JVC HX-Z1R Service Manual page 27

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Electrical Performance
Items
Adjustment of
recording bias
current
(Reference
Value)
Adjustment of
recording and
playback
frequency
characteristics
Reference Values for Electrical Function Confirmation Items
Items
Recording
bias
frequency
Eraser
current
(Reference
value)
Measurement
conditions
Mode: Forward or
1 With the recording and playback
reverse mode
Recording mode
Test tape
: AC-514 to TYPE
and AC-225 to
2 After connecting 100
TYPE
Measurement output
terminal
: Both recording and
3 After resetting the [PAUSE] mode, start
headphone terminals
Reference frequency
1 With the recording and playback
: 1kHz and 10kHz
(REF.: -20dB)
Test tape
: AC-514 to TYPE
Measurement input
2 While repetitively inputting the reference
terminal
: OSC IN
3 While recording and playback the test tape
Measurement
conditions
Forward or reverse
1 While changing over to and from BIAS 1
Test tape
: TYPE (AC-514)
Measurement
2 With the recording and playback
terminal : BIAS TP on
P.C. board
3 Confirm that the BIAS TP frequency on the
Forward or reverse 1 While recording and playback mechanism,
Recording mode
Test tape
: AC-514 to TYPE
and AC-225 to
TYPE 2 After setting to the recording conditions,
Measurement
terminal : Both of the
eraser head terminals
Digitized in Heiloo Netherlands
Measurement method
mechanism, load the test tapes (AC-514 to
TYPE and AC-225 to TYPE
the mechanism to the recording and
pausing condition in advance.
in series to the
recorder head, measure the bias current
with a valve voltmeter at both of the
terminals.
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
mechanism, load the test tapes (AC-514 to
TYPE ), and set the mechanism to the
recording and pausing condition in
advance.
frequency signal of 1kHz and 10kHz from
OSC IN, record and playback the rape.
in TYPE , adjust VR31 for Lch and VR32
for Rch so that the output deviation
between 1kHz and 10kHz becomes
-1dB 2dB.
Measurement method
and 2, confirm that the frequency is
changed.
mechanism, load the test tape.
(AC-514 to TYPE ), and set the
mechanism to the recording and pausing
condition in advance.
P.C. board is 100kHz 6kHz.
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.
connect 1W in series to the eraser head on
the recording and playback mechanism
side, and measure the eraser current from
both of the eraser terminals.
Standard
Values
AC-225
: 4.20
AC-514
), and set
: 4.0 A
).
Output
deviation
between
1kHz and
10kHz
: -1dB 2dB
Standard
Values
100 kHz
6 kHz
TYPE
: 120 mA
TYPE
: 75 mA
3/29/2018
HX-Z1R
Adjusting
positions
VR31
A
VR31
Adjusting
positions
1-27