Stereo Vco Adjustment; Filteradjustment; Separationadjustment - Hitachi 36UX52B\CZ77 Service Manual

M7LXU
Sound modulation condition
Noise reduction encoder: ON
Stereo signal
1 .R=O (L only), 300Hz, 30% modulation
(see note)
Z.R=O (L only), 3kHz, 30% modulation
(see note)
Monaural signal
3. Monaural, 400Hz, 100% modulation
(PRE-EN Off)
SAP signal
4.SAP, 300Hz, 30% modulation (see note)
(2) Connect AC vottmeter Vo to IS01 pin @.
Use the AC voltmeter of Matsushita made, model
VP-950C or equivalent.
(3) Apply +9V to 1201, IS01 (Refer to item 4-2-l(1))
(4) Same as item 4-l (1)
(5) Select adjustment code "A04"
Adjustment Procedure
(I) Select sound input @ and adjust the data "A04"
to Vo=sig 450mVrms + 1 OmVrms at IS01 pin @ .
4-5 Stereo VCO adjustment
Adjustment PreQaration
(1) Same as items 4-2-l(1) and 4-l(1).
(2) Connect a frequency counter to IS01 pin @
Use the prove of 1 :I.
(Prove standard Ri 2 1 MQ, Ci I 15pF)
(3) No signal input of pin a (ISOI).
(4) Select adjustment code "A01 .'I
(5) Connect capacitor (10Of~F/16V) as follows.
Adjustment Procedure
+ -
F4
CS06
1 OO/AF/I 6V
(I) Adjust the data "A01 " to set 15.73&O. 1 KHz by
" 4 b " keys,
(2) Delete capacitor ( 1 OOuF/16v)
4-6 Filter Adjustment
Adjustment PreDaration
(1)
(2)
Set capacitor lOOpF/16V as shown as follows.
Apply the signal to IS01 pin @ with the circuit
shown as follows.
F/E
- 1 RS21
UlOl@ : r, I
+ -
I +m
VW f
l=i 0 IS01
UP61A
(For CZ73)
j sftf j RS26
CS06
---I
10Oj.~F/f 6V
@I SG output signal spec.
0 Frequency
f=1573kHz (Sin wave)
0 Signal Level
V=l OOmVrms
(3) Connect an AC voltmeter or oscilloscope to IS01
pin @.
(4) Select adjustment code "A03."
Adiustment Procedure
(1) Adjust the data "A03" so that the voltage of IS01
@ pin is minimum by " 4 b " keys.
4-7 Separation Adjustment
(The adjustment of items 4-4-l and 4-6 must be com-
pleted first)
Adjustment Preparation
(1) Use the same circuit as input level adjustment
(4-4-l).
(2) Connect an AC voltmeter to AUDIO AMP to IS01
pin @J or connect an oscilloscope.
(3) Select adjustment code "A06" and set data
"D032."
Adjustment Procedure
(1) Select sound input signal @and select adjust-
ment code "A05." Adjust by 'I 4 ) " keys so that
300Hz level is minimum (L separation adjustment)
(2) Select sound input signal 0 and select adjust-
ment code "AO6." Adjust by " 4 ) " keys so that
3KHz level is minimum (H separation adjustment).
(3) Repeat (1) and (2).
Adjustment precision:
within +IdB from minimum point.
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