TM 11-6625-3053-14
115 or 230 volt AC power is connected to power transformer T1 (Item A through the power switch and fuse circuit (Item B
). Low voltage AC from the power transformer T1 is rectified by diode bridge CR1 (Item () and filtered by filter capacitors
C1 and C2 (Item C ). The unregulated DC voltage (about +40 volts) is connected to pins 10 and 16 of the A1 board
connector. Pin 14 is ground (negative). AR6 (Item D on the A1 board is a 15 volt positive regulator to supply power to
AR1 and AR3. AR5 (Item A E is a 5 volt positive regulator to supply power to AR2. CR 2 (Item K controls the voltage
on pins 7 and 8 of AR4 at 35V DC. AR1 (Item G is a 20 KHz square wave oscillator which supplies the clock signal for
the high voltage inverter power supply. AR2 (Item H is a phase splitter which provides complimentary signals to turn the
inverter transistors on and off. AR3 (Item (3 ) is a timer which prevents the regulator AR4 from coming on before an
approximate 2 min. delay. The AR4 (Item J ) regulator circuit controls series regulator Q1 (Item L and is described in
6-7. -325 VOLT REGULATOR (Figure 6-3).
Square wave signals (Item A from AR2 continuously switch Q1 and Q2 of the A2 assembly on and off. This produces a
high voltage square wave at CR1-4, the high voltage rectifier on the A2A3 board (Item B. The magnitude of this voltage
depends on the DC voltage applied to the primary center tap of T1 (Item C ). This voltage is varied by Q1 through R7
from the +40 volt unregulated supply. Q1 is controlled by the output of regulator AR4 (Item a D. AR4 provides constant
voltage regulation by comparing the DC output of the A2A3 assembly (Item E ) with an internal reference. This voltage
is adjustable by R18. AR4 will also shut off the DC to T1 if an overcurrent condition exists. This is achieved by the
voltage across R17.
The -750 volt regulator is actually a 450 volt regulated power supply connected in series with the -325 volt supply
described in paragraph 6-7. AC for the power supply is derived from T1, the same transformer that supplies the -325 volt
power supply (Item A ). The AC voltage is rectified by the rectified and filter CR1-4, C1 (Item B ). Shunt regulator Q1,
Q2 (Item D draws sufficient current to cause the voltage on
6-2