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4.1.3 Audio circuit
Note:
• GND (Ground) should be taken from the Tuner shield
case.
4.1.3.1
Audio REC FM
Signal
(A1)
• Ext. input
(A2)
• Audio: No signal
(A3)
• Video: Color (colour) bar signal [NTSC]
Mode
(B)
• S-VHS EP
• TBC:OFF
Equipment
(C)
• Oscilloscope
Measuring point (D)
• TP2253 (A. PB FM) [Main board]
External trigger (E)
• TP111 (D.FF)
Adjustment part (F)
• VR2251 (FMA REC LEVEL)
Specified value (G1)
• 350 ± 50 mVp-p
(G2)
• More than 200 mVp-p
(1) Apply the external trigger signal to D.FF (E) to observe the
Audio PB FM waveform at the measuring point (D).
Please refer to "DR-MV1SUS No.YD006" about this section.
(2) Record the signal (A3) with no audio signal input in the
mode (B), and play back the recorded signal.
(3) Set the VCR to the manual tracking mode.
(4) If the A.PB FM level is not within the specified value (G1),
perform the adjustment in a following procedure.
(5) Adjust the Adjustment part (F) so that the A. PB FM level of
the higher channel level becomes the specified value (G1).
(Adjust before recording, then confirm it by playing back.)
(6) If the specified value (G1) is not obtained, adjust the Ad-
justment part (F) so that the waveform level of the lower
channel level becomes the specified value (G2). (Adjust
before recording, then confirm it by playing back.)
Specified
value (G2)
SECTION 5
TROUBLESHOOTING
V. rate
Fig.4-1c Audio REC FM
Specified
value (G1)
(No.YD012)1-5
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