Audio System Adjustments; Hi-Fi Audio System Adjustment; Af Switching Position Adjustment; Frequency Response Check - Sony SLV-ED15 Service Manual

2-4.

AUDIO SYSTEM ADJUSTMENTS

• Adjust both Lch and Rch.
[Connection]
Audio
generator
600 Ω
Attenuator
AUDIO LINE IN
Feed signal both
channelssimultaneously.
Fig. 7-2-4.
2-4-1.

Hi-Fi Audio System Adjustment

(SLV-ED85/ED88/ED89/ED95/EZ66/EZ77)
• Set switches and knobs to the following positions to make ad-
justment unless otherwise specified.
INPUT SELECT switch ................... LINE
AUDIO MONITOR .......................... STEREO
[Adjustment Sequence]

1. AF Switching Position Adjustment

2. Frequency Response Check

3. Overall Level Characteristic and Distortion Factor
Check
4. Overall S/N Check
1. AF Switching Position Adjustment
(MA-377 BOARD)
Purpose:
Adjust the interval between A CH and B CH of tape playback
output. Improve the interchangeability with other tapes and sets.
When it is out of order, noisy sound is increased and big noise is
heard.
Mode
Signal
Measurement point
Measuring Instrument
Specified Value
Adjusting Method:
1) Connect MA-377 board JS401 to the GND for about 1 second
to activate the RF switching position adjustment mode.
2) Press the PLAY button to activate the AF switching position
adjustment mode.
3) Check appear "A H" on FL display.
4) Using the channels + and – buttons, minimize a chipped por-
tion. At this time, confirm that a noisy sound is not heard.
5) Press the pause button.
Audio level meter or
distortion meter
47 kΩ
VCR
AUDIO LINE OUT
PB
Alignment tape SP mode
color bar
CH1: Pin 3 of CN202
CH2: Pin 1 of CN202
Oscilloscope
Fig. 7-2-5
CH1
RF SWP
OK
CH2
NG
2. Frequency Response Check
Purpose:
Confirm that the frequency characteristic is within the specifica-
tion.
Mode
Signal
Measurement point
Measurement equipment
Specified value
Note: Tape path adjustment must have been completed.
Confirmation Method:
1) Supply a signal of 400 Hz, –17.5 dBs to both L and R chan-
nels of Audio Line Input.
2) Connect the audio level meter to the Audio Line Output.
3) Adjust the attenuator so that the audio level meter will indi-
cate –17.5 dBs.
4) Make recording.
5) Set an audio line input signal to 20 Hz and make recording.
6) Set an audio line input signal to 20 kHz and make recording.
7) Playback a recorded portion, and measure output levels at 400
Hz and 20 Hz and 20 kHz.
8) Confirm that the 20 Hz and 20 kHz playback output level within
a range of the 400 Hz playback output level 0 ± 2 dB.
7-3
Fig. 7-2-5.
REC and PB (SP, LP mode)
400 Hz, –17.5 dBs
20 Hz, –17.5 dBs
20 kHz, –17.5 dBs
Audio output terminal
Audio level meter
0 ± 2 dB