Tape Speed Adjustment - Pioneer XR-A6800 Service Manual

XR-A6800, XR-A4800
QQ
3 7 63 1515 0
6.2.2 For XR-A4800
• Adjustment points and test points are shown in Fig.8, Fig.10 and Fig.11.
Mechanical Adjustment
• Test tape : NCT-111 (3kHz, 30min).

1. Tape Speed Adjustment

No. Mode Test Tape
NCT-111
Deck Ι
1
(Playback : 3kHz)
PLAY
TE
L 13942296513
Electrical Adjustment
Check the following before starting.
(1) Confirm that the tape speed adjustment has been completed.
(2) Clean the heads and demagnetize them using a head eraser.
(3) Set the measurement level to 0 dBV = 1 Vrms.
(4) Use the specified tape for adjustment. Use the labeled (A)
side of the test tape.
STD-331E : For playback check
STD-632 : Normal blank tape
(5) Provide yourself with the following measuring devides:
• AC voltmeter (Noisemeter : filter off)
• AC millivoltmeter
• Low-frequency oscillator
• Attenuator
• Oscilloscope
(6) Adjust both right and left channels unless otherwise specified.
www
0 dB 30s
0 dB: 315 Hz, 250 nwb/m
30s
315Hz
.
6.3kHz 10kHz
58
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Adjusting Measurement
Points Points
ADJ. VR on
TAPE TEST
CASSETTE
POINT (Rch)
MECHA
(AF Assy)
(Fig. 8)
AF Assy
Fig.8 Tape Speed ADJ. Point
x ao
y
30s 30s 10s 10s ......................................................................................................... 10s
i
12.5
315Hz 14kHz
kHz
Fig.9 STD-331E Test Tape
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8
Adjustment Procedure
Press the PLAY SW and adjust so that the reading
becomes 3000Hz ± 20Hz. Confirm that wow & flutter
level is below 0.3% (in the reverse direction, confirm
that the reading is within 3000Hz ± 60Hz).
Front Side
Q Q
3 6 7 1 3
(7) Warm up the unit for several minutes before adjustment.
In particular, be sure to warm up the unit in the REC/PLAY
mode for 3 to 5 minutes before starting recording/playback
frequency characteristics adjustment.
(8) Always follow the indicated adjustment order.
Otherwise, a complete adjustment may not be achieved.
Playback Adjustment (Decks Ι and ΙΙ)
(1) Head Azimuth Adjustment
Recording Adjustment (Deck Ι)
(1) Bias Oscillation Frequency Adjustment
(2) Recording Bias Adjustment
∗ As the reference recording level is 250nwb/m for STD-331E,
the recording level will be higher by 4 dB for STD-331B
(160nwb/m). When adjusting, pay carefull attention to the type
of tape used.
u163
.
6.3
10kHz 8kHz
4kHz 2kHz
kHz
2 9 9 4 2 8
Remarks
Tape Speed
ADJ. VR
Cassette
Mechanism
Section
(Side View)
1 5 0 5 8 2 9 9 4
m
co
500 250 125
1kHz 63Hz 40Hz
Hz Hz Hz
9 9
2 8 9 9
–20 dB