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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
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