Dartron D12 User manual

`~J
INSTRUMENTS
D12
17MHz
DUAL
TRACE
OSCILLOSCOPE
INSTRUCTION
MANUAL
DARTRON INSTRUMENTS LIMITED
Cranes Farm
Road
Basildon
Essex
Tel
02B8
2e1302
Telex BB4B~I
PRECISION OSCILLOSCDPESandELECTRONIC
INSTRUMENTS

The
DARTRON
dual
trace osci
I loscope
D12
with its bandwidth
from
DC -17
MHz
at
10mV/cm
to
50V/cm,
an
2Hz-10
MHz
at
1mV/cm is
a
professional
instru-
ment
suitable
for
use in
the laboratory,
television
servicing
and the
field
of
higher education .
To
ensure
maximum
brightness
of
the d i
sp I
ay
we have
departed
from the more
conventional
monó-accelerator cathode
ray tube
and
ut
i I i se i
n
stead
a h i
gh
performance
5"
post
-def I
ect
i on -accelerator
(P DA )
cathode
ray tube
operated
at 3.5kV
overall. Even
so,
where
additional
bright -
n
ess i s
required at
the highest
writing
speeds i t i s possible to operate
as
a
single
beam
oscilloscope, thus
effectively
dotbling the
brightness.
Dual
trace operation
i
s achieved by
means
of beam switching .
The I
sewer
speeds
from
1.5 sec/cm to
2
m i
1 I i
serf cm
are
switched i n
chopped mode at
200kH
z
approximately.
At
sweep
speeds
between I m i I 1
i sec/cm to
100
rianosec/cm
the
beam
is switched
in
the
alternate
sweep mode. The
mode of
operation
i s
automat
i ca I I y
selected by the
time base
switch and i s
always
appropriate to
the sweep speed.
The
instrument
may
be
operated as
an
X -Y
osci I
loscope, both channels being
independently
calibrated over the range 10mV/cm
to
50V/cm.
The
bandwidth.
of
the
X
axis is
DC-1MHz,
and
the
Y
axis is DC-17MHz. Other
facilities are
available and
are
described
in
this manual .
Stabi I ised supplies
including
both EHT
I
ides
ensures
consistency
of cal
ibrat-
i
on for mains
variation up to -
10%.
GUARANTEE
&SERVICE
The
instrument
is guaranteed
for a
period of two years
from
date
of
purchase.
An
adequate after
sales
service
is
available
to all users and
our
Service Depart-
ment
will
always
be pleased
advise
either
by telephone
or
in writing.
Please
quote
serial
number and date of
purchase
on
all correspondence.
Should
it
be
necessary to
return the
instrument
for
servicing
please ensure that
it
is
carefully packed
in it's
original
carton
to ensure
safe transit.
We
cannot
accept
responsibi I ity
for
instruments
arriving
damaged.
1

Page 3
CONTENTS
Specification
" 5
Operation
" 8
Description
of circuit
"
13 Maintenance
" 17
Parts
List
ILLUSTRATIONS
MQ161 — Y
amplifier,
60 mV calibrator,
beam
switching
circuit.
MD
164 —Vertical
output circuit.
MD163 =trigger
circuit, time
-base
circuit, stabilised±
20V
lines,
stabilised
±
EHT
lines.
Fig.
1
—CRT
circuit,
power supplies
interconnection diagram.
Fig. 2 —
MD161
component
layout,
MD
M
D
164 component
layout.
Fig.
3 —
MD163
component
layout.
2

SPECIFICATION
VERTICAL
DEFLECTION
Dual trace
operation
is
achieved
by beam
switching
in
the
chopped
or alternate sweep
mode.
For
sweep
speeds from 0.5sec/cm
to
2
míllisec/cm operation is in
the
chopped
mode,
and
in
the
alternate sweep mode from
1
millisec/cm
to 1
microsec/cm. The
chop
frequency is
approximately
200kHz and the
appropriate
mode
is
selected
automatically by the
TIME/CM
switch..
Single
beam
operation is
through
the
Y2
channel,
and
is
useful
for
obtaining
maximum
brightness at
fast sweep
speeds when the trace
is
expanded X10.
Bandwidth
(-3dB)
Sensitivity
Bandwidth
Sensitivity
Accuracy
Input
Z
Input
coupling
Protection
DC-17MHz
and
2Hz-17
MHz Y1 ,
Y2
and
single
beam
10mV/cm
to
50V/cm in
1
,2,
5
sequence
2Hz-10MHz -
Y
1
in
cascade
with
Y2
1
mV/cm
to
5V/cm
in 1
,2,
5
sequence
± 3%
for
all
conditions
1
rr~egoFlm
shunted by
approximately 30 pF
DC -
GND -
AC
via
50
ohm BNC
connector
400V
do
or
peak
ac
Horizontal
deflection via
Y1
channel
Bandwidth
(-3dB)
DC-1MHz and
2Hz-1MHz
horizontal
Sensitivity
10mV/cm
to 50
mV/cm
in
1 ,2,5
sequence
horiz
ontal
Accuracy
±
3%
A
I I
other
conditions as
for vert i ca
I def
I ect
i
on
TIME
BASE
The
time
base
may be
triggered
+ve or -ve
internally,
externally
and
externally via
Y1
pre
-amplifier
output
X10
applied
to
the
external trigger socket.
This latter
facility
is
useful
when
the
external
triggering
signal
is as low
as
100mV or as
high
as
400V.
Triggering
may be
manual
only, with
no
trace
in the
absence
of a triggering
signal,
or with
a bright line
display
at
all sweep
speeds
in
the
absence of a
triggering
signal. A
switch
provides
this
option.
Ca I i
brat i on
1
m
í
crosecon d/cm
to
0.5
sec/cm í n
1,
2,
5
sequen
ce
Accuracy
±
3%
Expansion
X10 expansion
switch
increases time
base
speed
to
100
nanoseconds/cm.
Accuracy ±
5%
Velocity
Continuously
variableove~r
range
of
3 :
1.
Reduces
lowest time base
speed
to 1.5
sec/cm
TRIGGER
MODES
Internal
source
Internal
TVF
External
sources
Coupling
Level
range
Sensitivity
2mm approximately
8Hz
to
SMHz
5mm " up to 17MHz
and
higher
In
the
Y1 in cascade
with
Y2
mode
the
sensitivity i
s
i rriproved
by a
factor
of 10 .
Sensitivity
2cm
peak to
peak
video
Sensitivity
1
V
peak to
peak
8Hz
to
17MHz
100m
V
to
400
V
peak
to
peak in
1
,
2 ,
5
sequence
with
signal applied via Y1
pre
-amplifier
X10
AC -AC
fast-TVF
Internal
greater than
8cm. External
greater than
20
volts
3

AVAILABLE
OUTPUTS
Y1 X10
Signals
between
2Hz
and
12mHz
applied to
the Y1 channel are
available at
the BNC output connector amplified
X10. Output
impedance 50
ohms
approximately. Maximum output 5V
Calibrator
60mV
peak to
peak square wave
at line
frequency
Accuracy ± 2%
Ramp
Approximately
10V
positive going at sweep frequency
Gate
+17V approximately from
time base bistable. May
be
used for
probe
adjustment
Z MODULATION
AC
coupled socket
available on r'
ear
panel. 10V produces
visible
modulation
DISPLAY
A
5"
flat
faced post
deflection
accelerator
cathode ray
tube
operated at 3.5kV overall.
DC
coupled
unblanking
completely
suppresses
flyback re -trace
at
all
sweep
speeds, and DC coupled
chop
transition blanking eliminates
background at highest
brightness
down to lowest sweep
speeds
SUPPLY
95-111 V,
103-121 V, 111-130V
190-222V,
206-242V, 222-260V
Consumption 30
watts
approximately
DIMENSIONS
16.5cm (6'h") x
31cm
(12") x
40cm
(15'/z')
45-440Hz
We
reserve the right to
amend
the
above
specification
without
notice.
Any
change
made
will normally
be~
improvement resulting
from
continued development.

