TM 5-6675-323-14
a.
Power supply control circuit.
P r o d u c e s supply voltages of +15 V, +8 V, and
+5 V, which are used as control voltages within the power supply assembly itself.
(1) Main ac power is input to PCA A9 via an ac receptacle,
RF1 filter, line
fuses and a set of line voltage selector switches. The main ac power
source is
s w i t c h e d into the primary windings of transformer T1 through the LINE
power switch
and the appropriate settings of the line voltage selector switches S2
and S3. Power
transformer T1 provides the proper voltages to the full-wave rectifier
diodes CR1
and CR2.
(2) The rectified output of CR1 and CR2 is filtered by capacitor C5 and
applied to voltage regulator A9-U1 which provides the regulated +15 V supply.
Capacitors A10-C3 and A10-C4 provide additional filtering and bypass for this
supply.
( 3 ) A second voltage regulator A9-U2 provides the +8 V supply using the
regulated +15 V supply as an input. Capacitors A10-C5 and A10-C6 provide additional
f i l t e r i n g a n d b y p a s s f o r t h i s s u p p l y . T h e +5 V (B) regulator A10-U2 functions in a
s i m i l a r manner by using the regulated +8 V supply as an input. Capacitor A10-C7
provides additional filtering for this supply.
( 4 ) The +5 V, +8 V, and +15 V supply voltages are used only within the power
supply assembly and are not outputted to other portions of the plotter.
b.
Plotter power circuit.
P r o d u c e s the +7 V, +5 V (A), +26 V, -26 V, +12 V,
a n d the -12 V supply voltages which are generated on PCA A9 card and regulated by
c i r c u i t r y o n P C A A 1 0 c a r d . T h e plotter power voltages are generated and regulated
by the following functional circuits:
Ac-to-dc conversion circuit
Square-wave conversion circuit
Voltage output smoothing circuit
Timing sawtooth waveform generation circuit
Voltage
turn-on
regulation
circuit
Turn-on/off sequencing circuit
Power-on
detection
generation
circuit
(1) Ac-to-dc conversion circuit.
Converts the main plotter ac power to dc.
(a) The main ac power source is connected to a full-wave bridge recti-
f i e r CR6-CR9 through the LINE power switch and coil L1. Line voltage selector
switch S4 setting determines the filter circuit configuration.
For 100/120 V ac
operation, line voltage selector switch S4 connects the junction of C6 and C7 to the
junction of CR8 and CR9 which converts this filter network into a voltage doubler
configuration.
3-38
