Element
Function
.
COMP. TESTER
Switch to convert oscilloscope
(pushbutton switch)
to component tester mode.
Y-POS.I
Controls vertical position
(knob)
of channel I display.
GD
−−−−−
AC
−−−−−
DC
Selects input coupling of CH. I
(pushbutton switches) vertical amplifier.
DC = direct coupling
AC = coupling via capacitor
GD = signal disconnected
from input,
Y amplifier input grounded.
INPUT CH I
Channel I signal input.
(BNC connector)
Input impedance 1M
Ω
II20pF.
INVERT CH I
Inversion of CH. I display.
(pushbutton switch)
In combination with ADD button
= difference CH. II CH. I.
VOLTS/DIV.
Channel I input attenuator.
(12 position
Selects Y input sensitivity
rotary switch)
in mV/div. or V/div.
in 1-2-5 sequence.
VAR. GAIN
Fine adjustment of Y amplitude CH. I.
(knob)
Increases attenuation factor
min. by 2.5 (left hand stop).
For amplitude measurement must be
in CAL. position (right hand stop).
CH I/II-TRIG. I/II
No button depressed: CH. I only
(pushbutton switch)
and triggering from channel I.
When depressed, channel II only
and triggering from channel II.
(Trigger selection in DUAL mode).
Y MAG. x5
When depressed, increasing of
(pushbutton switches) Y-sensitivity (CH I or CHII resp.) 5 fold
(max. 1mV/div.)
DUAL
Button released: one channel only.
(pushbutton
Button depressed: channel I
switch)
and channel II in alternating mode.
CHOP.
DUAL and ADD buttons depressed:
CH. I and CH. II in chopped mode.
ADD
ADD depressed only: algebr. addition.
(pushbutton switch)
In combination with INVERT:
difference.
OVERSCAN
Direction indicators.
(LED indicators)
Illuminated when trace passes
vertical screen limits.
VAR. GAIN
Fine adjustment of Y amplitude CH. II.
(knob)
Increases attenuation factor
min. by 2.5 (left hand stop).
For amplitude measurement must be
in CAL. position (right hand stop).
VOLTS/DIV.
Channel II input attenuator.
(12 position
Selects Y input sensitivity
rotary switch)
in mV/div. or V/div.
in 1-2-5 sequence.
INVERT CH II
Inversion of CH. II display.
(pushbutton switch)
In combination with ADD button
= difference CH. I CH. II.
AC
−−−−−
DC
−−−−−
GD
Selects input coupling of the CH II
(pushbutton switches) vertical amplifier. Specs see
.
INPUT CH II
CH. II signal input and input for
(BNC connector)
horizontal deflection in X-Y mode.
Y-POS.II
Controls vertical position
(knob)
of channel II display.
Inoperative in X-Y mode.
POWER
Turns scope on and off.
(push LED)
LED indicates operating condition.
INTENS.
Intensity control
(knob)
for trace brightness
TR
Trace rotation.
(potentiometer;
To align trace with horizontal
adjustment with
graticule line. Compensates
screwdriver)
influence of earth's magnetic field.
FOCUS
Focus control for
(knob)
trace sharpness.
X-MAG. x10
10:1 expansion in the X direction.
(pushbutton switch)
Max. resolution 10ns/div.
X-POS.
Controls horizontal
(knob)
position of trace.
HOLD OFF
Controls holdoff-time
(knob)
between sweeps.
Normal position = full ccw.
XY
Selects X-Y operation,
(pushbutton switch)
stops sweep.
X signal via CH. II.
Attention! Phosphor burn-in without X signal.
TRIG.
Trigger selector:
(lever switch)
AC
: 10Hz
−
100MHz.
AC-DC-LF-TV-
~
DC
: DC
−
100MHz.
LF
: DC
−
1.5kHz.
TV:
Triggering for frame and line.
~
: Internal line triggering.
TR
LED lights, if sweep is triggered.
(LED)
ALT.
Triggering alternates between CHI and
(pushbutton switch)
CHII in alternating DUAL Channel mode
only.
SLOPE +/
−−−−−
Selects the slope of the trigger signal.
(pushbutton switch)
+ = rising edge;
−
= falling edge.
TIME/DIV
.
Selects time coefficients (speeds)
(rotary switch)
of timebase,
from 0.2s/div. to 0.1µs/div.
Variable
Variable adjustment of timebase.
timebase control
Decreases X deflection speed
(center knob)
at least 2.5 fold.
For time measurements
turn to right hand stop.
TRIG. EXT.
Button released = internal triggering.
(pushbutton switch)
Button depressed = external triggering,
trigger signal via TRIG. INP
.
AT/NORM.
Button released = autom. triggering,
(pushbutton switch)
trace visible without input signal.
Button depressed = normal triggering
with LEVEL adjustment
.
LEVEL
Adjustment of trigger level.
(knob)
TRIG. INP.
Input for external trigger signal.
(BNC connector)
(Pushbutton TRIG. EXT.
depressed.)
CAL. 1kHz/1MHz
Selects calibrator frequency.
(pushbutton switch)
Button released: approx. 1kHz,
Button depressed: approx. 1MHz.
0.2V-2V
Calibrator square wave output,
(test sockets)
0,2V
pp
or 2V
pp
.
COMP. TESTER
Connectors for test leads
(4mm jacks)
of the Component tester.
3
1
2
Element
Function
22
21
23
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
16
17
14
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
Front Panel Elements HM 303
(Brief Description
-
Front View)
