JVC KD-A66 - Adjustment by Computer Tester; Computer Clock and Oscillation Adjustments

KD-A66A/B/C/E/J/U
Computer P.W. Board
meat [ J750
raid VRFOI
( 5 bors For recording level adjustment
(Turning in the direction of the arrow
VRFO2 increases the recording levels.)
(Com —} For reference signal output level
adjustment
VRFO3 poe : 7
| (Turning in the direction of the arrow
( —IKHz —.
increases the output levels.)
—-
ca A/D output adjustment
vreo| {Turning in the direction of the arrow
increases the output levels.)
Clock OSC 400 kHz
Test point
a
Ne ~~)
Adjustment by Computer Tester
Tester for KD-A8 plus Relaying Connection (Using the same quality assurance of the radio cassette recorder)
Adjusting method Adjustment Standard
point (s) value (s)
Adjust
coil
LKO1
with
a
counter
connected
LKO1
400
kHz
to
CLI
on
the
computer
circuit
board
so
that
+5
kHz
this clock pulse is 400 kHz.
Set
the
computer
tester
to
the
TEST
Test
program:
0
2 |Computer
oscillation and MANUAL modes.
2)
Set
the
TEST
MODE
switch
S3
of
the
Computer
computer tester ON, press the PRESET circuit
switch, then set the OPERATION board 307
switch to REC PAUSE.
3) Obtain the switchable output of 1 kHz—
7 kHz—12.5 kHz by pressing the
START switch.
4) With the switchable output set to | kHz,
adjust VRFO3 on the computer circuit
board so that the input level is -37 dB.
5) With the switchable output set to 7 kHz
adjust VRFO2 on the computer circuit
board so that the input level is -36.5 dB.
6) With the switchable output set to
12.5 kHz, adjust VRFOI on the
computer circuit board so thet the
input level is -36.5 dB.
Test point
-37dB
at 1kHz
VRFO3
VRFO2 -36.5dB
VRFO1 ~36.5dB
at 12.5kHz
No.
4193
a4