Adjusting And Checking The Mechanism Section - Marantz SD555 Service Manual

2. ADJUSTING AND CHECKING THE MECHANISM SECTION
1. Replacing the Pinch Roller
Before replacing the pinch roller, clean the tape contact surface
of the pinch roller and the capstan shaft.
Most causes of poor tape transport can be traced to dirty pinch
roller and capstan shaft.
Remove the clips that press the pinch roller and pull the pinch
roller forward to remove it.
After replacing, run a padless C-90 tape to check for tape curls
at the tape guide section of the head.
2. Checking the Pressure Force of the Pinch
Roller
In the playback mode, hook a spring weight onto the bracket at
the center of the pinch roller. After separating the pinch roller
from the capstan shaft, allow the pinch roller to contact the caps-
tan shaft again. Check to make sure the spring weight reads be-
tween 250 ~350 g when the pinch roller starts to rotate.
Replace the pinch roller when it does not conform to the standard
specification values.
Capstan shaft
f
3. Replacing the Record/Playback Head
(1) How to remove the R/P HEAD.
1) Remove securing screw and azimuth adjusting screw
from the record/playback head.
2) Remove the soldered head wire and disassemble the
mechanical unit to remove the record/playback head.
(2) How to assemble the R/P HEAD.
Reverse the above (1) procedures for removing the R/P
HEAD.
* Solder the HEAD WIRE according to the diagram.
mechanism (recording/playback head)
4. Checking the Take-up Torque
Load the cassette type torque meter (SONY TW2111).
Check to make sure that the average torque meter reading is
within 30-70 g-cm during playback.
5. Checking the FF and REW Torques
Load the cassette type torque meter (SONY TW2231). Check to
make sure the torque meter indicates within 80~170 g-cm at
the end of FF and REW.
6. Checking the Back Tension Torque During
Record/Playback
Load the cassette type torque meter (SONY TW2111); check
to make sure the torque meter reads between 2 ~6 g-cm during
playback and that there is no unevenness.
If it is not within this range, replace the reel ass'y or Washer.
7. Checking the FF and REW Times
Load a C-60 cassette tape check to make sure the tape is fast
forwarded or rewound within 120 seconds. If it is not within this range,
check sections 5 and 6.
8. Checking the Existence of a Cassette
Housing and the Operation of the Erase
Prevention, Metal and Chrome Switch
Confirm that the sensor arm properly detecting the tape type de-
tection holes on the cassette housing.
PCS 87 611
:
|
!