4) Linearity Adjustment
A.Play back the Alignment Tape with SP stairstep (or
monoscope) signal.
B.Observe the signal envelope on an oscilloscope display
triggerd by the switching pulse.
C.Make sure the envelope waveform (in its maximum) out-
put meets the specifications shown in Fig. 5-6.
a. Maximum output of envelope.
b. Minimum output of envelope at the Drum entrance.
c. Minimum output of envelope at the Drum center.
d. Maximum output of envelope at the Drum exit in Fig.
5-6.
Drum Entrance
a
bcd
Fig. 5-9 Waveform Adjustment at the Drum Entrance
c/a30.75, d/a30.63
Fig. 5-6 Envelope Wareform Specification
D.If the section A in Fig. 5-7 does not meet the specifica-
tion, adjust the S-Guide Roller up or down.
E. If the section B in Fig. 5-7 does not meet the specifica-
tion, adjust the T-Guide Roller up or down.
AB
Drum ExitDrum Exit
Fig. 5-7 Adjustment Point
Fig. 5-10 Waveform Adjustment at the Drum Exit
F. After completing adjustment, turn the tracking volume
and make sure the envelope varies almost flat.
G.If the envelope varies as shown in Fig. 5-8, adjustment
of the S-Guide Roller and the T-Guide Roller may be
upset. Therefore, perform the adjustment again.
Fig. 5-8 Abnormal Waveform VariationFig. 5-11 Normal Waveform Variation
33 |
ACEC
DAEWOO
