Hitachi DV-RV8500E, Service Manual

Page: 58 / 91

5 - 4
Adjustment / Maintenance > Deck Mechanism Adjustment
5-3-2 A/C head adjustment
(1) Rough adjustment (height adjustment and tilt adjustment)
(Play back the alignment tape: Perform this
adjustment only if no audio signal is output.)
1) Make sure that the A/C head base assembly
satisfies the specifications in Fig. 5-3-3(a).
2) Run a E-240 blank tape and make sure that
no curling or winkling of tape occurs at the
lower flange of P4 guide post [see Fig. 5-3-
3(c)].
3) If curling or winkling occurs, slowly turn tilt
adjustment screw (C) to precisely adjust [see
Fig. 5-3-3(b)].
4) Finely adjust height adjustment screw (B)
and tilt adjustment screw (C) so that the
lower edge of tape is positioned at the
bottom of control head as shown in Fig. 5-3-
3(c).
Fig. 5-3-4 A/C Head Fine Adjustment
8.3mm
A/C Head Base
Parallel
(a) A/C head base specifications
A/C Head Ass'y
Azimuth
Adjustment
Screw (A)
Height Adjusting
Screw (B)
Tilt Adjusting
Screw (C)
X-Value
Adjusting Hole
Fixing Screw
P4 Guide Post
Tape
Control Head
0.2-0.25 mm from bottom
edge of tape
(b) A/C head adjustment screws
(c) A/C head height adjustment
(2) Tape transport check between P4 guide post and pressure roller
1) Play back a tape recorded in SP mode.
2) Set to the reverse playback mode, and make sure that no curling or wrinkling of tape occurs
between the P4 guide post and pressure roller.
If curling or wrinkling occurs, slowly turn tilt adjustment screw (C) to precisely adjust [see Fig. 5-
3-3(b)].
(3) Fine adjustment (azimuth adjustment)
1) Play back the alignment tape.
2) Observe the audio output waveform on
oscilloscope.
3) Finely adjust azimuth adjustment screw (A)
so that the audio output level is maximal at
the 1 kHz and 7 kHz audio signals of
alignment tape.
1kHz AUDIO
7kHz AUDIO
Maximize output level.
Maximize output level.
Fig. 5-3-3 A/C Head Rough Adjustment