OPERATION
SWITCHING
ON
Check
that
the
supply transformer
is
correctly
connected to suit
the
power supply voltage
(see MAINTENANCE
section).
It
is
important
to fit the
correct
fuse —
600
m/A
for
95-130V
and
300
m/A
for
190-26-V
operation.
The
instrument
is
convection
cooled
and
should
be operated
in
a
position
where
external
air circulation is
not
restricted.
The
power
on/off switch is fitted
to the
BR I LL control.
OBTAINING
A
TRACE
(a) Set Y1
and Y2
shift
controls to
the
mid
-position
between
their
respective
vertical
arrows.
(b)
Set the X shift
control
to
its
mid
-position
between
the
horizontal
arrow.
(c)
Set the
LEVEL
control
clockwise
to B/L
position
and
B/L
slide
switch to
ON.
(d)
Set the TIME/CM
switch
to
1
msec/cm
and
TB
slide switch
'to
X1.
(e)
Switch
on
by rotating
BRILL control
clockwise from its OFF position. The
indicator
lamp
will
light up.
Allow
a
short time for the
cathode ray tube to
warm
up, when two
traces
shou
Id
appear
on the
screen.
(f)
Adjust
Y1,
Y2
and X
shift
controls
for
suitable
positioning of the displays.
Adjust the
BR I LL control
for
required intensity
and the
FOCUS
control
for a
sharply
defined
trace.
Y
CHANNEL MODES
The
dual
trace mode
is
obtained
with
the
TRIG
SOURCE slide switch in the
Y1
or Y2
position.
At
sweep
speeds
between .5 sec/cm
and 2 msec/cm
the
vertical
amplifiers operate in the chopped
mode
and
are
switched
at 200kHz
approximately. For sweep speeds
between 1 msec/cm and
1
usec/cm the
alternate sweep mode
is
employed.
The appropriate
mode
is
automatically
selected
by
the T I M E/CNl
switch.
Single
trace
Y2 only operation
is
obtained with
the
TRIG
SOURCE
slide
switch in
the
SB Y2
position.
This
is
useful
to
obtain
maximum brightness at high
sweep
speeds, particularly
when
the
trace is
expanded X10. With the Y1
X10
output
connected
to the
Y2 input a
maximum sensitivity
of
1
mV/cm is
obtained
for
signals
applied to the Y1
input. A
co
-axial
lead
should be
used
for inter-
connecting
the
two amplifiers and
also to the input
connector of Y1 so that hum
pick-up is
eliminated.
X -Y
operation is
obtained
when
the
TRIG SOURCE
slide
switch is
also
in the
SB
Y2 position.
This is
also designated
(X).
When the TIME/~M switch is
set
to
X
-Y horizontal
deflection is
obtained
from
signals
applied to the Y1 input connector.
Y
CHANNEL INPUT
COUPLING
The signals
applied to
the Y1
and
Y2 channels
are connected
to
the input
attenuators over 3
position
slide switches
with
the
following functions: —
(a)
DC
connection
direct
to
the
attenuator.
(b)
AC
connection
to
attenuator through 0.1 uF 400V
capacitor.
(c)
With
the switch in
its
mid
-position the
applied
signal is
open
-circuited
and the input to the
-
amplifier grounded.
This
provides a
base line
reference
at 0 volts.
NOTE:
When examining the low amplitude signal
superimposed on
a
high DC voltage the AC
coupling
should
be
used. This
enables
the display
to be viewed
at
high
sensitivity
settings of
the
attenuator
where otherwise it
might not be
possible
to position the
trace on
the
screen.
TIME
BASE
In
addition
to
selecting
sweep
speeds the TIME/CM
switch also
determines
the mode of
dual
trace
operation, as
described
above.
In the
X
-Y
position
the
time base
is
turned off
and
horizontal
:
deflection is
obtained from signals applied to Y1
when
the
TRIG
SOURCE
switch is
in the
SB
Y2
(X)
position. s
5

•
Sweep
speéds
from .5
sec/cm to
1
usec/cm
are
selected by the
TIME/CM
switch
in
a 1,
2,
~5
sequence
covered
by 18
positions.
The sweep
speeds
are
correctly
calibrated
when
the TB
slide
switch is in the
X1
position
and the VELOCITY control
rotated fully
clockwise
to
its
CAL
position.
Counter -clockwise
rotation of_ the
VELOCITY
control
provides
continuously
variable
reduction of
sweep
speed
over
a
range of 3:1
approximately,
thus providing
continuous coverage
and overlap
between
sweep speeds.
With
the
TIME/CM switch in
the .5 sec/cm
position
and the
VELOCITY
control
fully counter-
clockwise -the
slowest sweep
speed
of
1.5
sec/cm
is
obtained.
With
TB
slide switch
set
to X10
the
trace
is
expanded
by a factor
of
10
and
the
trace
becomes
effectively 100 cm in
length.
With
the
TIME/CM
switch
in
the
1 sec/cm
position
the
highest sweep speed
of 100
nsec/cm is
obtained.
Any
portion
of the
expanded
sweep may
be
viewed
on the centre of the
screen
by
operation
of
the
X
shift control.
X
-Y
MODE
The setting up
for this
mode
of
operation is
as
set out
above.
It
is
important
that the
Y1
and Y2
input
couplings
should be in
the
same
position, both
DC
or
both
AC, as
disparate couplings will
cause
phase
shift
of
the
vector
display,
particularly
at
low frequencies. The
wide bandwidth
of the X
deflection channel
ensures that
phase shift is
insignificant up
to
20
kHz,
where
it
is normally of
the -
order
of 0.5 degree.
The X shift
control
positions
the
trace
in
the
horizontal
direction and the
Y2 shift
control
in
the
vertical
direction.
The Y1 shift control is
inoperative.
TRIGGER
The time
base may
be
triggered
from
the internal
sources Y1 or
Y2
when the trigger
mode
polarity
switch is in
the I
NT
position.
With this
switch
in the EXT position
and
a
signal
applied to
the
external
trigger input
socket the
time
base is
triggered
from the
external
source.
Triggering
may
be
from the
positive or negative
going
slope of the
triggering waveform.
the
option
being
provided
by
the trigger mode
polarity
switch.
When the B/L
slide switch is
in the OFF position
the
screen will remain
blank in the absence
of a
triggering signal. With
a
triggering
signal
present
the
LEVEL control
may
be
rotated to select the
position on
the
display
at
which
the time base
commences.
This mode
of operation
may be
preferable
for
examining
complex waveforms
and very
low
frequency
displays,
particularly if
ripple or noise
is
present
on the
signal.
It is
expected
that normally the
B/L ON
mode
will
be
used
when, with the
LEVEL control
rotated
fully
clockwise to
the B/L
position,
a bright reference
line
will
be displayed
in the absence
of a
triggering signal
at
all
sweep
speeds. With
a
triggering
signal
present
the LEVEL
control
may be
operated
to obtain
a
stationary trace triggered
at
the desired
level.
If the time base
is
required
to
free
run continuously
the
LEVEL.control
should
be left in the
B/L
position.
The
triggering signal
is coupled to
the trigger amplifier
over
filter networks which
modify its
frequency response
so that it
becomes
suitable
for
the type
of signal being displayed.
The filters
are
selected
by a
3
position
switch to provide
AC,
AC
fast
or TVF modes
of operation. Their
functions
are
as follows: —
AC: The
trigger circuit
bécomes
a
wideband amplifier
suitable
for
most
kinds
of
signal.
AC fast: The
filter
rejects low
fr-equencies.
suitable
for
triggering
high
frequencies and
complex
waveforms,
especially
when high
ripple
or
noise
is present.
TVF:
The
filter
rejects
high
frequencies
and
its
cut-off
is
designed to
accept
frame
synchronising
signals of a
TV
video
waveform
and
reject
the line
frequency
component. It is also
preferable
to use
this
mode for
signals
below
about
15
Hi.
I
6

