Panasonic CT20DC50B - 20" CLR TV/DVD COMBO, Руководство по обслуживанию

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Video: 100 IRE flat field, 30% modulation.
Audio: 300Hz, 100% modulation, stereo (left only)
(70 ± 5dB, 75
:
OPEN, P/S 10dB).
3. Adjust the MTS Low-Level Separation Adjustment
(M2) until the amplitude displayed on the scope is
minimum.
4. Apply the following signal from the RF signal
generator:
Video: 100 IRE flat field, 30% modulation.
Audio: 3KHz, 100% modulation, stereo (left only)
(70 ± 5dB, 75
:
OPEN, P/S 10dB).
5. Adjust the MTS High-Level Separation Adjustment
(M1) until the amplitude displayed on the scope is
minimum.
6. Repeat above steps 2 through 5 until the amplitude
is at minimum for both signals.
Clock Adjustment (Sb)
Preparation:
Connect the frequency counter from TPS1 (IC001
Pin 13) to cold ground ( ).
Note: Frequency Counter probe capacitance should
be 8pF or less.
Procedure:
1.
Turn the Receiver “OFF” with the AC power
applied.
2. Measure TPS1 (IC001 pin 13) for the frequency of
the waveform and record the reading.
Note: Pin 13 measurement must have at least four
digits of resolution following the decimal point.
Example: 000.0000
3. Turn the Receiver back “ON”.
4. Place the Receiver into Service Mode for making
electronic adjustment, select the Clock Adjustment
DAC (Sb).
5. Calculate and set Sb based on the following
formula:
Note: Pin 13 measurement will not change
regardless of the value stored in Sb.
Vertical Size (B7)
Adjust the VERTICAL SIZE DAC control, B7, until the
top and the bottom edges of the raster are visible and
touch the bezel edge. Best results can de obtained with
a round test pattern. Linearity adjustment is done
automatically when the size is being adjusted.
Service Adjustments (Mechanical Controls)
VCO Field Alignment L105
(IC101 pins 35 & 36)
1. Turn Receiver “ON” and let it warm up for a
minimum of 20 minutes prior to continuing with the
adjustments.
2. Connect a balance antenna and select a midband
channel (Ch 10, 11 or 12).
3. Attenuate the signal strength for a weak noisy
video.
4. While observing the picture tube, adjust L105 until
best picture appears.
5. Change channels and observe that they are tuning
properly.
6. If the channel monitored is not clear, repeat steps
1, 3 and 4 while applying a stronger signal.
Focus (part of T551)
Preparation:
Connect a Signal generator and select a dot pattern.
Procedure:
Adjust the FOCUS control to obtain the sharpest and
clearest dot pattern.
a. Adjust for best center.
b. Adjust for best area between the center and
top right corner.
Sb 128 0.901
6
u10
244.1406 pin13 Hz
> @
–
^ `
244.1406
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