Hitachi MX-W50 - AM TUNER ADJUSTMENT

‘MX-W50
Note 1:
19), and adjust the waveform until it becomes maximum and symmetrical.
Note 2:
symmetrically, and the A-B line becomes liner.
Note 3:
Fig
Noise
. 19
AM TUNER ADJUSTMENT
FUNCTION: AM
MODULATION: 400Hz 30% Mod. 74dB u/m
Sequence
Covering
(Note 5)
Connection
Liner portion
Setting
Fig.
Apply low-input signals from a sweep generator (with a smail amount of noise superimposed on IF waveform as in Fig.
Cause and S curve to appear on the screen by T201 as shown in Fig. 20,and adjust it until points A and B are positioned
Connect a DC null meter TP. 4 and TP. 5 then make adjustment until it reads 0 + 20mv.
B
20
Adjust for
Tracking
Note 4:
Input
@® ©
TP. 7
o- WHE)
100k 0.14
Output
TP. 8
oMH EG)
100k 0.1p
Loop antenna
20Q
400Hz
30% Mod.
Tuning
(MW) 530kHz
(for US, CS)
522kHz
(except US, CS)
(LW)
153kHz
Signal
S)
450kHz
Adjust
B
(MW) L152
(LW) L154
Indication
© ©
(Note 5)
1.3V + 0.1V
(for US, CS)
1.2V + 0.1V
(except US, CS)
(Note 6)
1.2V + 0.1V
(Note 6)
Audio output
(MW)
603kHz or
600kHz
(MW)
603kHz or
600kHz
L154
(LW)
163kHz
(LW)
163kHz
and adjust so that portion A of the wareform shown in Fig. 22 is flat.
Note 5:
Note 6:.
Note 7:
Covering is factory preset. If it is touched erroneously, perform this procedure.
Connect the DC volt meter. to TP. 9, TP. 10 and adjust L 152, L 154.
At first, set the input level to 74 dB u/m. As the adjustment advances, reduce the input level to and allowable mi nimum
V max.
(Note 7)
Adjust
T202
so
that
the
wareform
shown
in
Fig.
21
is
obtained.
After
adjustment,
increase
the
sweep
generator
output
level (approx. 60 dB), and repeat the adjustment until the maximum output is obtained at the specified frequency.
| | i ; portion
Fig. 21
Fig. 22
~10—
Install a condenser of about 150 PF parallel to C425 in case
the recording beat at MW and LW is too large.