ADDITIONAL
FACILITIES
CAL —
This
socket
provides
a DC
coupled
positive going square wave
at
line
frequency,
with an amplitude
of 60 mV
f
2%.
This
provides
a vertical
deflection
of 6 cm when
applied
to
the Y1 or
Y2 inputs when
the
attenuators are set to
10
mV/cm,
and enables the calibration ~ be checked.
The
attenuator coupling
should be in the
DC position to
avoid
slope
at
the
top
of
the square wave.
X
OUT —
This
socket is
DC
coupled to the time base circuit
and
provides
a
positive
going
ramp output of
approximately
10 volts.
The
output
impedance
is 15Kohms.
GATE
o/p —
This
outlet is
connected to the time base bistable to provide a
positive going
square
wave
of 17
volts approximately
at
sweep
repetition
rate. It should be
used
for setting up
the
probe
and a
protruding pin is
fitted for ease
of
connection.
For
this
purpose the TIME/CM
switch should be set to
1
msec/cm,
the
Y1
and
Y2
couplings
to
DC and the attenuator
to .1
V/cm.
The probe
capacitor
should be adjusted so that a
straight horizontal
line appears
on the
screen.
Z
MOD —
This
socket is
AC coupled to the grid of the
cathode
ray
tube and
is
mounted on the rear
panel._
An
input
of 10V
produces
visible
modulation.
Y1
X10
— Signals
applied
to
Y1 input are
amplified
X10
and are
AC
coupled
to
the Y1
X10 output connector
at an output impedance of
approximately 50 ohms.
Maximum output
5V
approximately,
bandwidth
2Hz-5mHz.
7

DESCRIPTION OF
CIRCUIT
VERTICAL AMPLIFIERS
The two
vertical amplifiers, Y1,and Y2, have identical circuits
except that
Y1
also contains
a
X10
pre -amplifier
to
provide a
1
mV/cm facility
when
cascaded
into
Y2.
The
following description
of
the Y1 channeÍ
also
applies to Y2, the
component
references in
brackets being
the complement
of
thosé in
the
Y1 channel.
The X10 pre
-amplifier will be dealt
with separately.
Signals from
the attenuator are fed
to terminal
4
(11)
and via the
protection circuit
R107/C104
(R
168/C119)
to the gate of the
F ET T R 101 (TR 116) : diodes
D
101 /102
(D 107/108)
prevent .
excessive voltages being
applied
to the gate.
TR101
(TR116) is connected
as a source follower and
is do
coupled
to TR105 (TR120). The FET TR102
(TR117) is also connected
as a
source
follower
and
is
coupled via
terminal
5 (15)
to the trigger
channel selector
switch
S6.
TR 104/TR 105
(TR
119/TR 120)
are
connected
in a
low
gain long tail pair
configuration with frequency compensation
applied to
the emitter.
Vertical shift is
applied to
the base
of
TR104
(TR119} over the
emitter
follower
TR103 (TR118). The
collectors
of TR104/TR105
(TR119/TR120) are do connected to the
bases
of TR110/TR111 (TR112/TR113),
the do
level being set by
R121 (R180). TR110/TR111
(TR112/TR113)
are
connected
as a long tail
amplifier with
common collector
loads R148/R149,
the overall gain
being set by R147
(R151).
Frequency
compensation is
effected by
C113/C114
(C115/C116).
Dual
trace operation is
obtained
by
switching
the
collector
circuits of
TR110/TR111
(TR112/TR113)
over diodes
D111
to
D114 (D115/D118), the
chopped
or alternate
sweep
mode
being
determined
by
the•setting of the TIME/CM
switch S12.
The circuit
operates in the chopped mode for
sweep
speeds
up
to
2msec/cm
and
in the
alternate sweep
mode from
1 msec/cm
to
1 usec/cm. The switched
outputs
from
the collectors of TR
110/TR 111
(TR 112/TR 113)
are
sequentially
connected tá the
bases of
emitter followers TR114/TR115 and,
via
terminals
7 and
8, to the
vertical
output
amplifier.
The vertical
amplifier
is
assembled
on a
separate
printed
circuit board mounted close to
the
base
of
the cathode ray
tube,
its input
terminals
19 and 20
being connected to the
differential output
from the pre
-amplifier described
above.
TR'301/TR302/TR303/TR304
are connected
in a
long
tail
pair
cascode configuratïon with
frequency
compensation
effected
by C302/C303 and C304/R316.
The parallel combination of R301/R302
and
R303/R304
provide loads for the collectors of
TR303/TR304
which are do
connected to the vertical deflection
plates
of
the cathode
ray
tube, the
overall
gain of
the complete
vertical
amplifier system being set to 10mV/cm by adjustment of R313.
The mean do
voltage
at
the
collectors of TR303/TR304
is set by R315
to
be
close
to
the
mean do
voltage applied to the
horizontal deflection
plates
to ensure
optimum geometry
of the display and
minimum
deflection de
-focussing.
X10 PRE -AMPLIFIER
Signals appearing at the source
of FET
TR301
are do connected to the base
of
TR106.
TR106/TR122
are connected
in a long
tail
pair
configuration to
provide
a single ended output
in
the
correct
phase
from the collector
of TR122
at a do
level set by
R129. Frequency compensation
is
provided by
~C106.
The
collector of TR122
is ac coupled to the BNC
connector SKc
via the
emitter follower
TR108.
With signals applied to
the
input of Y1
and
SKc connected to
the
input
of Y2 a sensitivity
of
1mV/cm may
be
obtained.
R139 is
fed
via
terminal
9 to
the TIME/CM switch
S12
and
is
adjusted
to provide
a sensitivity
of
10mV/cm
of horizontal deflection
when
S12
is in
the
X -Y
position. In
this
latter
condition signals applied
to
Y1 provide
horizontal
deflection
and those to Y2
tho
vertical
deflection.
s

