hits the edge of the gongs.

  2. Check that the striker shaft is straight and at right angles to the armature.

  3. Slacken the armature locking screw and adjust the armature to clear the coil face by 20-25 mils. Ref: E.I.TELES Stns. A5253. (The dial on 700 type telephones should first be removed to gain access to the Bell No. 59A-1 to adjust the armature travel slacken the two screws on the centre limb of the bell. The screws should not be removed as difficulty may be found in replacing them).

  4. Set the gongs to just clear the striker when the armature is hand operated.

  5. To increase the volume of the ring, the armature travel may be reduced to a measurement of not less than 15 mils.

  6. To reduce the volume of the ring, the gongs should be set nearer to the striker.

  7. Only Bells No. 59A are suitable for use on circuits using 50 c/s ringing current. Adjustment is as above except for 3.  Adjust the armature to c1ear the coil face by 10 mils without binding.

3. Bells No. 67A

  1. Check that the striker hits the edge of the gong.

  2. Check that the striker shaft is straight and at right angles to the armature.

  3. Adjust the armature to clear the coil face by 20-30 mils.

  4. Set the gongs so that the gap between the striker and the gongs is 10-15 mils when the armature is hand operated.

4. Bells No. 1A

As for Bells No. 59A, but with the exceptions of 2.1.

5. Tools Required

Gauges, Feeler,  No. 1  (Parts No, l0D, 15D, 20D)  Feeler gauges, for use in checking and adjusting armature and striker clearances.
Pliers, Wiring, No. 2 For straightening striker shaft and for general use.
Screwdrivers Inst. No's 2, 3 and  6 For general use.
Spanners,  Box, No. 16   For use on bell No. 67A gong bolts.
Spanners, Flat, No's  2, 3, 4 and 5. For general use.
 
 
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Last revised: September 21, 2010

FM