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(3) Tape transport system adjustment
<Pre-adjustment>
When the part(s) listed in Table 7-3-1 is replaced, perform
required adjustments by referring to procedures for the
tape transport system. When the part(s) listed in Table 7-
3-1 is replaced, the tape path may be changed and may
damage alignment tape. To prevent this, first run a E-240
tape and make sure excessive tape wrinkle does not occur
at each tape guide.
1. If tape wrinkle is observed at the S, T guide rollers,
turn the S, T guide rollers until wrinkle disappears.
2. If tape wrinkle is observed at the No. 8 guide, perform
the tilt adjustment of the ACE head.
Table 7-3-1
Adjustment
Parts replacement
* Cylinder assembly
*S, T sliders
+ ACE head
+ Pinch Jever assembly
* Capstan motor
* No. 9 guide lever assembly
"Upper inde
« S, T guide rollers
« Tension lever assembly
° FE head
From item 3)
From item 4)
1) ACE head assembly coarse adjustment
* Reel clutch assembly
+S, T reel tables
<Adjustment procedures>
a. Audio head height adjustment
1, Play back the tape recorded in the SP mode.
Observe the surface of the ACE head.
2. Turn the ACE height adjusting screw so that upper
tape edge matches to the upper edge of the audio
head core.
b. ACE head tilt adjustment
1. Play back the tape recorded in the SP mode and
observe running condition of the tape at the lower
flange of No.8 guide.
2-40
2. Turn the ACE tilt adjusting screw until tape
wrinkle is caused at the lower flange of No. 8
guide as shown in Fig. 7-3-4 (A).
3. Tum the ACE tilt adjusting screw counterclock-
wise until the tape travels along the lower flange as
shown in Fig. 7-3-4 (B).
c. Audio head azimuth adjustment
1. Play back the 7 kHz audio signal on the alignment
tape in the SP mode.
2. Connect a millivoltmeter or oscilloscope to the
audio line output terminal.
3. Tum the ACE azimuth adjusting screw to obtain
maximum audio output.
Audio head core
Tape
Controt head core
Fig. 7-3-3
(A)
(B)
Fig. 7-3-4 No. 8 guide rough adjustment
d. ACE head position adjustment
1. Play back the 2 MHz video envelope signal in the
alignment tape in the SP mode. Loosen the ACE
head position securing screw.
2. Insert a slot-type screwdriver into the ACE head
position adjusting slit on the ACE main base and
adjust the ACE main base so that the video
envelope reaches a peak level at the tacking center
position when the channel (tracking) up/down
buttons of VTR are pressed simultaneously.
2) Playback phase adjustment
6. After completion of the adjustment(s), push the
channel (tracking) up/down button and make sure
video envelope variations are almost flat.
Next, play back the 2 MHz SP mode video signal on
the alignment tape and makes the video RF envelope
variations are also flat when channel (tracking) UP/
1. Perform the adjustment according to the methods
stated in the electrical adjustment (servo circuit).
3) Linearity adjustment
1. Play back the LP mode white video signal on the
alignment tape.
DOWN buttons is pushed.
Note:
7. If the envelope varies like NG figures as shown in Fig.
« For models SP mode only, use the 2 MHz (A ch)
7-3-7, perform the adjustment again.
video siganl in the SP mode.
Smooth secondary curves are allowable level.
2. Trigger the scope with the switching pulse to issue
the envelope signal output.
3. Make sure the video envelope waveform (in its
maximum output) meets the specification shown in
Fig. 7-3-5. Again make sure the same by playing
back the SP mode 2 MHz video signal on the
alignment tape. If not satisfied, adjust as follows:
pat ol
4
Oak
dbs qin
Fig. 7-3-7 Abnormal waveform variation
Note:
a= maximum output of the video RF envelope
4) ACE head assembly fine adjustment
a. ACE head height fine adjustment
1. Play back the stereophonic alternative recording
300 - 500 Hz audio signal on the alignment tape.
2. Adjust the ACE height adjusting screw so that the
signal envelope is obtained almost flat.
cv fca
Fig. 7-3-8
b = minimum output of the video RF envelope at the
entrance side
c = minimum output of the video RF envelope at the
center point of cylinder
d= minimum output of the video RF envelop at the exit
side of cylinder
-
c, b, daz 0.75
b, Waz 0.63
cla
0.75
| (Non S-VHS model)
Fig. 7-3-5
4. If the (A) section in Fig. 7-3-6 does not meet the
specifications, adjust the S guide roller in up or down
aieas
Note:
direction.
+ If there is no alignment tape (ST-C6, ST-C7), do not
perform this item "a. ACE head height fine adjust-
ment", and perform the process of the note in item "e.
Audio head height check" described later.
5. If the (B) section in Fig. 7-3-6 does not meet the
specifications, adjust T guide roller in up or down
direction.
{A)
(B)
P|
Fig. 7-3-6
2-41
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