BEAM
SWITCH
TR124/TR125
comprise the
beam switch
bistable
and
will operate in
three
modes
as
determined
by
the
setting of
the TI M
E/CM
switch S12
and
the
trigger channel
selector
switch
S6.
For
sweep
speeds
0.5sec/cm to
2msec/cm R200/R205 are
grounded
over
S12
and
the
circuit
becomes
astable,
switching
diodes
D111
to D114
and D115 to D118
at
200
kHz approximately.
The instrument is
now
operating
in
the
chopped mode. At
sweep speeds
above
2msec/cm the
operation is
in
the
alternate
sweep
mode:
R200/R205 are
returned to + 20V
over
S12
and
the circuit now becomes
bistable. Switching
will
now
occur only
at
the
end
of
a sweep,
when
TR123
is
turned
off by a
pulse from the time base
circuit.
The switch
S6
provides
the third
mode
of
operation —
Y2
only. In the
chopped and alternate
sweep
modes
the
collector
of
TR125 is
connected
to the
collector of
TR124
over
S6. In
the Y2
only position
of S6
the
collector of TR
125 is open
circuited
and
connected
to +
20V.
The
output from
the beam
switching
circuit is
fed over R196 to
D111 to
D114
and over
R209
to
D115 to
D118.
When
the
Y1
channel
is being
displayed
the shunt
diodes D111/D114
are
turned off
and
the series diodes
D112/D113
conduct, thus
connecting the
collectors
of TR110/TR111
to the
emitter followers
TR114/TR115
and
thence
to the
vertical output amplifier.
The
display exists for
the
duration of
a chop or alternate
sweep
cycle, at the end
of which diodes D111/D114
are caused
to
conduct, raising
the cathodes of
D112/D113
to a
voltage
higher than that of their cathodes. The
sequence of
operations
described for the
Y1 channel
now
occur in
the Y2
channel,
shunt diodes
D117/D118
and series diodes D115/D116
operating in a
manner
similar to their complements in
the
Y1
channel.
TRIGGER
CIRCUIT
The trigger
polarity
switch
S9 selects
signals from the
internal
sources Y1 or
Y2 over S6, and
from an
external
source over socket
SKg.
The
selected source
signal is
fed to the
trigger amplifier
comprising
TR402/TR403/TR404.
The output from
TR403 is taken to the trigger
coupling switch where
filtering
is
introduced so that the circuit will
respond to
ac, ac fast
or
TVF signals.
S10,
the
trigger
coupling
switch, connects trigger signals
to the base
of
either
TR405 or
TR406 ovér S9,
which
determines
the polarity of the
trigger
slope.
TR405/TR406 are connected
as a long
tail
pair
amplifier,
and
an
adjustable
bias is
applied to the bases
from
R4
to
control the
level on
the
slope
waveform at which
the time
base is
triggered.
The
output
from
the
collector
of TR406 is passed to
the
Schmitt
trigger TR407/TR408,
where fast edges are developed to
trigger the
time base
bistable
TR409/TR410.
TIIl1E
BASE CIRCUIT
The circuitry
around
TR412/TR413/TR414/D406
develops a constant voltage
across
the VELOCITY
control
R3
and
R460/R461/R462. The slider of
R3 is
connected to
timing
resistors as selected by
the
TIME/CM
switch
and
a
constant current,
which is
independent of
voltage,
produces a linear charge
in
the selected timing capacitor. The time base is
calibrated
with R3
in
the
CAL position and
this
control
may
be operated to
provide a
continuous
reduction of sweep speed
over a ratio
of more than
X3:1.
Before the commencement of
a sweep TR409 is
on and
TR410
off,
causing
TR411
to
saturate
thus
effectively
short circuiting the
timing capacitor.
A negative
going pulse from
the
Schmitt
trigger
is
connected over C407/D401
to
the base
of
TR409, turning
it off. TR410 is
now
turned
on and
TR411
turned
off, removing the
clamp
across
the timing
capacitor which
now
begins
to
charge.
The
positive
going linear ramp
voltage thus
produced is
connected to the
horizontal
output
amplifier
over
the
cascaded
emitter follower
circuit comprising
TR412/TR413/TR414.
As
the ramp
voltage at
the
emitter of
TR414
rises
D404/R446/R447 pass a feedback
voltage
to
D401
9

to
prevent
further
trigger
pulses reaching
the base
of
TR409. To
ensure complete freedom
from
residual trigger
breakthrough
the Schmitt circuit TR407/TR408
is biassed off by a
positive
voltage
applied to
both
emitters for the
duration of
the
sweep
over
TR401/D407. The
junction
of R446/R447
is
connected to the
hold -off
capacitor as
selected by S12, and in
the
course
of
a
sweep
this
charges
to
a
positive voltage. The final ramp
amplitude at
the
emitter of
TR414
reaches
approximately +
10V,
at
which
point feed back
from the
junction
of
R449/R450 turns
on TR409. The bistable
TR409/TR410
J
now
reverts to its original quiescent
condition
and
will accept
the next
trigger pulse
after the
hold off
capacitor has
discharged
through
R446/R448.
The ramp voltage at
the
emitter
of
TR414 is
connected
over
R451
to
the
output
socket
SKf.
The
emitter of TR401
is connected
over
R457 to the
GATE 0/P
connector PLa.
BRIGHT LINE CIRCUIT
With
the
B
R I G HT LINE
ON/OF F switch S8
closed
the
screen
will remain
blank
until the
arrival of
a
trigger
pulse
initiates
a sweep:
the
switch
is now in the
bright line
off
position.
With S8
open (bright
line on) a sweep is automatically initiated
in
the
absence
of a
trigger
signal or one
that
is
too
small
to
actuate the Schmitt trigger.
On
the
arrival of
a
trigger
signal
operation
of the
LEV E L
control wil I
lock the display at any selected
point on the slope of the
triggering
waveform.
The
action is as
follows: with
a
trigger signal
present
the square wave
at the
collector
TR408 is
coupled
over R452/
C408
to D402,
where
restoration
produces a negative
going
signal with respect to
the negative
rail.
The signal
now appearing
at the
emitter of TR419 is integrated
by
R453/409 and
produces
a do bias
to
hold
off
TR420. The
time
base is not affected by
this
condition. In the
absence
of a
trigger
signal
or
one that is too
small,
the
bias is removed.
The emitter
of
TR419 rises and
turns
on TR420.
R455 is
now
virtually connected
between the
negative
rail
and the cathode
of D401,
causing the hold
off
capacitor
to
be
discharged
rapidly: TR409
now
turns off
and
a sweep
is initiated.
At the end
of
the
sweep the
charge
accumulated
on the hold
off
capacitor
is again
removed by the
action
referred to and
the cycle is
repeated,
providing
successive sweeps which
produce a
bright line at
all
sweep
speeds.
HORIZONTAL OUTPUT
AMPLIFIER
The
ramp
or X
-Y signal at the
emitter
of TR414, as
selected
by the
TIME/CM
switch
S12, is fed over
R432
to the
base of TR415.
TR415/TR416/TR417/TR418form along
tail pair cascode
amplifier,
with
the
horizontal shift
voltage applied to the base
of
TR416. Again
of X1 or X10
is
selected by
S7
which introduces
R450/R451 (X10)
in
shunt with
R458/R459
(X1) between the
emitters of TR415/
TR416.
The
differential output
from
the
collectors of TR417/TR418
ís do connected
to the
horizontaF
deflection plates of the
cathode
ray tube over R441 /443.
X
-Y MODE
In the
X -Y mode the
vertical
deflection
with a sensitivity of
10mV/cm to
50V/cm
is provided by the
Y2
channel.
With S6
in the
(X)
position and
the
TIME/CM
switch S12 in the X
-Y
position the output
from the emitter
of TR108
is
do
connected to
the
input of
the
horizontal amplifier.
In
this condition
the
gain of the
horizontal
amplifier
is
automatically
set to
X10 by contacts on
S12, and
signals
applied
to the
Y1
channel provide
horizontal deflection
with a
sensitivity of
10mV/cm
to
50V/cm.
Position-
ing df the
tràce in the
horizontal
direction
is
by the
horizontal
shift
control R5, the
Y1
shift
control
being
rendered
inoperative.
In the
X
-Y mode the
time
base
is
stopped
b_y removal of the
timing circuit
and
the
application
of
a
negative
voltage to
D401, which
causes the cathode
ray tube
to
remain
perm-
anently unblanked.
BLANKING
The
collector
of TR409
is
connected
to
the
base
of
TR423
ovér the emitter
follower
TR422.
In
the 7
~
~
~.
~
~
~
,,
~
.~
~

