Line Input Level - JVC TD-W717TN Service Manual

TD
-
W 717 TNC
/ J
TD
-
W 718 BKA
/ B / E / EN
/
G / U / UT
Adjustment and Confirmation Standard Adjusting
Conditions Item
LINE IN
: -
20 dBs
±
2 d B
MIC
: - 66 dBs
±
3 dB
1
.
Supply
a 1 kHz signal
to
the LINE IN terminals
at
-
20 dBs
,
confirm that LINE OUT level is
-
8 dBs
.
2
.
Supply a 1 kHz signal to the MIC input termi
-
nals
at
"
66 dBs
,
confirm that LINE OUT level
is
-
8 dB
$
.
3
.
Confirm that difference
level between left and
right within 2 dB at
LINE IN terminals and within
3 dB at MIC terminals
.
6 Input
sensitivity
level
check
* 7 REC/ PB
frequency
response
check
LINE INPUT LEVEL :
Ref
.
-
20
dB (
- 40 dBs
±
2 dB )
MIC
INPUT level :
Ref
.
-
20 dB (
-
86 dBs
±
3 dB )
NR SWITCH :
OFF
This step must be performed after the slave
oscillation adjustment
.
Record the 1 kHz and 12.5 kHz signals at the
level of
-
20 dB ( 20 dB lower than the reference
level )
.
Playing back the recorded signals
,
check that the
level of the 12.5 kHz signal is
0
±
2 dB to the
level of the 1 kHz signal
.
12.5
kHz level :
0
±
2 dB
higher . than
the
1
kHz level
.
Increase In high
frequencies
CQ
Low bias
current
Q )
C/
>
C
o
Appropriate bias
current
High bias
current
Frequencies
a
.
Decrease
in
high frequencies ' '
-
ta
O )
DC
0 50 Hz
1 k H z 12.5
kHz
1
.
Supply a 400 Hz signal to the LINE IN termi
-
nals record a 400 Hz signal at reference level
of
-
20 dB
.
2
.
Confirm that REC indicator should turn on
when LINE OUT level is
-
28 dBs during re
-
cording
.
Normal
,
Chrome
,
Metal :
"
28
dBs
±
1
dB
8 Recording /
playback
sensitivity
check
LINE OUT :
more
than 5 dBs
PHONES
OUT : more
than - 16 dBs
Suply 1 kHz signal to
the LINE IN terminal in the
Rec
.
monitoring mode
, and read non
-
clipped
signal level at the LINE IN terminal
.
9 Maximum
out put
check
\
Nornal :
Less than 2 %
Cr 02 / Metal
:
Less than 3 %
10 Checking
record /
playback
distortion
1 ) Record
a
1 kHz
, -
20 dBs signal to LINE IN
terminals
.
2
) Play back the recorded
part
,
Check the
output
with a distortion
meter to
see if the
value conforms
to
the standard value
.
1 )
Record at 1 kHz
, -
20 dBs signal
,
Stop the in
-
put by disconnecting from the terminal to
perform non
-
signal recording
.
2 ) Play back the recorded part
.
Measure the - 8
dBs recording output and the non
-
signal
recording output for comparison using an
electronic voltmeter
.
Check
to
see if the value
conforms
to
the standard value
.
11 Checking
signal to
noise ratio
recording
playback
Normal
,
More than 40
dB
Metal ,
chrome
;
More than 41
dB
( No
.
4358
) 21