1.
Conneet
power
eord
to
Turn on POWER
switeh.
light should be lit.
live
ae outlet.
The
neon
pilot
TROT'BI,ESHOOTING
The following
nOperational
Cheeks" will eompletely eheek
funetional
operation of
oseilloseope.
They should be
performed
in
the listed sequenee.
If
the
seope
fails
any
step,
to
the
eorresponding
nTroubleshooting"
information
to
isolate
the defeetive eireuit.
Refer
t,
VOLTAGE
CHART
seetion
of
this
manual
for normal voltages at all transistors
and the
{
After repairs
are eompleted,
the
"Operational
Cheeksft
should be repeated to
verify tha'
repair has
fully
restored
proper
operation,
and to
make sure
that
no
additional
problem
exists
OPBBAIIONAL
CHECK
TB,OT'BI,ESHOOIING
No
pilot
light usually indieates a
blown
fuse
or
failure
in
the
power
input
eireuit.
Cheek fuse,
power
transformer, POWER switeh
S106,
neon
lamp Nl, R15?.
If unit
blows
fuses,
diseonneet
power
trans-
former seeondary windings
one at a time
and
eheek
for shorted
power
supply.
Espeeially
eheek
power
supply
filter eapaeitors C114,
c115,
C116, C117, C118,
C119, C120.
No
dot usually
indieates a
high voltage
power
supply
or
CRT
failure.
Cheek
voltages at CRT
pins.
If
high
voltage
abnormal,
eheek 500 V
winding
of
power
transform er,
D107, D108,
cl21-Cl26, R158-Rl67,
VRl03, VR104.
If
high
voltage
normal, eheek CRT
filam
ent
voltage. Cheek CRT
filament with ohmmeter
(power
removed).
Do
not
allow
a bri.ght dot
to
remain
stctroncry
f
or more
thon
a
few
seconds.
fi7e
CRT
may
become
permanently
burned.
Reduce
INfENSIfy
or
go
into
sweep mode.
Rotate
t
POSITION
eontrol
to
both
extrem
es.
-
Dot
should be adjustable
beyond
the
top
and bottom of sereen.
Adjust dot to vertieal
eenter of
sereen.
v
!t
Set
V
ATT
switeh to
GND and SWEEP
RANGE switeh
to
EXT. Set
I
POSITION
snd<>pOSITION
eontrols to mid-position
and
INTENSITY
eontrol to maximum.
A
dot
should appear in
the approxim ate
eenter
portion
of the
sereen.
Non-eentered
or laek of
indieates vertieal ehannel
voltages
at
Q101-Q111.
adjustment range
problem.
M
easure
20
v
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