SHARP VL-SD20H
Manual de Servicio

VL-SD20S/H/E
<REW back tension standard> (If the tension fluctuates, read its center value.) 15 ± 15 mN (1.5 ± 1.5gf )
10 1.0

VL-SD20U

6-8. Checking of winding Tu reel base ratchet torque
DC3V, without cassette controller assembly (Independent Mechanism) (1) Remove the cassette controller assembly, then apply DC3V to the loading motor and put the system into standby mode. (refer to 8-1) (2) Move the swing arm toward the S reel base side. Be careful not to prevent damage to the gears and other parts all this while. (Fig. 8) (3) Set a back tension measurement reel hub on the Tu reel base. (4) Using a dial tension gauge, pull the string in the A direction, then confirm that the tension is within the standard. <Winding Tu reel base ratchet torque standard > (If the tension fluctuates, read its center value.) 90mN or less (9gf or less )

Move the swing arm toward the S reel base side.

A

6-9. Checking of rewinding playback (VS-REW) back tension
DC3V, without cassette controller assembly (Independent Mechanism) (1) Remove the cassette controller assembly, then apply DC3V to the loading motor and put the system into rewinding playback (VS-REW) mode. (refer to 8-1) (2) Move the swing arm toward the S reel base side. Be careful not to prevent damage to the gears and other parts all this while. (3) Set a torque gauge on the Tu reel base. (4) Turning the torque gauge to counterclockwise (1 turn for 3 seconds), then confarm that the torque is within the standard. <Rewinding playback (VS-REW) back tension standard value> (If the tension fluctuates, read its center value.) 0.70 ± 0.35mN·m (7.0 ± 3.5gf·cm)

Fig. 7. Loading back tension measurement method

6-10.Checking of pinch pressing force
DC3V, without cassette controller assembly (Independent Mechanism) (1) Set the pinch roller pressing force measuring thread on the pinch lever (position A , Fig. 9). (2) Set the mechanism to the playback mode, press the pinch roller against the capstan axis. (3) Fit the tension gauge to the pinch roller pressing force measuring thread, pull in the arrow B direction shown in Fig. 11 to separate a little the pinch roller from the capstan axis. (4) Gradually return the pinch roller, and when the pinch roller contacts parallel the capstan axis, read the value (see Fig. 10) to make sure that the value conforms to the standard shown below. <Standard> 1.8 ± 0.3N (180 ± 30gf) <Caution> After making this measurement, quickly release the system from playback mode and remove the pinch roller from the capstan shaft. (If the pinch roller is left fitted onto the capstan shaft for a long time, the pinch roller will be deformed.)

Move the swing arm toward the S reel base side.

A

Fig. 8. Winding Tu reel base ratchet torque measurement method

Pinch roller

Capstan shaft

Right guide

A

B
OK NG

Fig. 9

Fig. 10

Fig. 11

6-3