Reference Values For Electrical Function Confirmation Items; Tape Recorder Section; Reference Values For Confirmation Items; No.mb519)1 - JVC RV-NB10BJ Service Manual

4.2.3 Reference values for electrical function confirmation items

Measurement
Items
conditions
Recording
*Recording and
bias frequency
playback side forward
or reverse
*Test tape :
TYPE
*Measurement
terminal :
BIAS TP on circuit
board
Eraser current
*Recording and
(Reference
playback side forward
value)
or reverse
*Recording mode
*Test tape :
AC-514 and AC-225
Measurement
terminal :
Both of the eraser
head

4.2.4 Tape recorder section

Measurement
Items
conditions
Confirmation
Test tape :
of head angle
TMT7036 (10kHz)
Measurement
output terminal :
Speaker terminal
Speaker R :
headphone terminal
Confirmation
Test tape :
of tape speed
VT712 (3kHz) or
TMT7036 (3kHz)
Measurement
output terminal :
Headphone terminal

4.2.5 Reference values for confirmation items

Measurement
Items
conditions
Wow & flutter
1-28 (No.MB519)
1. While changing over to and from BIAS 1 and 2,
confirm that the frequency is changed.
2. With the recording and playback mechanism, load
the test tape (AC-514 to TYPE
mechanism to the recording and pausing conditions
in advance.
AC-514
3. Confirm that the BIAS TP frequency on the circuit
board is 100kHz
1. With the recording and playback mechanism, load
the test tapes (AC-514 to TYPE
TYPE ), and set the mechanism to the recording
and pausing condition in advance.
2. After setting to the recording conditions, connect
1M in series to the eraser head on the recording
and playback mechanism side, and measure the
eraser current from both of the eraser terminal.
1. Playback the test tape TMT7036 (10kHz).
2. With the playback mechanism or recording &
playback mechanism, adjust the head azimuth
screw so that the forward and reverse output
levels become maximum. After adjustment, lock
the head azimuth at least by half a turn.
3. In either case, this adjustment should be
performed in both the forward and reverse
directions with the head azimuth screw.
<Constant speed>
Adjust VR37 so that the frequency counter reading
becomes 3,010Hz
test tape VT712 (3kHz) with the playback
mechanism or playback and recording mechanism
after ending forward winding of the tape.
When the test tape VT712 (3kHz) has been played
back with the playback mechanism or recording and
playback mechanism at the beginning of forward
winding the frequency counter reading of wow & flutter
should be 0.25% or less (WRMS).
Measurement method
), and set the
6kHz.
and AC-225 to
Measurement method
15Hz when playing back the
Measurement method
Standard Adjusting
values positions
100kHz
6kHz
TYPE
:120mA
TYPE
:75mA
Standard
Adjusting
values
positions
Adjust the
Maximum
head
output
azimuth
screw only
when the
head has
been
changed.
VR37
Tape speed
of decks
: 3,010Hz
15Hz
Standard
Adjusting
values
positions
0.25% or Both the
playback
less
and
(WRMS)
recording
& playback
mechanism