JVC KD-A66 - Electrical Circuit Adjustment Procedure (Continued); Distortion, Noise Ratio, and Erasing Coefficient Checks

KD-A66A/B/C/E/J/U
Ca es “point
point value
Checking . Record a 1 kHz, —4 dBs signal to SF/NORM Be sure to perform this adjust-
record/ LINE IN terminals and perform re- tape; ment following bias curret and
playback cording with the VU meter Less than recording level adjustments.
distortion becomes to 0. 2.5%
2. Play back the recorded part. Check SA/CrO2 tape;
the output with a distortion meter Less than 3%
to see if the value conforms to the Metal tape;
standard value. Less than 2%
. Record a 1 kHz, 0 VU signal. SF/NORM, Apply an output (—72 dBs) to
Stop the input by disconnecting SA/CrO2 and the MIC terminals with the
Checking
signal to
noise from the terminal to perform non- Metal tapes; recording level controls set to
ratio in signal recording. More than maximum so that the VU meter
recording/ | 2. Playback the recorded part. 42 dB becomes to 0.
playback Measure the 0 VU 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.
Checking . Apply a 1 kHz signal to the LINE
erasing IN terminals. Adjust the recording
coefficient level controls until the VU meter
becomes to 0.
. Perform recording with the signal
enhanced by 20 dB.
. Erase a part of the recording.
. Measure the output difference be-
tween the erased part and non-
erased part to compare with an
electronic voltmeter.
For the measuring, connect a
band pass filter between the
deck and the electronic volt-
meter.
Input
(1kHz OVU
+ 20dB)
Tape deck
(recording,
erasing)
Electronic
voltmeter
Band pass
filter
More than
65 dB
-a7- | No. 4193