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3.1 Adjusting VCXO (27MHz)
1) 2) 3) 4) 5) Connect the frequency counter to TP1621 located under the card assembly and read the VCXO frequency. On the remote control unit, access Mode C screen on service support program. Press [PAGE+/-] keys for adjusting at 27MHz ± 50Hz. This calibration performs without any reception. [Exit] key: changes value of one step on [PAGE+/-] keys
3.2 Adjusting AGC
1) Tune to an analog channel carrying EIA color bars @ +3 dBmV. 2) Connect the DC voltmeter to TP1045. 3) Adjust VR1066 for maximum reading on the DC voltmeter (approx. +4.0V), then reverse the adjustment to reduce the reading by 2.0V+0.1V/-0.2V 4) Change input level to +15 dBmV. 5) Press INFO to turn the OSD off. 6) Verify the TV picture quality remains the same.
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3.3 Adjusting VCO
1) 2) 3) 4)
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Tune to an analog channel carrying EIA color bars @ +3 dBmV. Connect the DC voltmeter to TP1042. Adjust L1045 for a reading of 4.4V +/- 0.3V on the DC voltmeter. Verify the TV picture quality remains the same.
3.4 Adjusting analog video input level
1) Tune to an analog channel carrying an EIA color bars video signal, 400Hz sine wave at ± 25 kHz audio deviation, and a +5 dBmV visual carrier level. 2) On the remote control unit, press INFO to turn the OSD off. 3) Connect the oscilloscope No.1 to Composite Video output by 75� termination through. 4) Adjust the video input level turning VR1601 by two steps for a reading on the oscilloscope No.1. First step is to turn VR1601 to maximize the output peak-to-peak level just before the wave is clipped. Read that value. Second step is to adjust VR1601 to lower 10 mVp-p than the maximum value measured above. Take care that the output level should be over 900 mVp-p at that time.
D
This adjustment should be performed after finishing �3.2 Adjusting AGC� and �3.3 Adjusting VCO� .
The above mentioned adjustment value must be obtained in a case where the sync level is 40 IRE and the luminance level is 100 IRE when the signal is envelope-detected by a standard detector and measured by a video signal analyzer. Adjust the degree of modulation on the modulator so that the luminance level of the signal source for adjustment becomes 100 IRE ± 0.2 IRE. In this case, the ideal sync level is 40 IRE.
