Service manual

3.4.2 Horizontal Oscillation /Deflection Circuit Failure
(Check “3.1 No Raster Generated” and “3.2.3.1 Horizontal Sync Unstable” before this item)
Check the voltage at Pin 1 of CN9A0 on the MAIN PWB.
Check the 215V line.
OK
NG
Check horizontal drive pulse.
Measure the drive pulse voltage at the gate of Q504 on the MAIN
PWB
,
and confirm that there is a rectan
g
ular out
p
ut of 10V
p
-
p
.
OK
NG
Check the drive pulse.
Measure the drain voltage at Q504 on the MAIN PWB, and
confirm that there is a rectangular output of 40 Vp-p.
NG
OK
Expected failure point
Q504, D501 on MAIN PWB or peripheral circuit
Check the waveform at the
base of Q550.
Measure the voltage waveform at the base of Q550 on
the MAIN PWB, and confirm that there is a rectangula
r
output of about 10Vp-p.
NG
OK
Expected failure point
Q550, T501, D502, D550 on the MAIN PWB or peripheral circuits
Check the drain waveform at Q5F1.
Check the drain voltage waveform of Q5F1 on the MAIN PWB,
and confirm that there is a waveform out
p
ut as shown below.
NG
Expected failure point
Q5F0, Q5F1, IC5C0 on the MAIN PWB or peripheral circuits
Approx.
215V
Horizontal duration
Horizontal period
Check the range of horizontal oscillation.
Confirm that the voltage waveform of Pin 11 of CN601 on the MAIN
PWB is a
pp
rox. 1V
p
-
p
.
OK
NG
Expected failure point
IC601 on the DEFL-SUB PWB or peripheral circuits
Expected failure point
Q501, Q502, Q503 on the MAIN PWB or peripheral circuits
OK
NG
Expected failure point
Q5F0, Q5F1, IC5C0 on the MAIN PWB or peripheral circuits
Expected failure point
Switching power circuit (See Item3.4.1)
Check the 215V line again after jumper in Pin 1 of CN9A0 line has been removed.
*Notice:
When reconnecting CN9A0, confirm that Pin 1 has discharged electricity.
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