— 11 —
SERVICE ADJUSTMENTS (Continued)
SUB COLOR AND SUB HUE ADJUSTMENT
Sub Color
1. Connect a color-bar generator to the analog antenna
terminal. Set picture controls to Auto level.
2. Switch the generator to the color-bar (NTSC) pattern.
3. Connect oscilloscope probe to TP35 and ground.
4. Turn off the receiver and disconnect the AC power cord.
5. While pressing the VOLUME – key, reconnect the AC
power cord. The Service Menu display will now appear.
6. Select NO. 3C (SCO: Sub Color, Bit 5 ~ 0) with
or
key.
7. Set the data with numeric keys 5 ~ 0 for 1.15 ± .15 V p-p.
See Figure 7.
Sub Hue (Tint)
8. Select NO. 3D (STI: Sub Tint, Bit 5 ~ 0) with
or
key.
9. Set the data with numeric keys 5 ~0 for waveform
shown in Figure 7 (Stair Steps).
HIGH VOLTAGE HOLD-DOWN TEST
Every time the receiver is serviced, the HIGH VOLTAGE
HOLD-DOWN circuit must be tested for proper operation by
following these steps:
1. Connect receiver to 120V AC line. Tune receiver to active
channel. Reset the picture controls to the Auto level.
2. Check that the voltage measured between TP7 and TE7
(ground side) on the P/D PC board is within 16.5 VDC to
21 VDC. If the voltage is out of this range, the Hold-Down
Circuit must be checked.
3. Connect a DC Voltage supply to TP7 and TE7 through a
100 ohm 1/4W resistor. Adjust the DC voltage to 23 VDC.
The receiver should shut down, losing raster and sound.
Then the receiver should turn off automatically.
This reaction indicates that the Hold-Down circuit is func-
tioning properly. If the receiver does not shutdown, a
malfunction is indicated and its cause
must
be found and
corrected.
4. To obtain picture again, remove the DC Supply and wait
a few minutes. Now turn on the receiver.
MULTI-SOUND SECTION ADJUSTMENTS
Note: Multi-Sound Section must be adjusted after
A101 (U/V Tuner), IC3401 (MTS Decoder), Digital
Module or IC802 (EEPROM) is replaced.
INPUT LEVEL ADJUSTMENT
1. Connect a signal to the analog antenna terminal with
audio of 1 KH
Z
100% modulation.
2. Turn off the receiver and disconnect the AC power cord
(AC 120V line).
3. Connect voltmeter (RMS) to TP317 and ground on the
Main PC board.
4. While pressing the VOLUME – key, reconnect the AC
power cord. The Service Menu will now appear.
5. Select NO. 80 (ATT: MTS Input Level) with the
or
key.
6. Adjust the + or – key for a voltmeter reading of 400 ±
20 mVrms at TP317.
SEPARATION ADJUSTMENT
7. Turn off the receiver and disconnect the AC power cord
(AC 120V line).
8. Connect oscilloscope CH1 to TP317 and CH2 to TP318
and ground.
9. Connect an MTS TV/Stereo generator to antenna terminal.
10. While pressing the VOLUME – key, reconnect the AC
power cord. The Service Menu will now appear.
11. Select pilot, 300Hz audio frequency and Left modulat-
ing signal.
12. Select NO. 81 (WDB: Wide Band) with the
or
key.
13. Adjust the + or – key for minimum low frequencies at
TP317. (See Figure 8.)
14. Select 4 KHz audio frequency and Right modulating signal.
15. Select NO. 82 (SPC: Spectral) with the
or
key.
16. Adjust the + or – key for minimum high frequencies at
TP318. (See Figure 8.)
Repeat adjustments (steps 11–16) until no further decreases
in amplitude can be obtained. Press the MENU key to turn
off the Service Menu display.
Minimize L leakage
Minimize R leakage
4KHz
300Hz
TP317 (R)
TP318 (L)
Figure 8. Separation Adjustments
W
B
C
M
G
1 H
R
Y
Figure 7. Sub Color
1.15 ± .15 V p-p
