LG Goldstar CN-14D90 Adjustment Instruction

These instructions are applied to only NC-6HA chassis.
Notes
1.Because this is not a hot chassis, it is not necessary to use an
isolation transformer.
However, the use of isolation transformer will help protect test
instrument.
2.Adjustment must be done in the correct order.
3.Supply 100~240V A.C./50~60Hz.
4.The receiver must be operated for about 30 minutes proir to
the adjustment.
CONTENTS
1. VCO/AFT Adjustment
2. SIF Adjustment
3. Stereo separation Adjustment
4. AGC voltage Adjustment
5. Screen voltage Adjustment
6. White Balance Adjustment
7. FOCUS Adjustment
8. Sub-Bright Adjustment
1. VCO/AFT Adjustment
1) Connect the DMM to pin 13 of IC501.
2) Disconnect the antenna cable.
3) Press SET-UP buttons on the Remote control and the front
panel of TV set at the same time to get into the adjustment mode.
Press channel Up/Down buttons to select an adjustment.
Press volume Up/Down buttons to vary the data.
4) Select APCADJ mode by pressing channel Up/Down
button.
5) Adjust APCADJ data by pressing volume Up/Down button
untill the DMM reads 3.8+_ V.
6) Input the Digital pattern signal.
7) Select VCORUN mode by pressing channel Up/Down
button.
8) Adjust VCORUN data by pressing volume Up/Down button
untill the DMM reads 3.8+_0.2V.
2. SIF Adjustment
1) Input 100% modulated 1KHz sound signal.
2) Connect DMM to pin 7 of IC501.
3) Adjust L104 untill DMM reads 3.8+_0.2V.
3. Stereo separation Adjustment
3-1. Preparation
1) Connect the measuring equipment to the TV as show in Fig. 1.
2) Press SET-UP buttons on the Remote control and the front
panel of TV set at the same time to get into the adjustment mode.
3-2. ATT input level adjustment
Select ATT with CHANNEL button and adjust with VOLUME
button until the voltage of JP at R620 is 1.414+_0.03Vp-p.
ADJUSTMENT INSTRUCTION
0.3
0.2
3-3. Stereo VCO(ST) Adjustment
1) Disconnect the Modulator and connect C1 and the frequency
counter.
2) Select ST VCO with CHANNEL button and adjust with
VOLUME button until the frequency of JP at R617 is
15.734+_0.1KHz.
OSCILLOSCOPE
IC601
7
C607
TV SOUND MULTIPLEX
MODULATOR(USA)
3-4. Filter Adjustment
Select FILTER with CHANNEL button and adjust with
VOLUME button until the waveform becomes minimum.
3-5. Separation Adjustment
1) Select ST L-only 300Hz signal 30% Modulation of Modulator.
2) Select LSPRT with CHANNEL button and adjust with
VOLUME button until the waveform is minimum.
3) Change the frequency of Modulator to 3KHz.
4) Select HSPRT with CHANNEL button and adjust with
VOLUME button until the waveform is minimum.
5) Select LSPRT and reduce 10 steps.
3-6. SAP VCO Adjustment
1) Disconnect the Modulator and connect C1 and the frequency
counter.
2) Select SAP VCO and adjust until the frequency becomes
78.67+_0.5KHz
4. AGC voltage Adjustment
4-1. Preparation
Connect the DMM to J64 on Main PCB.
4-2. Adjustment
1) Select AGCDLY with CHANNEL button in Adjustment mode.
2) Adjust with VOLUME button until the voltage is 5.6+_0.1V.
5. Screen Voltage Adjustment
5-1. Make the screen has the horizontal line by Remote control.
5-2. Turn the screen control clockwise until the Horizontal line is
visible and turn it counterclockwise until the Horizontal line is
faintly visible.
- 1 -
JP
FREQUENCY COUNTER
R617
26
C619
<Figure 1>