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AUDIO NORMAL
CIRCUIT
Note:
.
Set the following
remote control button to the positions
indicated below, before making following adjustments.
REMOTE CONTROL BUITON
POSITION
TAPE SPEED
SP
INPUT
AV
AUDIO
L
2-3-3. BIAS LEVEL ADJ.
Measuring Point
Measuring Equipment
Adj. Condition
TP232 (HOT)
Oscilloscope
REC (SP) mode
TP231
(COLD)
AC voltmeter
Blank tape
Frequency counter
Adj. Location
Adj.
Value
VR231 (BIAS)
26 mVrms
1.
Load the VCR with a blank tape and select the REC (SP)
mode without all incoming signal.
2.
After confirming on the oscilloscope that a 70 kHz + 5 kHz
sine wave is being output, adjust VR231 (BIAS) so that the
AC voltmeter's
reading is 26 mVrms.
AUDIO FM (Hi-Fi) CIRCUIT
Note:
.
Set the following
remote control button to the positions
indicated below, before making following adjustments.
REMOTE CONTROL BLJITON
POSITION
TAPE SPEED
SP
INPUT
AV
AUDIO
Lor R
2-3-4.
A-FM
CARRIER
FREQUENCY
ADJ.
Measuring Point Measuring Equipment
Adj. Condition
TP233
Frequency counter
REC (SP) mode
Blank tape
Adj. Location
Adj. Value
VR233 (L-FO)
1.4
MHz
f
5
kHz
VR234 (R-FO)
1.8 Mfiz t
5 kHz
l--
1.
2.
3.
4.
5.
6.
Press the INPUT button on the remote control and select
"AV".
After recording/playing
back for 10 to 20 seconds with the
no-signal input, select Lch with the AUDIO button on the
remote
control,
and check the reading
of the counter
connected to TP233.
If the carrier frequency of Lch is higher than 1.4 MHz, rotate
VR233
(L-FO) slightly
to the right, towards
the board
component
side.
Next switch to Rch and check the reading of the counter. If
the carrier frequency of Rch is higher than 1.8 MHz, rotate
VR234
(R-FO) slightly
to the right, towards
the board
component side.
After recording/playing
back for 10 to 20 seconds with the
no-signal
input again. If the carrier frequency
of Rch is
higher than 1,8 MHz, rotate VR234 (R-FO) slightly to the
_
right.
If lower, rotate slightly to the left, Switch to Lch using the
AUDIO button. If the carrier frequency of Lch is higher than
1.4 MHz, rotate VR233 (L-FO) slightly to the right. If lower,
rotate slightly to the left.
Repeat recordinglplay back and checking of the frequencies
until the carrier frequency of Rch becomes 1.8 MHz f
5
kHz and that of Lch becomes 1.4 MHz * 5 kHz.
Note:
The carrier frequency
of the part recorded first is not
stable because it is written over. Therefore,
no signal
recording for 10 to 20 seconds must be performed.
-
–14–
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