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M@ MEASUREMENT AND ADJUSTMENT METHODES
TP6 Overall Gain Adj.
Main P.C.B.
Input
Point
VR3, 4
Tape
[2] P.B. Gain Adj.
VR1, 2
Tape
[1] P.B. Gain Adj.
TP1 (Mechanism (1))
TP2 (Mechanism (2))
TPN1 (Mechanism (1))
TPN2 (Mechanism (2))
VR301, 302 Tape
[2] Bias Current Adj.
Mechanism (14), (2) P.C.B.
Measurement Condition
¢Input level controls; Maximum
¢ Dolby NR switch; Out
¢ Editing switch; off
Make
sure heads are clean
Make
sure capstan and pressure roller are clean.
e Judgeable room temperature 20+5°C (68+9°F)
Measuring instrument
EVM
(Electronic Voltmeter)
* Oscilloscope
¢ Digital frequency counter
¢ AF oscillator
ATT (Attenuator)
¢DC voltmeter
e Resistor (600Q)
Test tape
* CrO, reference blank tape; QZZCRX
+ Metal reference blank tape; QZZCRZ
* Playback frequency responce (315Hz, 12.5kHz,
10 kHz, 8kHz, 4kHz, 1kHz, 250Hz, 125Hz, 63Hz,
—20dB); QZZCFM
Output point
Normal speed
1. Test equipment connection is shown in Fig. 3.
Output point
High speed
Oigital frequency
counter
Playback frequency response (TAPE [i], [2))
1. Test equipment connection is shown in Fig. 4.
+6aBt
dt
+
Hy
in I
\
yt
:.
aa
(|
Output Point
oi
Ht t+
a
rr
a
—6dBb-——+
;
i
| !
14
Li
i
63H2z 100Hz
315Hz Tr
kHz
2kHz
4kHz
8kHz 12.5kHz
Fig. 5
200Hz
500Hz
Fig. 4
Playback gain adjustment (TAPE [1], [2))
1. Test equipment connection is shown in Fig. 4.
2. Playback the playback gain adjusted part (315Hz, 0dB) of the test tape (QZZCFM).
3. Adjust TAPE [1]: VR1 (L-CH) {VR2 (R-CH)} and TAPE [2]: VR3 (L-CH) {VR4 (R-CH)} so that the output is within
Overall frequency response (TAPE [2))
1. Test equipment connection is shown in Fig. 6, and connect a
jumper of TP6. (See page 9).
6. After adjustment, cut a jumper of TP6.
Input Point
Overall gain adjustment
(TAPE [2))
6. After adjustment, cut a jumper of TP6.
Ow
mo
ie
:
+ 0.1
| Standard value: 0.4V | y08Y
|
Dolby NR circuit
1. Test equipment connection is shown in Fig 9.
2. Set a normal
tape and apply 5kHz
signal
in record
pause
mode.
[ Standard value: 8+1.5dB
m@ MICRO
(IC801:
Terminal
No.
fe i
= =
=
N
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