Sony RMT-V231B, Service Manual

Page: 61 / 76

6-6
2-5-3. Overall Output Level and Distortion Factor
Check
Mode Self-record playback
Signal 400Hz, –7.5dBs : CJ570
Measurement point CJ570
Measuring instrument Audio level meter and Distortion
meter
Specified value Playback Level: –7.5 ± 3dBs
Distortion: 4.0% or less
[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 –7.5 ± 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 CJ570
Measuring instrument Audio level meter
Specified value – 45.5dBs or less
[Check Method]
1)
Record.
2) Playback recorded portion.
3) Check that noise level is – 45.5dBs or less.
2-6. TUNER SYSTEM ADJUSTMENT
2-6-1. Separation Adjustment (MA-327 Board)
Mode E-E
Signal RF signal
Video : Color bar
white (100%) modulation
Audio : L: 400Hz, R: 2kHz
30% modulation
Electrical field:
60-80dBm/75
Ω
terminated
Measuring instrument Audio level meter
Measuring point LINE OUT L
Adjusting element RV731
Specified value 2kHz component minimum
[Adjustment Method]
1)
Connect an audio level meter to LINE OUT L channel via HPF.
2) Feed the RF signal from RF IN terminal.
3) Adjust with RV731 so that the output level satisfies the specified
value.