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Circuit Description—Type 422 AC-DC
SW1001
Fig. 3-12. AC-DC Power Selector detailed block diagram.
operated from an AC line. If the internal temperature of
the instrument exceeds a safe operating level, TK1000
opens to interrupt the applied power. When the tempera
ture returns to a safe level, TK1000 automatically closes to
re-apply the power.
AC Rectifier.
The voltage at the secondary o f T1001 is
rectified by the AC Rectifier D1002-D1003-D1004-D1005.
Diodes D1003 and D1004 comprise a center-tapped full-
wave rectifier to provide rectified AC voltage fo r operation
f r o m
a n
A C
l i n e
v o l t a g e
s o u r c e .
D 1 002-D1003-D1004-D1005 are connected across the
secondary o f T1001 as a full-wave bridge rectifier to pro
vide about twice the rectified voltage obtained from
D1003-D1004 (notice that D1003 and D1004 are a part of
both rectifiers). This voltage is connected to the Battery
Charger stage to recharge the internal Battery Pack. Capaci
tors C1002-C1003-C1004 filte r the output voltages o f the
AC Rectifier stage.
Battery Charger.
The rectified voltage produced by the
AC Rectifier stage (full-wave bridge portion) provides a
charging voltage fo r the internal Battery Pack as controlled
by the Power Mode switch SW1030. Transistors Q1023 and
Q1033 are connected as emitter followers between the rec
tified voltage from the AC Rectifier and the Battery Pack.
When the Power switch SW1001 is on and the Power Mode
switch SW1030 is in any position except OPERATE
11.5-35V DC or OPERATE I NT BATT, rectified voltage is
connected across the voltage divider composed o f R1022
and zener diode D1022. The anode o f zener diode D1022 is
connected to the positive terminal o f the Battery Pack
through D1016, SW1030 and F I 014, and therefore main
tains a level at its cathode and the base o f Q1023 about
eight volts more positive than the potential at the positive
terminal o f the Battery Pack. The base level o f Q1023 sets
the base level o f Q1033 to determine the charging current
through R1033, Q1033 and R1034. In the CHARGE BATT
115V AC and CHARGE BATT 230V AC positions o f the
Power Mode switch, the charging current is connected to
the Battery Pack through TK1033, by-passing R1031. A
charge rate o f about 400 milliamperes is provided. Thermal
cutout TK1033 monitors the temperature o f the Battery
Pack during charge time. If the temperature o f the Battery
Pack exceeds a safe level during charge time, TK1033 opens
to interrupt the 400 milliampere charge rate. However
when this occurs, charging current is still applied to the
Battery Pack through R1031. This resistor limits the charge
rate to a 30 milliampere trickle charge. When the Battery
Pack temperature returns to a safe level, TK1033 auto
matically closes to return the charge current to the 400
m illia m p e re rate. In the OPERATE 115V AC and
OPERATE 230V AC positions o f the Power Mode switch,
the current path through TK1033 is open. The charging
current is applied to the Battery Pack through R1031 to
provide a 30 milliampere trickle charge.
3-21
Summary of Contents for 422
Page 4: ...R TV 422 AC OC P o p p Type 422 AC DC ...
Page 64: ...Circuit Description Type 422 AC DC 3 26 Fig 3 15 Idealized DC DC Regulator circuit waveforms ...
Page 68: ...NOTES ...
Page 90: ...Maintenance Type 422 AC DC 4 22 Si Fig 4 14 High Voltage Rectifier Multiplier circuit board ...
Page 92: ...Maintenance Type 422 AC DC 4 24 Fig 4 16 DC Power Converter circuit board ...
Page 93: ...Maintenance Type 422 AC DC E 4 25 Fig 4 17 DC Power Control circuit board ...
Page 94: ...NOTES ...
Page 132: ...NOTES ...
Page 158: ......
Page 180: ...B U D C K D A G A N s N e o o o o u p T Y P E 4 Z 2 A C D C 0 2 foe ...
Page 187: ...T Y P E 4 1 2 A C D C l S W E E P T R I G G E R 3 s M 2 0 0 0 0 U P 1268 SWEEP TRIGGER ...
Page 191: ... H O R I Z O N T A L A M P L I F s N z o o o o u p H O R I Z O N T A L AMPLIFIER ...
Page 192: ... ...
Page 195: ...CRT CIRCUIT 10 3 f 8 OS M hS q u a gs u 0 z 3 U js o 0 1 j C V J C J u l Q ...
Page 198: ...FIG 1 FRONT TYPE 422 AC DC ...
Page 199: ...FIG 2 CHASSIS ...
Page 200: ...4 I TYPE 422 AC DC FIG 2 ...
Page 201: ...FIG 3 AC DC POWER SUPPLY s TYPE 422 AC DC FIG 3 ...
Page 205: ......