Adjustment Of Cassette Mechanism Section; Arrangement Of Adjusting Points; Electrical Performance; No.mb519)1 - JVC RV-NB10BJ Service Manual

4.2

Adjustment of cassette mechanism section

4.2.1 Arrangement of adjusting points

Azimuth adjust screws

4.2.2 Electrical performance

Measurement
Items
conditions
Adjustment of *Mode :
recording bias Forward or reverse
current mode
(Reference
value)
*Recording mode
*Test tape :
AC-514 and AC-225
Measurement output
terminal :
Both recording and
headphone terminals
Adjustment of Reference frequency :
recording and 1kHz and 10kHz
playback
frequency
characteristics
Test tape :
TYPE
Measurement input
terminal : OSC IN
1. With the recording and playback mechanism,
load the test tapes(AC-514 to TYPE
to TYPE ),and set the mechanism to the recording
and pausing conditions in advance.
2. After connecting 100
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
(REF:-20dB) 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
AC-514
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
VR32
VR31
Head amplifier & mechanism control board
Measurement method
and AC-225
in series to the recorder head,
2dB.
VR37
Adjustment of tape speed
Standard
Adjusting
values
positions
AC-225
LcH
:4.20 A
:VR31
AC-514
RcH
:4.0 A
:VR32
Output
LcH
deviation
:VR31
between
RcH
1kHz and
:VR32
10kH
:-1dB 2dB

(No.MB519)1-27