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© Overall gain
Condition:
e Record/playback mode
e Normal tape mode
e Input level controls...MAX
e Standard input level;
MIC
LINE IN
(TAPE [])
—24+4dB
. Test equipment connection is shown in fig. 15.
. Insert the normal reference blank tape (QZZCRA).
. Place UNIT into record mode.
. Supply a 1kHz signal through ATT (—24dB) from AF oscillator, to LINE
IN
Equipment:
e VTVM
e AF oscillator
e ATT
e Oscilloscope
e Resistor (6002)
e Test tape
(reference blank tape)
...QZZCRA for Normal
Record/ playback
' Adjust ATT until monitor level at test points [TP4 (L-CH), TP5 (R-CH)]
becomes 0.42V [0.4V at test LINE OUT jack].
. Playback recorded tape, and make sure that the output level at test
points [TP4 (L-CH), TP5 (R-CH)] becomes 0.42V [0.4V at test LINE OUT
jack].
Record/ playback
TP4 (L-CH)
head
Po (R-CH)
. If measured value is not 0.42V, adjust it by using VR7 (L-CH) or VR8
(R-CH).
. Repeat from step (2).
Condition:
e Record mode
e Input level controls...MAX
Fluorescent meter
(TAPE
)
Playback mode
VTVM
Oscilloscope
Test tape
f
Equipment:
e VTVM
e ATT
e AF oscillator
e Oscilloscope
e Resistor (6002)
. Make connections as shown in fig. 16.
. In the recording pause mode, apply 1kHz (—24dB) to LINE
IN.
. Adjust ATT so that output level at LINE OUT is 0.4V.
. At this time, check that 0dB indicator is lighted halfway
(intermediate brightness between full brightness and light-
out: See fig. 17).
. If the indicator is not lighted halfway as described in step 4,
adjust VR301 (L-CH), VR302 (R-CH).
. Repeat adjustments and checks at steps 3, 4 and 5 two or
three times.
AF oscillator
ATT (ne"iy Record mode
VTIVM
Oscilloscope
Fig. 16
0
dB
-dB
-20 PEAK 10 e 5 3 ms e005
9)
+08
My,
QU)! A
Fig. 17
Condition:
e Record mode
e Input level controls...MAX
Dolby NR circuit
(TAPE [2] )
Equipment:
e VTVM
e AF oscillator
e ATT
e Oscilloscope
e Resistor (6002)
. Test equipment connection is shown in fig. 18.
TP4 (L-CH)
. Place UNIT into record mode, set the Dolby NR switch to OUT position
and supply a 5kHz signal to LINE IN to obtain 17.5mV at TP4 (L-CH),
TP5 (R-CH).
in the IN position are 8 (+2.5)dB greater than the values at the OUT
gp osciliator
position of the Dolby NR switch.
LINE IN
. Confirm that the values at test points TP4, TP5 with Dolby NR switch
Jo of [OOOO]
ATT
60082
Record mode
VTVM_
Oscilloscope
Fig. 138
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