Pioneer XR-A670 Service Manual page 63

6.2.2 For XR-A370
• Adjustment points and test points are shown in Fig.10, Fig.12 and Fig.13.
Mechanical Adjustment
• Test tape : NCT-111 (3kHz, 30min).
1. Tape Speed Adjustment
No. Mode Test Tape
NCT-111
Deck Ι
1
(Playback : 3kHz)
PLAY
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.
0 dB 30s
0 dB: 315 Hz, 250 nwb/m
30s
315Hz
6.3kHz 10kHz
Adjusting Measurement
Points Points
ADJ. VR on
TAPE TEST
CASSETTE
POINT (Rch)
MECHA
(AF Assy)
(Fig. 10)
AF Assy
Fig.10 Tape Speed ADJ. Point
30s 30s 10s 10s ......................................................................................................... 10s
12.5
315Hz 14kHz
kHz
Fig.11 STD-331E Test Tape
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
(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.
6.3
10kHz 8kHz
4kHz 2kHz
kHz
XR-A670, XR-A370
Tape Speed
ADJ. VR
Cassette
Mechanism
Section
(Side View)
500 250 125
1kHz 63Hz 40Hz
Hz Hz Hz
Remarks
–20 dB
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