6-4
2-4-3.
Normal Audio System Adjustment
• Make adjustment in the SP mode unless otherwise specified. Use
a normal VHS cassette for an adjustment tape.
• Set AUDIO MONITOR to normal.
2-4-4.
ACE Head Adjustment
Refer to the VHS mechanical adjustment manual
(S
MECHANISM) (9-921-647-11).
2-4-5.
E-E Output Level Check
[Adjustment purpose]
Confirm that the output level adjust the reference input is within the
specification.
Mode
E-E
Signal
400 Hz, –6.3 dBs
Measurement point
CN500 Pin
3
Measuring instrument
Audio level meter
Specified value
–6.3 ± 2 dBs
[Check Method]
1)
Input signal of 400 Hz and –6.3 dBs to the J480.
2)
Check that the audio output level is –6.3 ± 2 dBs.
2-4-6.
Frequency Response Check
[Adjustment purpose]
Confirm that the frequency characteristic is within the specification.
Mode
REC and PB (SP mode)
Signal
400 Hz, –26.3 dBs
4 kHz, –26.3 dBs
Measurement point
CN500 Pin
3
Measuring instrument
Audio level meter
Specified value
–6 dB to +4 dB
Note:
Tape path adjustment must have been completed.
[Confirmation Method]
1)
Supply a signal of 400 Hz, –26.3 dBs to both L and R channels
of Audio Line Input.
2)
Connect the audio level meter to CN500 Pin
3
.
3)
Adjust the attenuator so that the audio level meter will indicate
–26.3 dBs.
4)
Make recording in the SP mode.
5)
Set an audio line input signal to 4 kHz and make recording.
6)
Playback a recorded portion, and measure output levels at 400
Hz and 4 kHz.
7)
Confirm that the 4 kHz playback output level within a range of
the 400 Hz playback output level –6 dB to +4 dB.
2-4-2.
Hi-Fi Switching Position Adjustment
(MA-339 Board)
[Adjustment Purpose]
To adjust the link of the A-ch and B-ch of the tape playback outputs.
To make the unit compatible with other tapes and units. If this
specification is not satisfied, the link will appear on the screen and
the screen will be disrupted, etc.
Mode
Playback
Signal
Alignment tape: SP color bar portion
Measurement point
CH1: Pin
1
of CN341 (HF ADJ)
CH2: Pin
2
of CN270 (RF SWP)
Measuring instrument
Oscilloscope
Adjusting element
Remote commander CH +/–
Specified value
B=minimize
[Adjustment Method]
1)
Check that “A H” is indicated on FL display.
2)
Adjust so that part B becomes minimized at CH +/–.
3)
Write data EEPROM by pressing PAUSE button.
4)
Check that “A H” indicator turns off.
Fig. 6-2-5
B
CH1
HFADJ
CH2
RF SWP