Download 25WG3

VCO ADJUSTMENT
(I2C BUS CONTROL)
AGC ADJUSTMENT
(I2C BUS CONTROL)
1
2
7
Figure 1
BIAS BOX : ABOUT 4.5V
OSCILLOSCOPE
P201
TV SET
2
1
9. Call "AGC" in SERVICE mode.
10. Increase or decrease "AGC" by using
Volume so that obtain the highest
Voltage.
11. Press Volume slowly in the opposite
direction until the voltage drops 0.1V ~
0.3V lower than the highest level.
12. Change the antenna input signal to 63
~ 67dBµV, and make sure there is no
noise.
13. Turn up the input signal to 90 ~ 95 dBµV
to be sure that there is no cross
modulation beat.
-
+
-
+
7. Receive E-12CH (PAL COLOR BAR) signal.
Signal strength : 57 ± 1 dB ( 75ohm open)
8. Connect the oscilloscope to P201
(Tuner’s AGC Terminal) as shown in
Figure 1.
1. Receive E-10CH (210.25MHz) "PAL
Signal Strength: 60 ~ 70 dB
COLOUR BAR" signal.
2. Call "AUTO VCO" in SERVICE mode. If
the Channel frequency displays on
screen is 210.20MHz, skip (3), (4) & (5)
steps.
3. Press FUNCTION button to call
"DIRECT FREQ IN".
4. Push "2", "1", "0", "2", "0".
5. Then Press FUNCTION again.
6. Press Volume UP to run "AUTO VCO".
Once finishing, "OK" message display
on screen.
NO ADJUSTMENT POINT ADJUSTMENT CONDITION/PROCEDURE WAVEFORM OR OTHERS
VCO, AND AGC ADJUSTMENT
SERVICE ADJUSTMENT
NOISE MUTE
CHECKING
SP SUB VOLUME
(I2C BUS CONTROL)
2
3
RF SUB VOLUME
(I2C BUS CONTROL)
1
10. Receive the 400Hz modulated signal.
11. Turn up the volume control to Maximum
and make sure the sound is heard from
the speakers. Then put the unit in the
no-signal state.
12. Be sure that the sound mute is effective.
13. Finally turn down the volume control to
minimum.
5. Receive "COLOUR BAR" signal.
*Note : Terminated 8 ohm
Audio signal: 400Hz, 100%modulation.
to get 7.75 ±
(50kHz dev.)
0.1Vrms.
6. Connect Dummy load* to P3304.
(L Channel)
7. Connect VTVM’s probe to the P3304.
(1 R, 2 GND, 3 GND, 4 L, 5 NIL, 6 NIL
7 NIL 8 NIL)
8. Call the "SP SUB VOL" in the SERVICE
mode.
9. Increase or decrease "SP SUB VOL" by
using Volume UP/DOWN key, so that
the VTVM should read the value*.
1. Receive "PAL COLOUR BAR" signal.
Audio signal: 400 Hz, 100% modulated
(50kHz dev.)
2. Connect the Oscilloscope to the Audio
Out (L or R) terminal. (Terminate with
10k ohm impendence).
3. Call the "RF SUB VOL" in SERVICE
mode.
4. Increase or decrease "RF SUB VOL" by
using Volume UP/DOWN key, so that
the 400Hz sine wave be 1.76Vp-p.
Tolerence: 1.76 Vp-p ± 0.10 Vp-p.
NO ADJUSTMENT POINT ADJUSTMENT CONDITION/PROCEDURE WAVEFORM OR OTHERS
SOUND ADJUSTMENT
25WG3