Sanyo M7790K - PLAYBACK SENSITIVITY ADJUSTMENT; OSCILLATION FREQUENCY ADJUSTMENT

ELECTRICAL ADJUSTMENTS (continuea)
2. Insert a 10kHz test tape (Example: TEAC MTT-114) into the
cassette compartment. While playing back the test tape, turn
the azimuth adjusting screw until the wave forms of the right
and left channels are superimposed and set to optimum at
maximum reading on the VTVM.
Adjustment
R/P Head
Adjusting Screw
3. After the adjustment, secure the adjusting screw with paint
or glue.
PLAYBACK SENSITIVITY ADJUSTMENT
LEFT CHANNEL
1. Connect a VTVM to the test point TP101 as illustrated and
insert a 400Hz test tape for Dolby Calibration Level
(Example: TEAC MTT-150) into the cassette compartment.
VTVM 580mV
Test Point TP101
2. Check that the VTVM reads 580mV for the output of the left
channel while playing back the test tape.
3. If necessary, adjust the output to the specified one by
turning the potentiometer (P102) while the test tape is
played back.
RIGHT CHANNEL
Connect the VTVM to the test point TP201. Then, adjust the
potentiometer (P202) for the right channel by following the
same procedure as in LEFT CHANNEL.
OSCILLATION FREQUENCY ADJUSTMENT
1. Connect a VTVM across the resistor R104 and a frequecy
counter to the output terminal of the VTVM as illustrated.
Frequency Counter
ii
2.
Insert
a
cassette
tape
into
the
cassette
compartment
and
set
the
OSC
Switch
to
the
position
2.
Then,
set
the
unit
in
the
recording
mode.
3.
Turn
the
core
of
the
oscillation
transformer
(T301)
with
an
alignment
tool
until
the
frequency
counter
reads
60kHz
[
+50Hz].
RECORD & PLAYBACK
FREQUENCY RESPONSE ADJUSTMENT
e Chromium Dioxide Tape
Set the Tape Select Switch to “CrO2” and insert a chromium
dioxide tape (Example: TDK AC-512) into the cassette
compartment. Then, make the adjustment by the following
procedures.
LEFT CHANNEL
1. Connect an audio signal generator and an attenuator to the
left channel LINE IN, and a VTVM to the left channel LINE
OUT as illustrated.