Service manual
Table Of Contents
Only single horizontal line, normal sound
NOTE:
1701
- First check
if
FR401 is broken or not.
If
this
is broken,
the
trouble is due
to
short
of
X401 or break
of
0401
.
1702
- Circuits in
1702
monitor
differ
but
the
operation remains
the
same. Check
vertical
controls/deflection
circuits.
[Cause]
Malfunction
of
the vertical deflection circuit. When the vertical deflection
circuit
is
faulty,
saw-tooth
current is
not
applied
to
the
vertical deflection coil, resulting in a single horizontal line. Dur-
ing troubleshooting, reduce brightness
contrast
to
prevent
an
ion
spot
on
the
CRT.
1. R401 broken,
C403,
0402,
C413
short:
82
12V
is
not
supplied, disabling
IC501.
2. R411, R412 broken, C407 short: the voltage at IC501 pin 3 is set
to
zero disabling the V-amplifier
and the voltage at pin 2 is set
to
zero
to
turn
off
X402.
3. R414,
R415
are broken:
VB
of
X401 is zero disabling X401 and
X402.
4.
Also check
if
C402
is
short
or open.
5. Too high
VB
of
X402
is because
of
C401
short
or failure in IC501 or
X402.
Note: When the voltage generator fails
to
supply
82
12V
to
the secondary coil
of
the
flyback
transformer
of
the
horizontal
output
circuit due
to
malfunction,
a single horizontal line
and no sound
will
result.
( START
)
I
VB
at
the
vertical
output
;-
transistor
X402
is nearly
r---
zero
Vc.
VB.
VE
of
X401
and
Vc
of
X401
is very high
while
VB,
VE
of
X401
Vc
of
X402
are very high
and
Vc
of
X402
are
(more than
100
V)
very
low
R401, R411,
R412
or
R414,
R415
broken,
R413
broken.
C403,
X402
short,
0402,
C407,
0405
short
IC501
faulty
X402
open IC501
faulty
20