Checking Of Loading Back Tension; Checking Of Vs-Rew Back Tension; Checking Of Pinch Roller Press Force - Sharp VL-Z400H-T Service Manual

VL-Z400S-T/H-T
VL-Z500S-S/H-S/E-T/E-S

6-7. Checking of loading back tension

3 to 4V DC, Cassette controller assembly not installed (Mechanism only)
(1) Apply 3 to 4V DC to the loading motor and select the L start mode. (See 8-1.)
(2) Move the swing arm to the S reel table side. At this time, take care not to damage
the gears etc. (See Fig.7.)
(3) Set the reel hub for back tension measurement on the Tu reel table.
(4) Using the dial tension gauge, pull the thread of the reel hub in the direction shown
by Arrow A and check that the tension is within spec.
<Spec>
(If the tension fluctuates, read the center value.)
27.5 ± 7.5mN

6-8. Checking of VS-REW back tension

3 to 4V DC, Cassette controller assembly not installed (Mechanism only)
(1) Apply 3 to 4V DC to the loading motor and select the VS-REW mode. (See 8-1.)
(2) Move the swing arm to the S reel table side. At this time, take care not to damage
the gears etc.
(3) Set the torque gauge in the Tu reel table.
(4) While turning the torque gauge counterclockwise (one turn in three seconds),
check that the torque is within spec.
<Spec>
(If the tension fluctuates, read the center value.)
0.8+0.2/-0.05mN·m

6-9. Checking of pinch roller press force

3V DC, Cassette controller assembly not installed (Mechanism only)
(1) Hook the thread for pinch roller press force measurement over the pinch lever (position A in Fig.8).
(2) Put the mechanism into the PB mode to press the pinch roller against the capstan shaft.
(3) Hook the thread for pinch roller press force measurement over the tension gauge and pull the tension gauge in the direction shown
by Arrow B in Fig.10 so that the pinch roller is slightly separated from the capstan shaft.
(4) Return the pinch roller gradually and read the value indicated when the pinch roller comes in parallel contact with the capstan shaft
(see Fig.9). Check that the read value is within the following spec.
<Spec>
2.1+0.4N
<Note> After measuring the press force of the pinch roller, promptly exit from the PB mode to separate the pinch roller from the capstan
shaft. (If the pinch roller is left pressed against the capstan shaft for a long time, the pinch roller will be deformed.)
A
Fig.8
OK
NG
Fig.9
Move the swing arm
to the S reel table
side.
Fig.7 How to measure the loading back tension
Pinch roller
B
Right guide
Fig.10
12
A
Capstan shaft