(No.MB011)1-39
4.6 Electrical performance
4.7 Reference values for electrical function confirmation items
Items Measurement conditions Measurement method Standard values Adjusting positions
Adjustment of
recording
bias current
(Reference
value)
*Mode : Forward or reverse mode
*Recording mode
*Test tape : AC-225
Measurement output terminal
: Both recording and headphone
terminals
1.With the recording and playback
mechanism, load the test tapes(AC-225
to TYPl),and set the mechanism to the
recording and pausing conditions in
advance.
2.After connecting 100Ω 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 VR101 for LcH and
VR201 for RcH so that the recording bias
current values become 4.0 A (TYP l).
AC-225 : 4.20µA LcH : VR101
RcH : VR201
Adjustment of
recording and
playback
frequency
characteristics
Reference frequency : 1kHz and
10kHz (REF : -20dB)
Test tape : TYP l AC-225
Measurement input terminal : OSC IN
1.With the recording and playback
mechanism,load the test tape(AC-225
to TYP l), 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 TYP, adjust VR101 for LcH
and VR201 for RcH so that the output
deviation between 1kHz and 10kHz
becomes -1dB ±2dB.
Output deviation
between 1kHz
and 10kH
: -1dB ±2dB
LcH : VR101
RcH : VR201
Items Measurement conditions Measurement method Standard values Adjusting positions
Recording
bias
frequency
*Recording and playback side
forward or reverse
*Test tape : TYP l AC-225
*Measurement terminal BIAS TP on
P.C.board
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-225
to TYP l), and set the mechanism to the
recording and pausing conditions in
advance.
3.Confirm that the BIAS TP frequency
on the P.C.board is 100kHz ±6kHz.
100kHz
+9kHz
-7kHz
Eraser
current
(Reference
value)
*Recording and playback side
forward or reverse
*Recording mode
*Test tape : AC-225
Measurement terminal Both of the
eraser head
1.With the recording and playback
mechanism, load the test tapes (AC-
225 to TYP l), and set the mechanism
to the recording and pausing condition
in advance.
2.After setting to the recording
conditions,connect 1MΩ in series to
the eraser head on the recording and
playback mechanism side,and
measure the eraser current from both
of the eraser terminal.
TYP : 75mA
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