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TD-MXG9BK
3. Electrical Adjustments
(Make the following adjustments after adjusting the head azimuth.)
In principle, the adjustments should be made in the following sequence.
Set the NR switch to OFF and the BEAT CUT switch to "1°.
Adjustments marked with an asterisk (*) should always be made after the head is replaced
OdBs = 0.775V.
* |Standard Jevel}1. Connect an electronic voltmeter to the DOLBY
DeckA
1) The playback level varies when
{Playback
Level)
Playback
Frequency
Response
Tape
1. Connect a frequency counter to the VCR REC
1) Adjust the normal speed first,
Speed
_
QUT and play back VTT-712.
Vv
3,000 Hz
and perform the hign speed
.
+1QHz
adjustment
:
. Normal speed Adjustment
.
.
1} Mechanism B
:
.
play back deck B to adjust the semi-fixed
.
;
resistor VR4510n ENJ-067-1.
. Hign-speed adjustment
1) Mechanism A
0000 Hz
play back deck Aand adjustthesemi-fixed
|
_ |
£20Hz |
resistor VR4520n ENJ-067-2.
3
TP (figure 3).
L; VR111
-5.5dBs
the head is replaced so should
Play back VTT-724 (1 kHz: ~4dBs) to adjust
ReVRI12 | (411mV) | be adjusted.
gi
:
Deck 8
Use an electronic voltmeter
the semi-fixed resistors.
Ls VRI44
+10B
with an impedance of 100 kQ
R: VR142
or more.
. Connect an electronic voltmeter to the DOLBY
Beck A
TP (figure 3).
Li VR113
-141.5dBs
R:VR114 | (206mV
. Play VTT-703L (10kHz: - 10dBs) and adjust
EDN
semi-fixed resistors to obtain the standard
Deck B
+308
values
L; VR143
R: VR144
Adjustment
| 1 . Connect an electronic voltmeter to the R3G7(L},;
130740)
Recording
Bias
.
Frequency
Record / Play
Frequency
Response
(Bias current}
Response
(dB)
R308(R) at either end, and record the no
L302{R)
signal Metal tape .
. Adjust to the liast Volues.
. Connect a frequency counter to the BIAS
100 kHz
[Set the BEAT CUT SWITCH to "1"
TP(figure 3),and perform a recording to adjust
. £5 kHz
:
bias frequency .
. Supply 1kHz and 12.5kHz with 30mV signals to
Refer to figure 2 below.
VCR terminals respectively to record them.
L:VR301
| 043 dB
|1) The recording and playback ~
:
for
frequency
response of a
, Connect an electronic voltmeter to the DOLBY
R: ¥R302
12.5 kHz
pinot Rigi adjusted by
TP (figure 3) to confirm the recorded values.
with 1 kHz
adjusting the bias current.
. If the values are not satisfied , adjust the semi-
as the
Perform the adjustment with
fixed resistors and record the signals again to
standard.
normal tape and confirm that
contirm the values.
the values are within the
range for CrO2 tape.
With a small bias current
Optimum level
VR3O1{L)
.
VR302{R)
' Decreasing
{oe
Increasing
+)
f
in high frequency
me
in high frequency-
With a large bias current.
Figure 2
100Hz ~
ikHz
12.5kHz
_ ~oFrequency
1-10(No.20437)
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