absence of a sweep
and
for the duration of
the fly
back
retrace
the
collector
of TR409 is virtually
at
ground
potential
and
the
voltage at the
collector
of
TR423 rises
to
approximately 120V.
This collector
potential is
connected
to
the
beam blanking
electrode
of
the
cathode
ray
tube ; and blanking occurs
With
the
commencement of
a
sweep
the
potential
at
the collector
of
TR409 rises to approximately
20V, the
collector
voltage of TR423 drops to a
very
low value and the
cathode ray tube
is
unblanked.
Pulses
from
the
beam
switch
circuit are
connected
to
the
base of TR421, the
collector
of
which is
connected
to
the junction
of
R473
and the
base
of
the
emitter follower
TR422. This circuit
provides
do
coupled
chop
transition blanking.
CALIBRATOR
The
base
currerit of
TR126 is
de"rived from
R217/D127 connected to the +
20V'line.
The
anode of
D126
is
connected to
the junction of
R217/D127,
its
cathode
being connected to
an ac
voltage
at line
frequency
via terminal
17. Positive
excursions
of the ac.voltage saturate
TR126
and
negative voltages
turn
it
off. The
square
wave
thus
produced is
fed
to
the CAL output socket
SKd, its amplitude being
adjusted
to
60mV
± 2%
by
R215.
POWER
SUPPLIES
The
power
transformer T1 has primary windings
to
accept síx supply
voltages
at
45-44Hz.
The
appropriate
connections
are
shown in
the
MAINTENANCE
section of
this manual.
All internal power
supplies
are
derived
from T1, its
secondary
providing the
following
windings: -
6.3V
(for
c.r.t.
heater) 22-0-22V,
150V,
1,000V & 1,200V. .
The 150V
supply
is rectified
by
MR1
and
after
smoothing by
C36
and
C37 provides
approximately
195V
do for
the collectors of the
high
voltage
transistors
feeding the
deflection plates
of
the cathode
ray
tube.
The 22-0-22V supply
is rectified by M R2
and smoothed by
C38 and C39 to
provide
approximately
26V
do
fot~ the +20V
and
-20V stabilised
lines.
Similar circuits are
used
in
both
the
+20V
and
-20V
lines,
and a description of the +20V
stabilised line
will
also
apply
to the
-20V stabilised line.
The
circuit complements
of
the
latter
are
given
in
brackets.
The high
gain amplifier,
comprising
TR424/
TR425
(TR427/TR428)
compares
the
reference voltage
of
the
Zener
diode
D407
(D408) with the
voltage at
the junction
of
R481/R482
(R487/R489), a
potential divider connected
between
the
emitter
of TR426 (TR429)
and ground.
Any
fluctuation of the
line
voltage
at the emitter
of
TR426 (TR429),
which
supplies
the
+20V
line,
are fed to
the báse
of TR425 (TR428) and an
inverted
amplified
correction
voltage
is
applied to
the
base of TR426 (TR429). The
voltage drop
across R479 (R486)
is pruportional
to
the
output
current
demand
at
the
emitter
of
TR426
(TR429).
Normally
this
voltage
is less than that across R478 (R484),
and D411
(D414)
is
biassed
off. If
the
output
current
rises
beyond the safe maximum
D411
(D414)
turns on and
takes
current
away from
the emitter of
TR424 (TR427).
As a result the voltage on
the collector
of TR425 (TR428).,
and
the
base and
emitter
of
TR426
(TR429),
drops,
and
the
current is limited to a safe value.
Two further +10V stabilised
lines are provided on
the
vertical amplifier
printed
circuit
board.
These are at
low
impedance, and
extremely
low ripple
content, for feeding
the
early stages of
the
vertical amplifiers. ,
Thë -EHT
line
is
obtained
from
the
1,000V supply
and
is
rectified by
MR401
and smoothed by C422
to C425 in series.
The do
output is taken over R493
to
the stabilising Zener
diodes
D418 to
D423
to provide
the
-EHT
line of
1, 068V.
The BRI
LLiANCE
control
is across
D418
which
provides
a total
swing
of
68V,
the slider of
the
control
being
returned
to
the grid
of the
cathode
ray tube to
control
the beam
current. Similarly,
the FOCUS is
taken
from an appropriate tapping on the Zener chain,
the slider being
connected
to
A2
of
the cathode ray
tube.
The final
accelerating potential
applied
to
the
PDA
terminal
is
2.5kV. This
is
obtained
from
the voltage doubler circuit
C426/C427, MR402/
MR403
and
C428/C427, which
is fed from
the
1,200V
supply.
The
rectified
and smoothed
do
output
is
connected
over R495/R496 to
the Zener diode chain D426/D438
to provide a
stable +
2.5kV line.
11

Z
MODULATION
Socket SKh on
the rear
is
connected
over
C40
to the grid
of the
cathode ray tube.
Signals applied to
SKh
and
its
adjacent ground
socket
SKj
produce intensity
modulation
of
the trace.
CATHODE RAY
TUBE
CIRCUIT
The
cathode
ray
tube
and
associated
circuitry
are shown in
Fig.
1.
The
BRI
LLIANCE
and
FOCUS
controls
are
connected
as
described
above.
A3 is
connected
to
R211
which
is pre-set during
test~for
minimum
astigmatism
and
optimum focussing
over the whole
trace. The
geometry
control
R213 is
connected to the electrostatic
shield
between
the
X and
Y
plates.
R213 is adjusted
during test to
provide optimum
geometry
of a
test raster. After deflection
by the
X and Y
plates
the
beam is further
accelerated by the 2.5kV applied
to
the PDA terminal of the
cathode
ray
tube.
12

