10
20U200, 20U250
51U200, 51U250
51U500, 51U550
10-1 10-2
NTSC CHROMA ADJUSTMENT
NO. Adjustment part Adjusting procedure and conditions Waveform and others
1 SUB-TINT (I
2
C
BUS
CONTROL)
1. Receive the "NTSC3.58 Colour Bar" signal
through AV in.
2. Connect the oscilloscope to TP853 (Pin (5) of
P882) BLUE-OUT.
» Range : 100mV/div. (AC)(Use Probe 10:1)
» Sweep time: 10 µsec/div.
3. Call the "SUB-TINT" mode in service mode.
Adjust the "SUB-TINT" bus data to obtain the
waveform shown as Fig. 9.
4. Clear the SERVICE mode.
PROTECTOR OPERATION CHECKING
NO. Adjustment part Adjusting procedure and conditions Waveform and others
1 BEAM
Protector
1. Receive "Monoscope Pattern" signal.
2. Set CONTRAST MAX.
3. Set BRIGHT MAX.
4. During the Collector & Emitter of Q883/5/7
short, make sure the protector ON and switch
to standby mode.
* Select one of Q883/5/7 to do each
short test.
2 H, V Protector 1. Receive "Monoscope Pattern" signal.
2. Connect output of Bias Box to D607 cathode
(R606 side).
3. Set voltage of Bias Box to 18V and make sure
the protector is not work.
4. Set voltage of Bias Box to 27V, and make sure
the protector is work.
A/V INPUT AND OUTPUT CHECKING
NO. Adjustment part Adjusting procedure and conditions Waveform and others
1 VIDEO AND
AUDIO OUT-
PUT Check
1. Receive the "PAL Colour Bar" signal (100%
White Color Bar, Sound 400 Hz 100% Mod.)
2. Terminate the Video output with a 75 ohm im-
pedance. Make sure the output is as specified
(1.0 Vp-p ±3 dB).
3. Terminate the Audio output with a 10k ohm im-
pedance. Make sure the output is as specified
(1.76 Vp-p ±3 dB).
2 VIDEO AND
AUDIO INPUT
Check
1. Using the TV/AV key on the remote controller,
make sure that the modes change in order of
TV, AV1, AV2 & TV again and the video & audio
output are according to the input terminal for
each mode.
3 Other
Protectors
1. Once finish rectified Electrolytic Capacitor short
testing in +B line, check all possible damaged
components on +B line.
(Use random selected set for inspection)
W
Y
Cy G Mg R
B
Fig. 9
SIF (NICAM/IGR) ADJUSTMENT (51R500/550 ONLY)
NO. Adjustment part Adjusting procedure and conditions Waveform and others
1 VCO COIL
T2300
1. Receive "PAL Colour Bar" signal.
(Set AFT OFF, 203.25 MHz frequency)
2. Connect DC Voltmeter to Pin (1) of P2301
(Main Unit). (TP2300 in NICAM/IGR Unit)
3. Check and turn T2300 counter-clockwise (Left)
to 0V and then turn it clockwise (Right) until
TP2300 become 5V.After that, turn T2300
counter-clockwise (Left) until TP2300 become
2.5 ± 0.1 Vdc.
* UNIT BOARD ADJUSTMENT
Vcc 5.0 ± 0.1 Vdc
IF Input Frequency 38.9 MHz ± 10 KHz
Adjust T2300 until TP2300 (NICAM/IGR Unit)
become 2.5 ± 0.1 Vdc.
Check after assembly NICAM Board
Test Point: Pin (1) of P2301 (Main Unit)
Preset selected reception frequency (AFT
OFF)
Check Voltage 2.5 ± 1.0 Vdc.
Precaution: The Vcc, f0 and other factors are
considered in the unit board of the
1.0 V tolerance which differ from the
adjustment accuracy.
3 SUBWOOFER
OUTPUT
Check
1. Receive "PAL Colour Bar" signal ( Sound
400Hz, 100% Mod.)
2. Set the sound output to 2 Vrms by volume key.
(Speaker Impedance: 8 Ohm, Sound Output:
500mW)
3. Terminate the "Sub - Woofer" output with a 22
kΩ impedance.Make sure that the output is
5.6Vp-p ± 3dB.
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