JVC RV-B550BU Service Manual page 17

Adjustment of cassette handling mechanism
Items Condition
Confirmation Test tape: VT-703 (10 kHz)
of head angle Measuring output terminal:
Speaker terminal, speaker (R)
(Load resistance: 4 ),
headphone terminal
Confirmation Test tape: VT-712 (3 kHz)
of tape speed Measuring output terminal:
Headphone terminal
Items to be confirmed and standard values
Items Condition
Difference in Test tape: VT-712 (3 kHz)
speed Measuring output terminal:
between fast- Speaker terminal, speaker (R)
forward and (Load resistance: 4 ),
rewind headphone terminal
Wow and Test tape: VT-712 (3 kHz)
flutter Measuring output terminal:
Headphone terminal
Electronic performance
Items Condition
Confirmation Measuring output terminal:
of output CN34-5 or 7-terminal
preamp base
Test tape: VT-724
Confirmation Measuring output terminal:
of Headphone terminal
reproduction Test tape: VT-739
of frequency
characteristics
Recording Fast-forward or rewind
bias direction:
frequency Test tape: TYPE II (AC-
514)
Measuring terminal: Bias
TP on the base
Method for adjustment
and confirmation
(1) Play back the VT-703 test tape.
(2) Adjust the head azimuth screws so
that the tape playback mechanism
records the maximum output level in
both the fast-forward and rewind
direction.
(3) In all cases, both the fast-forward and
rewind direction should be adjusted
using head azimuth screws.
Adjust VR37 so that the frequency
counter records 3,015 Hz
playing back the end of the VT-712 test
tape (3 kHz) in the fast-forward direction.
Method for adjustment
and confirmation
The difference between fast-forward and
rewind should be less than 60 Hz on the
frequency counter when playing back the
beginning of the VT-712 test tape (3 kHz)
in both directions.
Wow and flutter should be recorded at
less than 0.25% (WRMS) when playing
back the VT-712 test tape (3 kHz) in the
fast-forward direction.
Method for adjustment
and confirmation
Confirm that the output from the CN34-5
or 7-terminal preamp base connector is -
25 dBs 3 dB when playing back the VT-
724 test tape.
Reference value: The output from the
headphone terminal is -7 dB
Confirm that the 10 kHz reproduction
level is -1 dB 5 dB compared to the 1
kHz reproduction level when playing back
the VT-739 test tape.
Switch the bias (beat cut switch) between
1 and 2 to confirm that the frequency
changes. Load the test tape (AC-514 for
TYPE II) into the mechanism and preset
it to the record-pause mode.
Confirm that the bias TP frequency on
the base is 100 kHz 6 kHz.
Standard
value
Maximum
output
Tape speed
15 Hz when of cassette
deck: 3,015
Hz 15 Hz
Standard
value
Less than 60
Hz
Less than
0.25%
(WRMS)
Standard
value
Output of CN34-
5 terminal: -25
dBs 3 dB
Difference
between Lch
4 dB. and Rch: within
3 dB
Difference
between 10
kHz and 1 kHz
should be -1
dB 5 dB.
100 kHz 6 kHz
RV-B550BU
Parts to be
adjusted
Adjust the
head
azimuth
screws
when
changing
the head.
VR37
Parts to be
adjusted
Should be
confirmed
when
changing
the motor.
Parts to be
adjusted
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