MAINTENANCE
REMOVAL
OF
COVER
Remove
two
screws from handle
shrouds
and
three
screws at
the bottom
of each side
of
the
cover.
The
cover
can
now
be
I
ifted
off.
TRANSFORMER PRIMARY
CONNECTIONS
Thè
instrument
must
be
disconnected
from
the
supply
before
making
adjustments to the
transformer
primary.
Figure
4
shows
connections
to
be made to
suit supply
voltages in
the
range 95 to
260V.
After making
adjustments ensure
that
the
correct fuse is
fitted. It is
important
that the fuse
be
a
slow
blow type.
CRT
REPLACEMENT
1.
Remove bottom cover.
2.
Remove
CRT
base and
PDA
cap.
3.
Remove screws from rear
of CRT
support
clip and the clip
tightening screw.
4.
Push
CRT towards rear of
cabinet allowing the support clip to slide
along
the
mu
-metal
shield. With
the
CRT fully
removed from the
front support
bezel
it
can
be tilted at an
angle and removed
through
bottom of
the
cabinet.
5.
Remove
mu -metal
shield and internal
gun shield and
fit to the replacement
CRT.
Be
careful
nod
to knock the
mu
-metal
shield as this
may
impair
its magnetic
properties.
6.
Fit CRT
support clip, but do not
tighten. The
CRT can now be put back
in
position.
7.
Fit clip retaining screws
but do not fully tighten. Fit
CRT base and
PDA cap.
8.
Switch
on and rotate CRT so that a horizontal
line
display
is
true
to the graticule. Fit
clip
tightening
screw and
tighten
so that it grips the
mu
-metal
shield
without distorting it.
Tighten clip retaining screws.
FAULT
FINDING
Before attempting
to
locate a
fault
it
is
advisable to
check the
supply
line
voltages.
The
input
supply
voltage
should be
approximately at
the
centre of the
range for
which
the transformer is
adjusted.
The voltages
are measured
with
respect
to OV (chassis) and
are given in
Table
1.
LINE
MEASURED
VOLTAGE
+20V +19 to
+21 V
-20V
-19 to
-21
V
+195V
+180 to +210V
-1060V
-1000 to -1120V
+2500V
+2375 to +2625V
TABLE 1
i
13

Table
2
specifies
voltages
at
varíous points
on the circuits
and may
be used as a
guide to
fault
finding.
Wide
variations from
the
voltage
indicated
may locate a
fault
condition. in
general,
all
components
are
accessible
without removal
of
printed
circuit
boards. If
the
fault cannot be located
the
instrument
should
be
returned to the
manufacturers or
your
local
service
agent for repair.
Before
making
voltage
measurements
set
up
the
various controls as
follows: —
BR I
LL,
Y1
and
Y2
shifts, X shift
to
mid -position.
TRIG SOURCE slide
switch
to Y1.
B/L
slide switch to
ON
and LEVEL control
clockwise to
B/L.
TIME/CM switch to
X=Y.
Centre spot on
screen
with Y1,
Y2 and
X shift
controls.
LOCATION
Emitter of
TR109
and TR121
Collector
of
TR104,
TR105, TR119, TR120
Emitter
TR108
Col lectors
TR 124, T R 125
Collectors
TR303, TR305
Collector
TR403
Collector
TR404
Colléctor
TR405
Collector TR408
Col
léctor T R419
Collector
TR420
Emitter
TR414
Emitters TR415, TR416
Collector TR415, TR416
TYPICAL
VOLTAGE
+10V
(adjustable on
R141
and
R189)
+ 5.6V
+ 4.6V
+
13V
+ 100V
+ 17V
+11V
+ 17.5V
+ 20V
- 20V
-
6V
+
4V
+
4.5V
+
100V
,. TABLE 2
STABILITY OF
SUPPLY LINES
The
stability of
the
supply
lines can be
checked
by varying the
supply
input voltage ± 7'/2%around
the
centre voltage
of the primary
tapping in use. As an example
with the primary connected for operation
from 222 to
260V,
set up a
variable
autotransformer to
supply 240V ± 1%. With variations
of
input
supply
voltage
between
222 to
260V the
supply lines
should
not change by more
than
stated
in
Table
3.
LINE
+ 20V
- 20V
DEVIATION '
not
measurable
"
+,195V ~
7'h%approximately
-1060V
±
1 %
"
+2500V ±
0.5%
TABLE 3
SÉTTING
UP
&CALIBRATION
Test equipment
required:
1.
Multi
-range
meter
0 -
3kV
at
20,000 o.p.v. .
.
2. Sine/square
wave
signal
generator
10Hz - 100kHz.
3.
Oscilloscope
calibrator
providing accurate voltage and time
calibration
signals.
4. TV
video
waveform
generator.
5. Flat top
square
wave
generator
200 -
500kHz
providing output
of
60mV
into
50
ohms.
Rise
time
less
than
5nsec.
1

VERTICAL
AMPLIFIERS
Check that a
horizontal
trace on the CRT is true
to the
graticule. It
is
important that the
following
procedure be
carried
out in
the
order
specified.
Astigmatism
and
geometry: display
about 10 cycles of
a
1
kHz
sine wave.
I
n conjunction
with
the
FOCUS control
adjust
R211 for
optimum focus over
the whole
display, which
should
have an
amplitude of
about
ócm. Adjust
R213
for the best
compromise between horizontal and vertical
pin -
cushioning
and barrelling.
Re
-check
the focus and,
if
necessary,
re -set
R211
Sensitivity:
Switch Y1
and
Y2
attenuators
to
10mV/cm
and from
oscilloscope
calibrátor apply a
60mV 1 kHz
square
wave to both
channels.
Both channels
should deflect
to
exactly ócm. If
necessary
adjust
R147 (Y1)
and R151 (Y2)
to
achieve
this
result.
Calibrator:
Immediately
after carrying
out the above test
apply
CAL output to both channels —with
input
coupling set
to DC
—and check
that deflection is exactly
ócm. If
not adjust R215 for this
result
Attenuator
compensation:
using a IkHz
square
wave adjust each
step
of
the attenuators for
a display
free from
overshoot or
undershoot. At
each
step
the input
signal
should be adjusted to give a
display
of
about 5cm.
The
compensating
capacitors of
each attenuator
have identical layouts
—see
Fig.1
(c).
~
L
SETTING
10mV/cm
20mV/gym
50mV/cm
.1
V/cm
.2V/cm
.5V/cm
1
V/cm
2V/cm
5V/cm
10V/cm
20V/cm
50V/cm
ADJUSTMENT
no adjustment
adjust C16/C17
"
C10/C11
" C32/C33
" C12/C13
"
C8/C9
" C26/C27
no adjustment
if C12/C13
correct
" " C8/C9 "
adjust
C20/C21
no
adjustment if C12/C13
correct
" " C8/C9 "
Return
both
attenuators
to
10mV/cm
and
apply
600mV 1
kHz
square
wave to
each channel
in
turn,
via
10:1
probe. With the probe first
connected to the
Y1 channel
adjust the
probe
compensation
capacitor for
optimum square wave
response. Next fit
the
probe
to the
Y2 -channel
and,
if
necessary,
adjust C118 fór
optimum square wave
response. If this
cannot be achieved carry out the
above proced-
ure in
reverse order,
i.e.
setting up the
probe first
on Y2
channel
and
adjusting C102
for optimum
square
wave response from the Y1
channel.
Now
make
the.following
adjustments to the
input
attenuators
with
1
kHz
square
wave
applied via probe: —
.1
V/cm
adjust
C30/C31
1
V/cm
C24/C25
10V/cm
C18/C19
in each case the
displayed
signal
should have an
amplitude sufficient to permit
accurate adjustment
of
the
compensating capacitors.
Bandwidth:
Set TIME/CM
switch
to
1usec/cm
and
TB
slide
switch
to
X1. Apply
output from
flat
top 5nsec rise
time
generator, terminated 50
ohms,
to
the Y1 input with
the attenuator
set
to
10mV/cm. Adjust C113, C303, R316
for
optimum
square wave
response free from
ringing
and
overshoot. It is
important that the adjustments
be
made such that the leading edge is as
steep as
possible and free from
steps.
Transfer signal
to the
Y2 channel and adjust C116 for
optimum
response.
With both channels still
set to
10mV/cm
apply
to 100kHz
sine
wave to
the
Y1
channel
and
adjust
the
output from
the generator
to
give
exactly
ócm of
deflection.
Note
the
precise
output
from
the signal
generator and re -set
the generator to 15mHz
with precisely
the
same
output. The
resultant
display
should have a
minimum
amplitude
of 4.2cm,
corresponding to
-3dB.
Repeat
the above
test for
the Y2
channel.
NQTE: a
time
base setting
of
10usec/cm is
suitable
for
the above tests.
15

