Adjustments; Mechanical Adjustments; Electrical Adjustments - Sony XR-7070 Service Manual

SECTION 3
ADJUSTMENTS
3-1. MECHANICAL ADJUSTMENT 3-2. ELECTRICAL ADJUSTMENTS | DECK SECTION
PRECAUTION PB Head Vertical Adjustment
: . ; Proceudre:
1. Wipe the following components with an absorbent cotton 1... Put dhe set ante the PWD PB mode
cloth moistened with alcohol before adjustment: ; ;
PB head Pinch roller test tape
Idler Rubber belt P-4-A100
Capstan
(10 kHz, — 10 dB)
VTVM
2. Demagnetize the PB head using a head demagnetizer.
3. Be careful not to use a magnetized screwdriver.
4. After adjustment is completed, lock the adjustment parts
using screws.
5. Unless otherwise specified, make adjustments at the LINE OUT
specified voltage (14.4 V). CNP906
| L-CH
R-CH
Torque Measurement
Measure the torque at a supply voltage of 14.4 V DC.
2. Turn the screw and check the output peak value. Adjust
the screw so that peak value in channels L and R
coincides within 2 dBu.
Meter reading
25 to 55 g-cm
(0.35 to 0.77 oz:-inch)
55 to 150 g-cm
(0.77 to 2.1 oz-inch)
Torque meter
FWD CQ-102C
FF, REW CQ-201B
|.
3 R 1.5 to 4 g-cm or less L-CH
Bre one) See (0.02 to 0.05 oz-inch or less) peak ae
within
2dB
R-CH
peak
screw =
nae
—-
an
Position L-CH R-CH g
peak peak
3. Check the phase in the PB mode.
Adjustment Location:
test tape
P-4-A100
(10 kHz, — 10 dB)
L-CH 47 kQ oscilloscope
FWD
REV
LINE OUT
Lissajous's waveform on D6
good ae
4. Repeat the above adjustment for the REV PB mode.
5. Check that output level difference between FWD PB mode and
REV PB mode is within 4 dBu.