JVC RV-NB10BB, Service Manual

Page: 27 / 103

(No.MB519)1-27
4.2 Adjustment of cassette mechanism section
4.2.1 Arrangement of adjusting points
4.2.2 Electrical performance
Azimuth adjust screws
VR32
VR31
VR37
Adjustment of tape speed
Head amplifier & mechanism control board
Measurement
conditions
Measurement method
Standard
values
Adjusting
positions
1. With the recording and playback mechanism,
load the test tapes(AC-514 to TYPE and AC-225
to TYPE ),and set the mechanism to the recording
and pausing conditions in advance.
2. After connecting 100 in series to the recorder head,
measure the bias current with a valve voltmeter at
both of the terminals.
3. After resetting the [PAUSE] mode, start recording.
At this time, adjust VR31 for Lch and VR32 for Rch
so that the recording bias current values become
4.0 A (TYPE ) and 4.20 A(TYPE ).
1. With the recording and playback mechanism, load
the test tape(AC-514 to TYPE ),and set the
mechanism to the recording and pausing condition in
advance.
2. While repetitively inputting the reference frequency
signal of 1kHz and 10kHz from OSC IN, record and
playback the test tape.
3. While recording and playing back the test tape in
TYPE ,adjust VR31 for LcH and VR32 for RcH so
that the output deviation between 1kHz and 10kHz
becomes -1dB 2dB.
Adjustment of
recording bias
current
(Reference
value)
Adjustment of
recording and
playback
frequency
characteristics
*Mode :
Forward or reverse
mode
*Recording mode
*Test tape :
AC-514 and AC-225
Measurement output
terminal :
Both recording and
headphone terminals
Reference frequency :
1kHz and 10kHz
(REF:-20dB)
Test tape :
TYPE AC-514
Measurement input
terminal : OSC IN
AC-225
:4.20 A
AC-514
:4.0 A
Output
deviation
between
1kHz and
10kH
:-1dB 2dB
LcH
:VR31
RcH
:VR32
LcH
:VR31
RcH
:VR32
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