Mechanical Adjustment; Electrical Adjustment - Yamaha GX-505 Service Manual

"MECHANICAL ADJUSTMENT"

Item to be
Step Tape
Adjusted
1 Check each CT-160L (FF, REW)
torque
TW-2111A (FWD)
TW-2121A (RVS)
2 Check FF, REW AC-514 (C-60)
take up time
3 Azimuth MTT-114N
10kHz, –10dB
4 Tape Speed MTT-111N
3kHz, –10dB
5 Wow/Flutter MTT-111N
3kHz, –10dB
Azimuth
adjustment
screw. (FORWARD)

"ELECTRICAL ADJUSTMENT"

Use 560 mV (250 nwb/m) for 0 dB as the standard level of the unit.
0dB = 250 nwb/m (315 Hz) = – 7 dBV (Rec out level)
< Playback section >
Item to be
Step
Adjusted
Playback
MTT-212N
1 level (315Hz)
315Hz,
250nwb/m
Confirmation of Test tape for frequency check.
playback frequency 3180µs + 120µs (LH) (MTT-256)
2
response 3180µs + 70µs (CrO
PLAYBACK FREQUENCY RESPONSE
± 3dB
± 4dB
50 250 315
Instrument
Mode
required
Torque FF REW
meter
PLAY
FF REW
ACVM PLAY
Oscilloscope
Frequency PLAY
counter
Wow/flutter PLAY
meter
Azimuth
adjustment
screw. (REVERSE)
Fig. A
Instrument
Tape
required
ACVM
ACVM
Oscilloscope
) (MTT-356)
2
± 3dB
± 3.5dB
1k 3k 10kHz 12.5kHz
Adjustment
Rating
part
FF, REW torque : within 70—160g/cm.
Take up torque : 30—60g/cm.
Back tension : 1.5—6g/cm.
80 to 120 seconds.
Azimuth Playback output of L and R is maxi-
adjustment mum and phase difference should
screw. (Fig. A) be minimum both directions. (Fig. B)
3000Hz ± 15Hz
VR7
Less than 0.19% (WRMS)
Rec out L : ch 1
Rec out R : ch 2
DC input, X-Y (Resurge) mode
OK
0.2V
Points of Adjustment
Mode
measurement parts
REC OUT
PLAY
VR4 (L ch)
VR1 (R ch)
PLAY REC OUT
Fig. C
GX-505/GX-505VCD
Remarks
After the adjustment
make sure to apply
screw lock paint.
Perform adjustment at
the center of the test
tape, if possible.
Confirm at center of
the test tape, if possi-
ble.
NG
0.2V
Fig. B
Rating
– 7 dBV ± 0.3 dBV
Check that the 10kHz playback
level is within 0 ± 3 dB of the
1kHz playback level. (Fig. C)
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