Ricoh FW780 Service Manual - Page 47
FL Regulator Control, D] Main Board
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3.3 FL REGULATOR CONTROL [B] [A] Rev. 5/95 [D] Main Board [C] Light Sensor The FL regulator [A] receives 24 volts dc at CN401-1 from the PSU [B]. The control signal, which is a pulse width modulated (PWM) signal, is received at CN1-3. The PWM signal has a period (T) of 1 millisecond and a duty ratio of 15% to 100%. The basic light intensity level is determined by the image density selected at the operation panel (manual ID control). The CPU uses the light sensor to monitor the actual light intensity. The light sensor [C] directly detects the lamp's light output and feeds a light intensity signal back to CN104-B1 of the main board [D]. This feedback allows the CPU to compensate for variations in light intensity due to the lamp's age or temperature. A163 2-11 SM
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