For a change-over, turn on the motor of the incoming projector at the sight of the cue and almost immediately afterwards turn on the lamp of this projector, at the same time turning off the lamp on the other projector. A short time afterwards, or as long as the cue dictates, fade over the sound. When the film is run out of the outgoing projector, turn off the motor. This difference in procedure is necessitated by the aforementioned points of difference, and are important. If the projectors are set just far enough apart so that each projector switch can be reached at one time by stretching out the arms when standing between them, these operations are quite easily carried out.

280. Location of Troubles. -It is the purpose of the trouble chart to list, in tabulated form, troubles which may possibly occur, and the suggested remedy which in most casts can be effected quickly. The method and procedure are similar to that for other equipments.

The trouble chart is for the purpose of aiding the operator in locating the cause of "no-sound," low volume, poor quality and noisy operation. In case of "no sound," before referring to the chart, check the operating procedure and see that no error was made in setting up, check all cable connections and check to see that the exciter lamp of the "faded in" projector is lighted and that all tubes in the amplifier unit are lighted.

281. Use of Trouble Charts. -When -using the chart look along the left-hand column for the section corresponding to the type of trouble experienced, then look in the "Indication" column and note if any of the items listed there correspond to the nature of the trouble found. The "Cause" column should then be consulted for the probable cause of the trouble, and the "Remedy" column for the suggested remedy.

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