Author Description

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1917 Excerpt:...see if the pivots are loose. 1f the pivots are loose the armature will frequently stick and fall to release the shutter. 1f when a ring comes in more than one drop falls it may be due to a cross in the lines just outside of the board, or else on the lightning strip to which these lines are connected. This can be readily cleared by inspection. The trouble may be due to the fact that the contacts on the magneto side of some one of the ringing keys are not broken when the key is in a normal position. When it is discovered that a pair of cords do not perform their proper function they should be tested for an open or for a "cut-out." A frequent cause of trouble in the jacks is due to the fact that persons will stick pens or pins in them and break off the points, short-circuiting the springs. The only way to discover this is by thorough inspection of the jacks. To see whether the contacts in the ringing and listening keys break in the proper manner the part of the board containing them should be placed between the light and the eye of the inspector. By looking at the keys against the light and opening and closing them it will be discovered whether the contacts break properly or not. Trouble may frequently be removed from the cord circuit by cleaning the tip and sleeve of the plug with crocus cloth. When a switchboard is new and first placed in service particles of metal are frequently found in the jacks, and the board can be cleaned by using a hand bellows and blowing out all of the jacks thoroughly. The accepted method of cleaning key contacts or mechanically testing for opens is by putting a strip of hard-surfaced paper between contacts when keys are open, closing the keys, and withdrawing it. 1f the key does not make a firm contact the paper will be...