TIME BASE
CALIBRATION
Set
TIME/CM
switch
to
1 msec/cm and apply accurate
1 msec
time
markers to the
Y1 channel,
adjusting the
attenuator
for a
suitable
amplitude. Lock
signal
and adjust
F~459
so that each
marker
is
displayeciaccuratelyVat 1cm
intervals
on
the graticule.
Set TIME/CM
switch
to
10usec/cm
and
time mark
generator to
10usec.
Adjust C44
for exact
spacing of
time
markers. Check that
all other
sweep
speeds
are
within stated
tolerance.
TIME BASE
EXPANSION
Set up a
locked display of 1
msec/cm with TB
slide
switch in X1
position. Now
switch TB
slide
switch
to X10
and
apply
10msec time
markers
to the Y1 input. Adjust
R451 so that the
signal is
accurately
displayed
at 1
cm intervals on the graticule.
TRIGGER
SENSITIVITY
(1)•
With
trigger
coupling switch in AC
position
apply
a
10Hz
sine wave
signal
to the
Y1
input
and check
that the display can be
locked by the
LEVEL
control down to
an
amplitude of 2mm
approximately
in both
the
B/L
ON
and
B/L OFF
conditions.
(2) Apply
a SmHz signal with an
amplitude of 2mm
approximately
and
check that the
display
can be locked
as in (1)
above.
(3)
Carry out
the test
as in above but with an
amplitude
of 5mm
approximately. Increase the
input
frequency
to
15mHz
and check that the display
can
be locked.
(4)
Switch
to AC fast
and
apply
a
10kHz
signal
to give
a 5mm deflection. Check that it
is
difficult to lock this
signal.
(5)
Switch to
TVF
and
apply
a signal from
the video
waveform generator
with an
amplitude
of
about
2cm.
Check
that
the LEVEL contról can be adjusted to give a stable display
triggered
from the video
frame pulse.
(6) Apply
an
external
trigger signal
and
check that
it can
be locked
from a
1
V
input
over
the
range
10,Hz
to
15mHz.
X
-Y
OPERATION
Set
up
the
instrument for X
-Y
operation
and
apply
the
60mV
CAL signal
to the
Y1
input
with
input
coupling
set to DC.
Set the
Y2 input coupling
to
the ground
position. .Check thát the
two
spots
span
ócm
exactly
in
the
horizontal
direction: if
not
adjust R139
for this
result. Remove CAL
signal
and apply
a 10kHz
sine wave to produce a
horizontal
line
of
exactly
ócm. Note the precise output
from
the signal
generator
and
rë-set to
1 mHz
with exactly
the same output. The
resulting
line should
not
be less than
4.2cm
in length. This
indicates a 1 mHz bandwidth -3dB. A lire in excess of 4.2cm
indicates
a
still
higher
bandwidth.
Z
MODULATION
Set
Y1
attenuator to 5V/cm,-Y2
input coupling
to ground
position and TIME/CM
switch
to
1msec/cm.
Apply a 10V 1 kHz
square
wave
to
Y1
output and Z modulation
socket at rear of
instrument. Lock
the
Y1
display
and
then shift
off the
screen.
Centre
the Y2 display
and check
that the resultant
horizontal
line
is adequately
blanked at
normal
brilliance
levels.

PARTS LIST
COMPONENT
SPECIFICATIONS.
All
resistors carbon film
±
5% 1/3 watt, unless specified.
All
capacitors
paper,
ceramic
or
polystyrene
minimum
working
voltage
50V do unless
specified.
All
transistors as
specified,
except
that
suitable
alternatives
may be
used
in some instruments.
All Zener
diodes 300
milli
-watts
minimum,
unless
specified.
X
Board
MD
163
R401 47K
R446
1 K
R489
1 K3
R402
10K
R447 1 K
R490
10R
R403 1 K
R448 27 K
R491 47 K
R404
47R
R449 15K
R492 47
K
R405 4K7
R450 100R
R493
120K 1
watt
R406
100R
R451 100R
pre-set
R494
33K
R407~ 10R
R452 10K
R495 3M3
1 watt
R408
100K R453 1 M5
R496
100K
R
409 100
R
R454 1 K
R497
100R
R410 6K8 R455
10K
R498 ~
27K
R411
120R
R456 10R
R499
100K
R412 100K
2
watts
R457 10K
R
500
680
R413 330R
R458 1 K8
R414 10R
R459 1 K pre-set
NOTE:
R451
was 470R and
R472
R415 1 K
R460 56K 1 watt
was
100R on
some
models.
R416 4K7
R461 2M2
~
R417 1 K2
R462 3K9
C401 .01
u F
.•..
R418
1
K2
R463 1 K2
C402 680 p F
R419
47R
R464 27 R
C403
.1
u F
~
R420 47
R
R465'
3K3
C404 10
uF 25V Elect.
~
R421
270R
R466 100K
C405
22 uF 25V Elect.
R422 1
K5
R467 1 K8
C406
33 p F
,~,
R423
4K7
R468 12K
C407 6. 8 p
F
~
R424 3K3
R 469 47 K
C408 .01 uF
R425 1 K R470 3K9
C409
10 uF 10V Tantatum
R426 68K
R471 3K9
C410 220 p F
R427 47 R
R472 560R
C411 .01 u F
c -- ~
R428
R429
10K
2K7
R473
R474
10
R
10R
C412 .1
uF
C413 .1 uF
.~.
R430 1 K2
R475
22K
C414 .01 u
F
R431
~
39K
R476 15K
C415 33 pF
R432
100R
R477 15K 2
watts
C416 .01 u F
~
R433
1
K8
R478
82R
C417 .01
uF
R434
,--
1
K8
R479
5R6
C418 33 pF
R435
2K ±
2%
R480
47K
C419 27 pF
R438 100R R481 2K2
C420 22 p F
R439
~
1
K8 ,
R482
1 K3
C421
180
pF
R440
10K
2 watt
R483
, 10R
C422 2.2 u
F 450V E I
ect.
~
R441
100R
R484
82 R
C423 •
2.2 uF 450V
Elect.
-~
R442 10K
2
watt
R485
47K
C424 2.2 uF
450V
Elect.
.~.
R443
R444
100R
56K 1
watt
R486
R487
5R6 r
2K2
C425-
2.2 uF 450V
Elect,
C426
.02 u
F 1.5kV
~
R445 56K 1
watt
R488 100R' ~
C427
.02 u
F
1.5kV
,~
17

