![Tektronix 422 Instruction Manual Download Page 54](http://html1.mh-extra.com/html/tektronix/422/422_instruction-manual_1078891054.webp)
Circuit Description—Type 422 AC-DC
Horizontal deflection
signal to horizontal
deflection plates
Fig. 3-9. Horizontal Amplifier detailed block diagram.
zontal deflection signal is an external signal applied to the
HORIZ IN connector. In addition, this circuit contains the
horizontal magnifier circuit and the horizontal positioning
network. Fig. 3-9 shows a detailed block diagram of the
Horizontal A m plifier circuit. A schematic o f this circuit is
shown on diagram 8 at the back o f this manual.
Feedback A m p lifie r
The input sigr
or the Horizontal A m p lifie r circuit is
selected by the T IM E /D IV switch SW440. In all positions
of the T IM E /D IV switch except EXT HORIZ, the sawtooth
from the Sweep Generator circuit is connected to the base
o f Q513 through C511-R511 and R512. C511 provides
high-frequency compensation to improve sweep linearity at
fast sweep rates. Sweep Cal adjustment R512 is part o f a
current divider which determines the sawtooth current
applied to the base of Q513. R512 is adjusted to provide
calibrated horizontal sweep rates.
Horizontal POSITION control R530A and R530B sets
the quiescent DC outp ut level at the emitter o f Q543 to
determine the horizontal position o f the CRT display. This
control is a dual-range control to provide a combination o f
coarse and fine adjustment in a single control. When the
control is rotated, fine control R530A provides positioning
fo r a range o f about 0.5 division fo r normal sweep or five
divisions fo r magnified operation. Then after the fine range
is exceeded, the coarse control R530B provides rapid posi
tioning o f the trace.
For EXT HORIZ operation, an external signal connected
to the HORIZ IN (TRIG IN) connector is applied to the
base o f Q513 through R501, R355B and R510-R512. The
HORIZ ATTEN control R355B (TRIGGERING LEVEL)
provides about 10:1 variable attenuation fo r the external
horizontal signal. For external horizontal operation, the
Sweep Generator circuit is disabled so there is no sawtooth
input. The T IM E /D IV switch connects a positioning voltage
to the base o f Q513 through R516 and R515 in the EXT
HORIZ position. This voltage positions the external hori
zontal display near the center o f the display area horizon
tally when the horizontal POSITION control is centered.
Transistors Q513, Q524 and Q543 are connected as a
feedback amplifier w ith capacitive feedback from the col
lector o f Q524 and resistive feedback from the emitter o f
Q543. Diode D512 in the base circuit o f Q513 limits the
positive signal change at the base o f Q513 to about +0.6
volt. Diode D513 protects Q513 from reverse-voltage
damage and D524 prevents Q543 from going into satura
tion when overdriven (X10 magnification). For X I magnifi
cation (X10 MAG switch pushed in) the resistive feedback
through the parallel paths o f R537 and R527 sets the gain
o f the stage so the horizontal deflection on the CRT is
calibrated (with correct adjustment o f Sweep Cal R512).
The bias network R535-R536 determines the center-screen
DC level at the emitter o f Q543. Mag Register adjustment
R535 in this network is set so tms center-screen voltage is
the same fo r X I magnification as fo r X I 0 magnification
3-16
0
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: ......