JVC AX-UXG6, Service Manual

Page: 58 / 108

2-42
UX-G6/FS-G6
Adjustment of
recording and
playing
sensitivity
Confirmation
of recording
and playing
distortion rate
Confirmation
of recording
and playing
S/N ratio
Confirmation
of erasing rate
Confirmation
of music
scanning
action
Confirmation
of NR effect
L:VR614
R:VR624
1. While applying 1kHz -28.8dB
to the line input terminal,
confirm that the sensitivity
level at the test point
TP_____ is 0dBs.
2. While recording and playing back
the above, adjust the recording
signal current with VR614 (Lch)
and VR624 (Rch) so that the
sensitivity level becomes-25.5dBs.
1. Record the test tapes ______
at 1kHz and reference input.
2. Check the output with a distortion
meter while playing back the
above test tapes, and confirm that
the respective distortion rates
comply with the standard value.
1. Halfway during recording at 1kHz
and reference input, sample the
input and perform non-signal
recording.
2. While playing back the above,
measure the difference between
the reference recording output
and non-signal recording output
with an electronic voltmeter, and
confirm that the measurement
complies with the standard value.
1. Apply 400Hz signal (Ref. + 10dB)
from the [LINE IN] terminal.
2. After rewinding the above, erase
a part of the recorded portion.
3. Measure the ratio of the erased
portion to the recorded portion
with an electronic voltmeter.
1. After loading the test tape
TMT6447, press the [PLAY] and
[FF] buttons or [REW] button.
After rewinding the tape, perform
music scanning and execute the
[PLAY] action.
2. After loading the test tape
TMT6447, press the [PLAY] and
[FF] buttons or [REW] button. In
this case, be sure not to perform
music scanning at the beginning
of tape winding.
While short-circuiting the
[LINE IN] terminal input,
1. Confirm the difference of noise
level at self-recording and playing
when the Dolby is off and Dolby
B is on.
*7
8
9
10
11
12
Normam tape:
-25.5dBs
0.5dB
Chrome tame:
-25.5dBs
2dB
Normal tape:
3.0% or less
Chrome tape:
3.0% or less
Normal tape:
38dB or over
Chrome tape:
40dB or over
55dB or over
8.5dB or over
The left and right level
difference of both normal
and chrome tape should be
within 0.5dB.
The sensitivity level should
be adjusted with normal
tape.
NR:OFF
Tape:Normal tape
Confirm the distortion rate
after adjusting the bias
current and recording level.
In this case, use the CCIR
ARM filter.
For measuring the erasing ratio,
connect a band pass filter(B.P.F)
between the electronic voltmeter
on the deck.
1kHz0VU
+20dB
input Deck
recording/
erasing
Electronic
voltmeter
Band pass
filter(B.P.F)
Items Adjusting position
Reference value
Remarks
Adjusting
position