Sony SLV-M20HF - Video Cassette Recorder, Service Manual

Page: 67 / 143

6-5
2-5. AUDIO SYSTEM ADJUSTMENT
• For the adjustment of the audio system, perform in the SP mode
if there is no special notes. Use the alignment tape.
[Connecting Instruments]
Fig. 6-2-11.
• Adjust in the SP mode if there is no special indications.
• Perform the adjustment setting the switch on the following
positions.
• INPUT SELECT switch ............................................ LINE 1
[Adjustment Method]
1.
ACE head adjustment.....Refer to the VHS mechanical
adjustment manual (S MECHANISM)(9-921-647-11).
2. E-E output level check
3. Overall Output level and distortion factor check
4. Overall noise level check.
2-5-1. ACE Head Adjustment
Refer to the VHS mechanical adjustment manual (S
MECHANISM)(9-921-647-11).
2-5-2. E-E Output Level Check
Mode E-E
Signal 400Hz, –7.5dBs : CJ570
Measurement point CJ570
Measuring instrument Audio level meter
Specified value –7.5 ± 2dBs
[Check Method]
1)
Input signal of 400Hz and –7.5dBs to the CJ461 L/R.
2) Check that the audio output level is –7.5 ± 3dBs.
2-4-4. Recording Chroma Level Check
(MA-335 Board)
Mode Recording (SP)
Signal Color bar
Measurement point IC201 pin
!¢
Measuring instrument Oscilloscope
Specified value A=450 ± 70mVp-p
[Check Method]
1)
Confirm the amplitude of recording chroma level becomes the
specified value.
Fig. 6-2-9.
2-4-5. Playback Level Check (MA-335 Board)
Mode Playback
Signal Alignment Alignment tape : SP mode color bar
portion
Measurement point Video LINE OUT terminal
Measuring instrument Oscilloscope
Specified value A=1.0 ± 0.1Vp-p (75
Ω
terminated)
[Check Method]
1)
Check that the playback level satisfies the specified value.
Fig. 6-2-10.
A
White (100%)
H
A
VTR
Audio line OUTPUT L/R
Audio line INPUT L/R
Audio
oscillator
Attenuator
600
Ω
Audio level
meter
or
distortion
meter
47 k
Ω