Sony LBT-LX7 Service Manual page 16

3. Mode: Playback
test tape
P-4-A100 main board
CN301
(10kHz, –10dB)
Pin 3 (L-ch)
L
set
R
Pin 1 (R-ch)
Waveform of oscilloscope
in phase 45°
good
4. After the adjustments, apply suitable locking compound to the
parts adjusted.
Adjustment Location: Playback Head (Deck A)
Record/Playback/Erase Head (Deck B)
Remove the cassette lid.
Reverse Foward
oscilloscope
Pin 2 (GND)
90° 135° 180°
wrong
Tape Speed Adjustment (Deck A)
Note: Set the test mode using the following method and begin tape
speed adjustment.
In the test mode, the speed will switch to double speed or
normal speed each time the HI-SPEED DUB button is pressed.
Procedure:
With the power turned ON, press the c/CLOCK SET button,
ENTER button, and DISC 3 button simultaneously.
(The "VOLUME" on the fluorescent display tube will blink while
in the test mode.)
To exit the test mode, press the "/1 button.
1. Insert the WS-48B into deck B.
2. Press the H button of deck B.
3. Press the HI-SPEED DUB button and play the tape at double speed.
4. Adjust RV1001 of the LEAF SW board so that the reading of
the frequency counter becomes 6000 ± 180 Hz.
5. Press the HI-SPEED DUB button and play the tape at normal speed.
6. Adjust RV1002 of the LEAF SW board so that the reading of
the frequency counter becomes 3000 ± 90 Hz.
Adjustment Location: LEAF SW board
Sample Value of Wow and flutter
W.RMS (JIS) less than 0.3%
(test tape: WS-48B)
Playback Level Adjustment (Deck A, Deck B)
Procedure:
Mode: Playback
test tape
P-4-L300
(315Hz, 0dB)
set
Deck A is RV311 (L-CH) and RV411 (R-CH), deck B is RV301
(L-CH) and RV401 (R-CH)
so that adjustment within the following adjustment level.
Adjustment level:
CN301 playback level: 301.5 to 338.3 mV (–8.2 to –7.2 dB)
level difference between the channels: within ± 0.5 dB
Adjustment Location: AUDIO board
Adjustment Location
[LEAF SW BOARD]
RV1001(High Speed)
RV1002(Normal Speed)
RV1002 RV1001
level meter
main board
CN301
Pin 1 (R-ch)
Pin 3 (L-ch)
15