Philips PM 3266 - Page 28

28
AC,
0,
DC
{SI
7,
SI
8)
AC
position
0
position
DC
position
A, 1 Mfi//15pF
(X3)
B, 1 Mn//15
pF
(X4)
2.2. 1.2.
Horizontal
channels
DEL’D TB,
ALT
TB, EXT X DEFL,
MAIN TB
(S2)
DEL'D
TB depressed
ALT TB depressed
EXT X DEFL
depressed
MAIN TB
depressed
POSITION
TB MAGN
(R2,
S3)
MAGN (V3)
X-AMPL,
HOLD-OFF
(R18)
TRACE SEP.
(R6);
Signal
input
coupling;
3-way
switch
Coupling
via
a
blocking
capacitor
Connection
between
input
circuit
and input
socket
is
interrupted
and the
amplifier
input
is
earthed
to establish
a reference.
Direct
coupling
With
no
button
depressed,
the
circuit
operates
effectively
as
if the
AC
button is
depressed.
When
viewing
long
duration
pulses
or d.c.
levels
of
waveforms,
the
DC
position
should
be selected.
For
a.c.
waveforms
with
large
d.c. levels,
the
AC
position
should
be selected.
BNC input
socket for
channel
A.
BNC input
socket for
channel
B.
Horizontal
displaymode
or deflection
controls; 4-way
push-
button switch.
The
horizontal
deflection voltage
is supplied
by the delayed
time-base
generator.
The
horizontal
display is switched
over
from the main time-
base to the delayed
lime-base
al
the
end
of
every
cycle of the
main
time-base generator.
Not functioning
when
TRIG VIEW is
depressed
or
when
the
delayed
time-base is switched
to OFF.
Horizontal deflection is achieved
by a
signal applied
to
the
external input socket
(X7)
of the horizontal amplifier,
by
the
channel
A or
B signals, the composite
signal,
or by a
mains-
frequency (LINE) signal, depending on the TRIG or X DEFL
push-button
(S22)
selection.
The horizontal
deflection voltage is
supplied
by the
main
time-base
generator.
A part of
the trace is
intensified
(except in the
OFF position
of
the TIM E/D IV switch of the delayed time-base generator).
No
push-button depressed
is effectively the
same
as
MAIN
TB
depressed.
Continuously variable control giving
horizontal shift
of the
display; incorporates
a push-pull switch for
increasing
the
horizontal
deflection coefficient by
a
factor of 10
(PULL FOR X10).
A pilot lamp indicating
that
the
XI
0
magnifier
is in operation.
Continuously
variable control of the
horizontal deflection
coefficients when using
external
X
deflection.
In the case of
X
deflection
by
the main time-base,
this control
can be used
to
increase the
sweep hold-off time.
Continuously variable preset
control of the vertical space
between the
two
time-base
displays in the
ALT TB
mode.
2.2. 1.3. Main
time-base
generator
LEVEL-SLOPE
(R7,
S7)
NOTTRIG'D
(V2)
Continuously variable control for selecting
the level of the
triggering signal
at which
the
time-base generator
starts.
This
control
incorporates a push-pull switch
that enables choice
of
triggering on either the positive- or
negative-going
edge
of
the triggering signal
(IN
+, OUT
—
).
Pilot lamp
indicating that the
time-base
generator is
in
the
waiting
position.