X
Board MD
163co~v.
*
suitable
alternatives
may
be used.
C428 4700 p
F
4kV
TR401
BSX20
C16
6-25
pF
C429
4700
pF
4kV TR402
BSX20
C18
4=20
pF
C430
1 uF 35V
Tantalum
TR403 BSX20
C20
3-10
pF
C431
.01
u F
TR404
BSX20
•
C22 39 pF
C432
6.8
pF TR405
BSX20
C24 4-20 pF
C433
.01
u F
TR406
BSX20
C26 4-20 pF
TR407
BSX20
C28 1000 pF
D401 1
N4148
TR408
BSX20
C30
4-20
pF
D402 11V4148
TR409
BSX20
C32 3-1C pF
D403 1N4148
TR410 BSX20
C34 .01
uF
D404 1 N4148
TR411
BSX20
D405
10V
Zener
TR412 BC212
D406
7.5V
Zener
TR413 BC212
Y2 Attenuator
D407 1 N4148
TR414 BC182
D408
6.8V Zener
TR415 BC212
R
15
500K
fi
1%
D409 1
N4148
TR416
BC212
R 17
1 M± 1%
D410
1N4148
TR417
BF258
R19 800K±
1%
D411
1
N4148
TR418
BF258
R21 250K ±
1%
D412
1
N4148
TR419
BC212
R23 900K ± 1%
D413
1N4148
TR420
BC182
R25 111 K± 1%
D414
1 N4148
TR421
BSX20
R27
990K ±
1%
D415
1
N4148
TR422
BSX20
R29 10K 1± 1%
D416
1 N4148
TR423
B
F258
R31 1 M±
1%
D417
1N4148
TR424
BC212
R33
1K± 1%
D418
68V
Zener
1 watt
TR425 BC182
R45
10R
D419
200V Zener 1
watt
TR426 BC301
D420
200V
Zener 1
watt
TR427
BC182
D421
200V
Zener 1 watt
TR428
BC212
C9
3-10
pF
D422
200V Zener 1
watt
TR429
BC303
C11 4-20
pF
D423
200V Zener
1 watt
C13
4-20
pF
D424
1N4148
X
Board MD163
C15
6.8 pF
D425
1 N4148
completely
assembled
'
C17
6-25 pF
D426
200V
Zener 1 watt
our Part No.
MD163C
C19
4-20 pF
D427
200V
Zener 1
watt
C21 3-10 pF
D428
200V
Zener
1
watt
C23
39 p F
D429
200V Zener
1 watt
Y1
Attenuator
C25
4-20
pF
D430
200V Zener
1 watt
C27
4-20 pF
D431
200V
Zener
1
watt
R
14 500K ± 1%
C29
10Q0
pF
D432
~200V
Zener
1
watt
R 16
1 M± 1%
C31 4-20 p F
D433
200V
Zener 1
watt
R 18 •
800
K± 1%
C33
3-10 p F
D434
200V
Zener
1 watt
R20
250K ± 1%
C35
.01
u
F
D435
D436
D437
D438
200V Zener
1
watt
200V Zener 1 watt
200V Zener 1
watt
200V
Zener 1 watt
R22
900K ±
1%
R24 111 K± 1%
R26 990K ±
1 %
R28 10K1 ±
1%
R30
1M±
1%
Y1
or Y2
attenuator
completely assembled
MD
162C
Frontpanel components
MR401
MR250 *
R32
1K± 1%
R1
1K Y1
shift
M R402
M
R
250 *
R43
10R R2
1
K
Y2 shift
M
R403
M
R250 *
R3
5K Velocity
C8
3-10
pF
R4
100K Level
C10
4-20
pF
R5 . ,
5K X shift
C12
4-20
pF
R6
1
M
Focus
C14
6.8
pF
R7
250K Brill
+S2
~
~
~
~
~
~
~
r
~
.~,
~
..~
~
~
~
1
~
C
C
..~
~
..~
~
.~
~
*~
-~
18
(1

D
D
D
C
--,
C
~
~
C
~
~
~
~
J
~
~
c
--,
~
~
~
R
8 47
l
n
Y
1
atten.
C44
6-25
pF
R9
47 In
Y2
atten.
C45 4.7
u
F
R
10 22K *
C46 .047
u
F
R11 22K *
C47
560
pF
R 12 100K 2W **
C48
560 pF
R12 4K7 **
D1 1N4148
**
R37
100K ± 1%
D2 1 N4148
**
R38
100K ±
1 %
D3 1 N4148
**
R39 300K ± 1 %
D4 1
N4148
*
~.
R39 500K ± 1 %
R
134
F~ 135
R 136
R137
R138
R139
R
140'
R141
R 142
R 143
2K7
1 K
pre-set
390R
10R
10R
4K7 pre-set
10R
10K
pre-set
10R
8K2
* were 27
K
on
some
models.
**
now mounted on
R40
1M ±
1%
R41
3M ±
1 %
R40
10K
R144
R145
R146
R147
330 R
330
R
180R
500R pre-set
X Board
M D
163
as
R412, R416 and
D5
1
N4148
R148
R149
2K7
2K7
D416, D417,
D424,
D425
Switch
completely
C1 560 p F
assembled
our
R150
R151
180R
500
R pre-set
C2 1
uF
Tantalum Part
TB/D 12 R152
330R
C3 6.8 pF *
R153
330 R
C4
.01 u F YBoardMD161 R154
8K2
C5
.01
u F R155
10R
C6
.1
u
F
400V
R 101
8k2
R 156
10R
C7 .1 u
F
400V
R102 4k7
pre-set
R157
10R
* now on X
board
M
D
163 as C432
N
1
120V
neon
R103 2K7
R104 100R
R105 10R
±
R158
R159
R
160
R161
R162
10R
10R
10R
4K7
4K7
Rear
panel
components
R
106
1M
1%
R
107
330K
R34
1M
R108
47
R
R163
4K7 pre-set
R35 1 K5
2W
R109
15K
R164
8K2
R36
1K 1W
R110
10R
R165
10R
R46
100K R111
6K8
R166 2K7
R112
10R
R167
1M ±
1%
C36 100 u F
275V
R113 3K9
R168 330K
C37 200 u
F
275V
R114 10R
R169
10R
C38
1000 u F 50V
R115 10R
R170 47
R
C39 1000
u
F
50V
R116
470R
R171
10R
C40
.02 1.5kV
R117
1K8
R172
15K
R118 470 R
R173
15K
M R
1
W006 *
R119 470R
R 174
10R
M
R2 W004 *
R120
47 R
R175
3K9
R121 4K7
pre-set
R176
10R
FS
1 300 mA
or 600 mA
R122
4K7
R177
10R
slow blow fuse
R123 100 R
R 178
10R
R124 100R
R179
4K7
T1
TR/D12
R
125 2K7
R180
4K7
pre-set
*
mounted on
T1
R126 180R
R
127
4K7
pre-set
R181
R182
470R
470 R
R128
100
R
R183
470 R
Time/cm
switch
R
129
4K7
pre-set
R184
47 R
R130 1K2
R
185
1 K8
C41
1
uF ±
1%
R131 10R
R186
10R
' C42
.01 uF±
1%
R
132 2K4
R187
10R
C43
68
pF
R
133 10R
R188
6K8
19