Ricoh FT7770 Service Manual page 95

B0 B1 B2
H H H
H H L
H L H
H L L
L H H
L H L
L L H
L L L
TH-2 provides the temperature compensation factor. The figure shows the
variation in temperature compensation as the resistance of TH-2 changes.
When the bias switch is turned off, TH-2 is removed from the circuit. At
this time the bias output is determined at 30°C + rest time + image density
selection,
output
(O1)
o
volts
10 volts
70 volts
130 volts
190 volts
250 volts
310 volts
370 volts
TH-2 Resistance
2-39
BP
H
L
B3 B4
H
H
H
L
H L
L L
30
April, '89
(O2)
output
0 volts
220 volts
output (O3)
o
volts
30 volts
60 volts
90 volts