Sony RMT-V197, Service Manual

Page: 50 / 52

2-4-6. Playback Level Check (MA-286 Board)
Mode Playback
Signal Alignment Alignment tape : SP mode color bar
portion
Measurement point Video LINE OUT terminal
Measuring instrument Oscilloscope
Specified value A=1.00 ± 0.02Vp-p
[Check Method]
1)
Check that the playback level satisfies the specified value.
Fig. 7-2-9.
2-4-7. VCO Frequency Adjustment (MA-286 Board)
Mode Playback
Signal Alignment tape : SP mode color bar
portion
Measurement point IC500 pin
@§
Measuring instrument Digital voltmeter
Adjustment element CT500
Specified value A=2.4 ± 2.5Vdc
[Check Method]
1)
Adjust CT500 until DC output level at IC 500 pin
@§
(F. C)
satifies the specification.
Fig. 7-2-10
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. 7-2-10.
• Adjust in the SP mode if there is no special indications.
• Perform the adjustment setting the switch on the following
positions.
• CHANNEL switch .................................................. LINE 1
[Adjustment Method]
1.
ACE head adjustment.....Refer to the VHS mechanical
adjustment manual .
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 ” (9-973-623-
11).
2-5-2. E-E Output Level Check
Mode E-E
Signal 400Hz, –7.5dBs : IC540 pin
5
(
2
)
Measurement point CJ540 L/R
Measuring instrument Audio level meter
Specified value –7.5 ± 2dBs
( ) : R-ch
[Check Method]
1)
Input signal of 400Hz and –7.5dBs to the CN540 pin
5
(
2
).
2) Check that the audio output level is –7.5 ± 3dBs.
2-5-3. Overall Output Level and Distortion Factor
Check
Mode Self-record playback
Signal 400Hz, –7.5dBs : IC540 pin
5
(
2
)
Measurement point IC540 pin
3
(
1
)
Measuring instrument Audio level meter and Distortion
meter
Specified value Playback Level: –6.3 ± 3dBs
Distortion: 4.0% or less
( ) : R-ch
[Check Method]
1)
Input signal of 400Hz and –7.5dBs to the audio input.
2) Record signal.
3) Playback the recorded portion.
4) Check that the output level is –6.3 ± 3dBs.
5) Check that the distortion factor is 4.0% or less.
2-5-4. Overall Noise Level Check
Mode Self-record playback
Signal No signal (Insert a shorting plug into
the Audio LINE IN terminal)
Measurement point IC540 pin
3
(
1
)
Measuring instrument Audio level meter (IHF-A weighing
filter is used)
Specified value – 45.5dBs or less
( ) : R-ch
[Check Method]
1)
Record.
2) Playback recorded portion.
3) Check that noise level is – 45.5dBs or less.
7-5
A
H
A
1H
0V
Audio level meter
or distortion meter
47k
Ω
VTR
600
Ω
Audio oscillator
Attenuator
(CN540)
Audio line OUTPUT L/R
(CN540)
Audio line INPUT L/R