Specifications

AL-1551 ELECTRICAL SECTION 12-16
d. Rectifying/smoothing circuit on the secondary side
The high frequency pulse generated by the invertor circuit is dropped by
transformer T1, rectified by diodes D51, D52, and D53, and smoothed by
capacitors C51, C52, C53, and C54.
e. Control circuit
The secondary side outputs (24V series, 5V series) are detected by the
output voltage detecting circuit, and the detected signal is fed-back
through photo coupler PC1 to the control transistor Q2 to change the ON
period of FET Q1 in the primary side invertor circuit, stabilizing the output
voltage.
f. Series regulator circuit
This circuit stabilizes the output and protect against an overcurrent by the
series regulator. The 12V is composed of IC51, the 5V is composed of
IC52, the 3.3V is composed of IC53.
(2) FW signal
The AC input voltage is full-wave rectified by D5 and D6. When the
voltage is divided by resistors R18, R19, and R27 and decreased below
2.5V, the shunt regulator IC7 is turned OFF to turn OFF photo coupler
PC3, and turn ON transistor Q3. LOW level output of FW signal is
provided.
(3) Heater lamp drive circuit
(4) High voltage section
a. Invertor circuit
The 24V output of the main section is inverted by the RCC system and
the high frequency power is supplied to the secondary side of high
voltage transformer T101 and T102. The diode and the capacitor for
rectifying and smoothing are built in the secondary side of high voltage
transformer T101 and T102 to provide DC outputs of high voltage. MC is
turned ON/OFF by MC IN terminal, and TC is turned ON/OFF by TC IN
terminal.
b. Series regulator
The GRID output of DV BIAS is applied from the MC output and dropped
by the series regulator.
DV BIAS is turned ON/OFF by BIAS terminal, and the GRID voltage is
switched by GRID L terminal.
c. Dividing circuit
BD OUT takes out a voltage from T102 and divides it with the resistor
and outputs it.