BK Precision 1405 - Trace Rotation Adjustment; SWEEP VARI;EXT Gain; Effects of HOR Gain Adjustment; Alternate Method

ADJUStrMENTlI
b
Fig.
7. Effeets
of HOR GAIN
Adjustment
VR104.
SWEEP
VARI/EXT
GAIN eontrol
fully
eloekwise.
V
ATT switeh
to
GND.
?
POS to eenter
the
traee vertieally.
2. Apply
a
ealibrated
3
V
p-p
sine wave
or
square wave at
1
kKz
(with
no de offset)
to the EXT
SYNC/HOR
INPUT
jaek.
Conneet
the signal eom
mon
to the
J
jaek.
3. Adjust
HOR GAIN
trimmer
VR102
for a
horizontal
defleetion
of
10
divisions.
VR102 is aeeessible
through a
hole in the
bottom
of the ehassis
(see
Fig.
1). If the
ease is removed,
VR102
is loeated
as
shown
in
Fig.
6.
Alternate
ilethod
This
method
of adjustment
sets the sweep
length for
10 divisions horizontal
defleetion,
but
external
horizontal operation
is uneali-
brated"
The effeets
of HOR GAIN
adjustment
are shown in
Fig. 7.
1.
Set
oseilloseope eontrols
as
follows:
SWEEP RANGE
switeh
to any
position
exeept EXT.
SWEEP
VARI/EXT GAIN
eontrol
fullY
eloekwise.
V ATT switeh
to GND.
i
POS
to eenter
the
traee
vertieally.
2. A traee
should
be displayed
on the CRT.
3.
Adjust+POS
eontrol
so
the
beginning of
the traee
is visible, and aligned
with one
of the
gratieule
markers
near
the left
edge of the CRT
sereen.
4.
Adjust
HOR GAIN
trimmer
VR104 for a
traee length of
10
divisions.
VR102
is
aeeessible
through
a
hole in the bottom
of the
ehassis
(see
Fig.
1). If
the ease
is
removed, VR102
is loeated
as shown
in
Fig. 6.
TRACE
ROTAIION ADJUSTUENT
The
earthts
magnetie
field and
other
mag-
netie
fields
may
eause
the
traee
to tilt
when
the
oseilloseope
is
moved
from
one
loeation
to
another. This adjustment
rotates
the
CRT
to
eomeet
for traee
tilt.
1.
Set
the operating
eontrols
as
follows:
SWEEP
RANGE
to anY
Position
exeePt
EXT.
V
ATT
switeh
to GND.
2.
With no signal
applied,
a
traee should
be
present
on the
CRT.
Adjust
the
POS
eontrol to
eenter
the
traee vertieally
on
the CRT.
The
traee
should
be
parallel
with the
horizontal
gratieule
line.
If
traee tilt
is noted,
make the
following
adjustm ent.
3.
Refer
to
Fig.
8.
Loosen
the
two serews
a
b
L4
Length
of
horizontal
def
lection
Larger
H.
GAIN
Smaller
H.
GAIN