(diagram 4) for focus correction in the
Y
axis. A
sampling of the
+Y
voltage sig nal is converted to a
current sig nal by 0295, and the -Y voltage sig nal by
0195, before being applied to the Dynamic Focus
circuit.
Y O UTPUT A M PLI F I E R
The
Y
Output Amplifier consists of two identical a nd
non-inverting operational a mplifiers con nected in a
differential configuration. For ease of explanation, only
the
+
side will be discussed.
Transistors 0270-0272 - 0276-0284-0286-0290 make
up the active . components of the
+Y
Output Amplifier.
Tra nsistor 0290 provides bias current for input
tra nsistor 0270. The signal from the
Y
Preamplifier
stage is amplified by 0270 and fed to emitter
followers 0272-0276. The emitter followers drive
output transistors 0286 and 0284. The output
transistors (0286-0284) are connected as a collector
coupled complementary a mplifier to provide a fast
linear output signal while consuming minimum
quiescent power.
The output signal at the col lectors of 0286 and 0284
causes a change in the current through feedback
resistor R288 that, due to the input signal, will just
balance the current through R 1 63. Thus the current in
0270 is held nearly constant. Variabl e capacitor C167
and potentiometer R 1 61 (HF Comp) provide a means
of adjusting the ampl ifier response.
H O R IZO N TAL
(X)
D E F LECT I O N
AMPLI F I E R
�
The Horizontal
(X)
Deflection Amplifier processes the
X
input signals and provides final amplification to drive the
horizontal deflection plates of the crt. A schematic
diagram of �he Horizontal
(X)
Deflection Amplifier is
shown i n diagram 2. A detai led block diagram, showing
each major stage of the Horizontal
(X)
Deflection
Amplifier, is superimposed on the schematic with wide
shaded lines to conveni ently locate the components
mentioned here. The stage names (gi ven as sub
headings in the following discussion) can be found i n
the shaded boxes o n diagram 2.
X P R EAM PLl F I E R
Signals t o be displayed are appli ed to J30
1
(+X
INPUT). The X Preamplifier empl oys a matched pair of
FETs to provide a high input impedance a nd
temperature stabil ity. This stage consists of two
identical and invert i ng feedback ampl ifiers, 0320A
-
0330-0334 and 03208-0430-0434, which operate as
a paraphase ampl ifier. A push-pul l signal is produced
at the collectors of 0334 and 0434. The FET gates
a re diode-clamped on n egative-going overdrive signals
to protect the field-effect transistors from excessive
input voltages. Front-panel screwdriver adjustment
R325 (X GAIN) provides a n adjustable amplification
@
Theory of O pe
r
ati o n
-
608
factor to allow a crt full-screen d eflection ra nge of at
least 0.5 volt to 2.5 volts. This control is normally set
to a nominal 1 volt for 8 divisions of deflection .
H O R IZONTAL POSITI O N I N G A N D Ll M IT E R
H orizontal positioning i s provided b y front-panel control
R347, through the current sources of 0342 -0442. The
push-pull signals from the
X
Preamplifier are applied
to the X Output Amplifier after being offset by this
stage. Diodes CR340 and C R440 prevent overdriving
the
X
Output Amplifier by limiting the X P reamplifie r
signals t o within about 4 volts o f each other.
X F O C U S - C O R R ECTI O N P I CK O F F
Samples o f the
+X
and - X signals a r e coupled from
the
X
Preamplifier to the Dynamic Focus circuit
(diagram 4) for focus correction in the X axis. A
sampling of the
+X
voltage signal is converted to a
current signal by 0495, and the
-X
voltage signal by
0395, before being applied to the Dynamic F ocus
circuit.
X O UTP UT A M P LI F I E R
The
X
Output Amplifier consists o f two identica l and
non-inverting operational amplifiers connected i n a
differential configuration. F or ease of explanation, only
the
+
side wil l be discussed.
Transistors 0470-0472-0476-0484-0486-0490 make
up the active components of the
+X
Output Amplifier.
Transistor 0490 provides bias current for input
transistor 0470. The signal from the X Preamp l i fi er
stage is ampl ified by 0470 and fed to em itter
followers 0472-0476. The emitter fol lowers drive
output transistors 0486 and 0484. The output
transistors (0484-0486) are con nected as a col lector
coupled complementary amplifi er to provide a fast
linear output signal while consumi ng min imum
quiescent power.
The output signal at the collectors of 0486 a n d 0484
causes a change in the current through feedback
resistor R488 that, due to the input signal, w i l l just
balance the current through R363. Thus the current in
0470 is hel d nearly constant. Variable capacitor t367
and potentiometer R361 (HF Comp) provide a means
of adjusti ng the amplifier response.
Z-AX I S AMPLI F I E R
�
The Z-Axis Amplifier circuit provides the dri ve signal
to con trol the crt intensity. A schematic diagram of
the Z-Axis Amplifier is shown on diagram 3 at the
rear of this manual. A detai led block diagram, show i ng
each major stage, is superimposed on the schematic
diagram with wide shaded lin es. The stage n ames
( given as sub-headi ngs in the foll owing discussion)
can be found in the shaded boxes on diagram 3.
4-3