Pulse Generator - Ricoh FT5540 Service Manual

31 August 1989

15.5 PULSE GENERATOR

The main board CPU controls the timing of all machine operations. The timing is based on
how many pulses the CPU receives from the pulse generator. Pulses are generated by the
rotation of a notched disk within a photointerrupter. As the disk rotates, light from the LED
activates the phototransistor each time a notch appears.
If no pulses are received for a 4.5 second interval while the main motor is on, the CPU
displays code SC 61.
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