Guide Roller Height Adjustment - Sony SVT-RA40 Service Manual

4-3-3. Guide Roller Height Adjustment

1. Playback the Alignment Tape (VHJ-0006) and check
that the envelope waveform is at its maximum at the
tracking centre. Then, after loosening the S guide
roller and the T guide roller by rotating them counter-
clockwise, tighten them in turn until the envelope
waveform becomes flat. If the envelope waveform is
not at its maximum at the tracking centre, refer to
Section 4-3-4 and carry out a rough adjustment of the
horizontal position of the audio R/P head (ACE head)
before adjusting the guide rollers.
2. Adjust the S guide roller.
1 Playback the alignment tape (VHJ-0006). Press the
tracking (_) button, and check whether, when the
envelope waveform has reached 50 % of its
maximum, the front half of the envelope waveform
is flat. If not, fine-tune the S guide roller as
follows.
a. If the front half of the envelope waveform is as
shown in Fig. 4-3-4 (a), this means that you have
pressed the S guide roller too far. Therefore, loosen
it slightly, and when it is in the state shown in Fig.
4-3-4 (b), tighten it again, stopping when the
envelope waveform is flat.
b. If the front half of the envelope waveform is as
shown in Fig. 4-3-4 (b), this means you have not
pressed the S guide roller far enough. Therefore,
tighten it slightly, stopping when the envelope
waveform becomes flat.
c. If the front half of the envelope waveform is as
shown in Fig. 4-3-4 (c), it may happen that when
you tighten the S guide roller, the wrapper wave-
form does not disappear, but sinks into the flat part,
as shown in Fig. 4-3-4 (d). If this happens, the
status shown in Fig. 4-3-4 (c) is normal, so loosen
the S guide roller, then tighten it again until the
envelope waveform is as shown in Fig. 4-3-4 (c).
2 Check that at the tracking centre, the output of the
front half of the envelope waveform is not less than
80 % of the maximum.
3 Rotate the S guide roller 20 d counterclockwise.
3. Adjust the T guide roller.
1 Playback the alignment tape (VHJ-0006,). Press
the tracking (_) button and check whether, when
the envelope waveform is 50 % of maximum, the
back half of the envelope waveform is flat. If not,
loosen the T guide roller slightly, then tighten it
gradually until the back half of the envelope
waveform becomes flat.
2 Check that the output for the back half of the
envelope waveform is at its maximum at the
tracking centre.
2-36
4. Check that the envelope waveform does not fluctuate
when you switch from CUE to PLAY or from REV to
PLAY. If the front half of the envelope waveform does
fluctuate, tighten the S guide roller 1 d to 20 d. If the
back half of the envelope waveform does fluctuate,
repeat steps 3 and 4.
Pressed
Normal
too far
Eccentric screwdriver
(VHJ-0003)
S guide roller
Do not touch
the fixed
screw
The tape should not pass along
the cylinder lead surface
Fig. 4-3-3
If the envelope waveform
is at maximum at the
tracking centre, adjust to
flat.
100 %
(a) S guide roller
pressed too far
50 %
(c) Normal status for
wrapper waveform
50 %
Fig. 4-3-4
Not pressed
far enough
T guide roller
In normal status, the waveform
will be flat even when the en-
velope waveform is reduced to
50 %.
50 %
(b) S guide roller not
pressed far enough
50 %
(d) S guide roller
pressed too far
50 %
SVT-RA40/RA168