7-4
2-4-2. Recording Chroma Level Check
(MA-315 Board)
Purpose:
Check the chroma signal level after passing through the Y/C sepa-
rating circuit.
If shifted, the image is roughened and another color may appear
on the edges.
Mode E-E
Signal Color bar
Measurement point Pin !¢ of IC201
Measurement equipment Oscilloscope
Specified value 500 ± 80 mVp-p
Confirmation Method:
1) Confirm that the record chroma level is 500 ± 80 mVp-p.
Fig. 7-2-5.
2-4-3. Sync. AGC Check
(MA-315 Board)
Purpose:
Confirm that the video level is correct.
Mode E-E
Signal Color bar
Measurement point Pin #• IC201
Measurement equipment Oscilloscope
Specified value 2.10 ± 0.14 Vp-p
Note: Video output terminal must be terminated at 75 Ω.
Confirmation Method:
1) Confirm that the sync. AGC level is 2.10 ± 0.14 Vp-p.
Fig. 7-2-6.
2-4-4. X’tal Oscillation Frequency Check
(MA-315)
Purpose:
Confirm that the fsc is correct.
Mode PB
Signal Alignment tape SP color bar
Measurement point Pin %ª of IC201
Measurement equipment Frequency counter, Oscillo-
scope
Specified value 4,433,619 ± 96 Hz
Note: Connect the frequency counter through a probe of high input im-
pedance (about 10 MΩ) and low capacity (10 pF or less).
Confirmation Method:
1) Confirm that the frequency is 4,433,619 ± 96 Hz
2) Confirm that the amplitude is 500 ± 200 mVp-p.
Fig. 7-2-7.
500 ± 200
4
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