Panasonic UF-890 Service Manual page 244

Fuser Lamp Drive Circuit
The Fuser Lamp is powered by 115 VAC. It is driven by the LVPS and controlled the FCB PC Board.
When the CN32, Pin 9 (nSSR) on the LVPS goes LOW, the Fuser Lamp turns ON. This lights up the
PC301 LED and activates the CR301 photo-triac, and 115 VAC is sent to the Fuser Lamp. The time at
which CR301 is actually activated depends on the 115 VAC sine wave. When the cross-voltage for Pin 6
and Pin 4 of PC301 is other than 0 Volts (sine wave exceeds 0 volts), PC301 inhibits the activation of the
triac and turns ON the Fuser Lamp.
R303
R304
Fuser Lamp Drive Circuit Diagram
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