Ricoh FT7770 Service Manual page 71

Exposure
Switch
Position
Lower
Middle
Upper
- Lamp Safety -
Several safety circuits guard against exposure lamp circuit failure.
SC 1 is caused by the following two status:
1. The lamps light when the main switch is turned on: The CPU determines
this through the monitor signal.
2. One of the exposure lamps opens:
the main board determines that a problem exists.
3. One of the exposure lamps opens:
The monitor signal line goes HIGH and the main board determines that a
problem exists.
CN228-4 Lamp Regulator
CN228-3 CN228-5 Output (RMS)
CN228-6
L
L
H L
H H
2-15
70 volts
75.2 volts
79.75 volts
The monitor signal line goes HIGH and
30
April, '89