Board Adjustment - Sony Trinitron KV-25XBR Service Manual

4-2. X BOARD ADJUSTMENTS
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SIGNAL SET UP
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V MAIN (L+RJ signal: 300 Hz, 247 mVrms (0.7 Vp-p}
V SUB (L-RJ signal: 400 Hz, 100% modulation
Carrier: 31.468 kHz
1.4 Vp-p
V SAP signal: 400 Hz, 100% modulation
(± 10 kHz deviation}
0.42 Vp-p
Carrier: 78.671 kHz
STEREO PILOT signal: 15. 734 kHz
0.14 Vp-p
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NOISE REDUCTION VARIABLE DE-EMPHASIS
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1.
2.
3.
4.
Sets RV1109 (VD ADJ) and RV1110 (SEPARATION}
to mechanical center.
Connect the 1 kn Resistor between the EMITTER and
9V LINE to turn OFF the Q1110.
Input 300 Hz, 46.9 mVrms (-24.3 dBs} sine wave
signal to dBX IN.
Read the output level (Va} of dBX OUT and make sure
that the level (Va} is -35 dBs
<
Va
<
-23 dBs.
Input 8 kHz, 106.2 m Vrms (-17.2 dBs} sine wave
signal to dBX IN.
Adjust RV1109 (VD ADJ} so that the output level (Vb}
of dBX OUT will become Vb (dBs}
=
[Va (dBs} - 11.3
(dB}] at this time.
0 dBs
=
0. 775 Vrms
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NOISE REDUCTION (TIME CONSTANT}
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1. Adjust RV1108 to 15
±
1 mVdc at IC1105 pin
@
as shown.
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(L -RJ GAIN
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• ,.
Receives a co,r,posite signal (SUB signal and
STEREO PILOT signal} from a MTS ENCODER to pin
0
of X-1 connector.
2. Set the MTS ENCODER switch as shown;
Noise reduction . . . OFF
SUB ............ ON
STEREO PILOT . . . ON
SAP. . . . . . . . . . . . . ON or OFF
3. Set the MAIN mode of the DECODER.
4. Adjust RV1106 to 332
±
10 mVrms on emitter of
01110.
Signal Setup
TV-multiplex1-------
oscillator
400 Hz
L-CH
IN
MTS
Encoder
R-CH
IN
- 23 -
KV-25XBR
KV-25XBR
RM-724/APM-X3U RM-724/APM-X3U
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SEPARATION
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1. Set to the SAP mode.
2. Input 300 Hz, 63.0 mVrms (-21.8 dBs} sine wave
signal to dBX IN.
Adjust RV1110 to 0.15 Vp-p
±
5 mV at IC1106
output pins @and@ fl] outputs, and to@ and
@
[Rf outputs, at this time.
level meter
oscillator
oscilloscope
o
8 kHz, 106.2 mVrms (-17.2 dBs} 10µ.F/16V
+
10µ.F
16V
9V
10kn
digital
multimeter
Em:___-
RMS meter
oscillator
300Hz
63.0mVrms
(-21.8 dBs}
-24-
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(L+RJ GAIN
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1. Supply a V MAIN signal to pin
0
of X-1 connector.
2. Sets the MAIN mode, and STEREO or MONO mode.
3. Adjust RV1104 to 0.6 Vp-p
±
20 mV at pins@ and
@
[Rf outputs and to pin
@
and
0
[L] outputs of
IC1106.