JVC KD-A66 Service Manual

KD-A66A/B/C/E/J/U
{[V] Electrical circuit adjustment procedure
In th steps marked by an asterisk (*), adjustment should be
performed, however, only checking is sufficient with steps
other than those.
1* . Play back the VTT-664 Reference
tape (1 kHz) with the tape select
switch set to the SF/NORM posi-
tion.
Adjust VR102 and VR202 until
the LINE OUT becomes about
—4 dBs.
Playback test tape VTT-675N (1 kHz,
10 kHz) for following adjustment.
1) Adjsut VR101 and VR201 so that
10 kHz signal and 1 kHz signal
gains become flat response.
Adjusting
playback
level
Playback
frequency
response
. Set the cassette deck to its record-
ing mode.
Apply a 1 kHz, approx. —10 dBs
signal to the LINE IN terminals.
Adjust the recording !evel controls
until the signal is available at
—4 dBs at the LINE OUT terminals.
Adjust VR105 and VR205 until
the VU meters deflect to 0.
Record 1 kHz, 50 Hz and 12.5 kHz
signals at an input level of O VU to
—20 aB.
Playback the tape.
Check to see that the 50 Hz and
12.5 kHz singal output deviations fall
within the standard range, using the
1 kHz singal output as a reference.
Adjusting
VU meter
deflection
Checking
record/
playback
frequency
response
Increase in high frequencies
(with a small bias current)
~
Optimum level
Decrease in high frequencies
(with a larger bias current)
12.5kHz
Response (dB)
50Hz 1kHz
Frequency (Hz)
. Apply a 1 kHz, approx. —10 dB
Signal to the LINE IN terminals.
Adjust the recording level controls
until the signal is available at
—4dBs at the LINE OUT termianls.
. After checking to see if the VU
meters become to 0, record the
signal applied to both left and right
channels using normal tape.
. Play back the recording part. Per-
form the recording signal adjust-
ment with VR501 and VR601 so
that the VU meters become to 0.
Adjusting
recording
level
Adjusting | Standard
point value
VR102,
202
VR101,
201
VR105,
205
Adjustment should be performed in the order of steps 1,2,
3, .... Perform this adjustment with the ANRS switch set to
OFF and output level contro! set to maximum.
This adjustment becomes neces-
sary when a change in playback
level results (for example, due to
head replacement).
—4 dBs
(0.5V)
Reference
frequency
\kHz
O0+£2dB at
10kHz
Reference
frequency;
1 kHz
Perform the adjustment when
the parts are replaced.
This checking should be perform-
ed for normal, chrome and metal
tapes and for both right and left
channels.
0+3dB 1. Bias current adjustment for a
at 50 Hz cassette deck should general-
0+3dB ly be performed referring to
the record/playback frequen-
cy response. This is because
the frequency response of a
cassette deck depends more
greatly upon the bias current
than does that of an open
reel deck.
The current measuring
method described below is an
alternative one.
If the bias current is not
properly adjusted, the record
and playback characteristics
becomes as shown left.
at 12.5 kHz
The level difference between
left and right channels for SF/
NORM tape, chrome tape and
metal tape should be less than
1 dB (1 VU). Perform the adjust-
ment usign a normal tape, level
difference between recording
and playback for SA/CrO2 and
metal tapes, should be less than
1.5dB, and that between left and
right channels shold also be less
than 1 dB.

JVC KD-A66 Specifications

General

Brand	JVC
Model	KD-A66
Category	Cassette Player
Language	English