Oki B4100 User Manual
Page 433
40055101TH Rev.4
433 /
(4)
5V output circuit
The 5V output is supplied by rectification and smoothing of the output of transformer T1 by
means of diode D8, capacitor C16, choke coil L3 and capacitor C17. Variable resistor VR1 is used
for adjusting the output voltage level.
(5)
–8V and 24V output regulator circuits
The -8V output is stabilized by regulator IC2 after rectification and smoothing of transformer T1
output by diode D10 and capacitor C19.
The 24V output is stabilized by Q4, ZD3 and ZD6 after rectification and smoothing of transformer
T1 output by diode D9 and capacitor C22.
(6)
Standby power supply circuit (series power supply system)
Since this power supply is provided for saving of power consumption in the standby state, it is
active until the MPON signal rises to the high level. The AC output dropped by low-frequency
transformer T2 is rectified and smoothed by D11 to D14 and C26, which is then stabilized by
regulator IC3 to supply 5 V(S).
When the MPON is set to high, TRC2 is turned ON to activate the switching circuit.
(7)
Heater control circuit
The ACON control signal on the secondary side is transmitted to the primary side via PC3 to turn
triac TRC1 ON for AC voltage supply to the heater.