Service manual
Table Of Contents
TROUBLESHOOTING
GUIDE
No
raster,
no
sound (B1 is
normal)
NOTE:
1702
locations in (
).
[Cause]
Horizontal
deflection
circuit
Problems in the horizontal deflection
circuit
hinder generation
of
high focusing voltage,
BH
160V
and
B2
12V,
resulting in no raster, no sound.
1.
As
long
as
normal
BH
160V
is generated,
the
horizontal
output
circuit
properly operates, pro-
ducing pulses during the flyback period
of
the saw-tooth wave current passing through the horizon-
tal
deflection
coil.
If
a problem is
found
with
normal
BH
voltage,
the
problem area should
be
the
secondary coil
of
the
flyback
transformer.
2. When the
AC
voltage
between
base and
emitter
of
the
horizontal
output
transistor
X01
(0522)
is
about
O.SV,
it
is supplied
with
input
pulses. The problem is therefore in
the
horizontal
output
circuit. When,
however,
X01
(0522)
is shorted,
this
AC
voltage
is
not
indicated even
if
there
are
input
pulses
at
X01
(0522).
3. AC voltage is measured
between
the collector and ground
of
X501
(0521)
horizontal drive
as
shown.
When
the
specified voltage is
shown
on
the
meter,
the
horizontal
output
circuit
is
the
problem;
while,
when
there is no voltage indication,
the
trouble
is in some element(s) preceding
X501
(0521).
Check
if
those transistors and
les
are damaged using a voltage measurement.
C
START
t
Vc.
VB
at
X701
(0501)
• ABNORMAL
I
X-Ray protector
Check X701
(0501)
+ NORMAL
Is normal
BH
160V
generated?
NORMAL
+
+
NO
IFailure in
T502,
L504
(T01, L523),
Check
Vc
at
X01
(0522)
ABNORMAL (Trouble in horizontal
or high voltage module
horizontal
output
transistor
output
circuit)
• Approx. NORMAL
,
Check
AC
voltage between base &
Check short or open
of
X01,
001,
C512, C513,
C514.
C515
(0522,
emitter
of
X01
(0522)
horizontal
0522,
C526,
C534,
C535)
output
transistor
More than AC
50
V
+OV
AC _
0.8V"'Trouble
in horizontal
output
circuit
II
Check breakage
of
T501
I
Check
AC
voltage between
Check T501 (T521) primary coil,
(T521)
collector
& ground
of
X501
r-
R512,C510,X501,
R503, R504,
(0521)
horizontal drive
R505, R508,
C508,
IC501
(0521,
IC501,
etc.)
17