Denon DN-730R - Manual (Page 8)

IE)N-730ni
ADJUSTING AND CHECKING THE
MECHANISM SECTION
1. Replacing-the Pinch Roller (36)
Before replacing the pjnch 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 (36).
In the playback mgdej^hpok a spring weight opto the bracket at
the center o* the pinch roller. After separating the pinch roller
from the capstan siTaft, 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 (36) when it does not conform to the
standard specification values.
Capstan shaft
\
3. Replacing the Record/Playback Head (14)
(1) How to remove the R/P HEAD.
1) Remove securing screw (1) and azimuth adjusting
screw (1) 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/play back head)
4. Replacing the ERASE HEAD (15)
(1) Unscrew the erase head holding screws (53).
(2) By unsoldering the HEAD W RES can be taken off the
mechanism unit.
(3) When the replacement is completed, secure the screws
with the screw lock.
white ;
5. Checking the Take-up Torque
Load the cassette type torque meter (SONY TW21;1 1).
Check to make sure that the average torque meter reading is
within 30-70 g-crn during playback. If it is not within this range,
check the voltage (approx. 4V) of tha reel motor. If the voltage is
low, the torque will be weak: if it is high, the torque will be strong.
6. Checking the FF and REW Torques
Load the cassette type torque meter (SONY TW2231). Check to
make sure the torque meter indicates within 90—180 g-cm at
the end of FF and REW.
7. Checking the Back Tension Torque During
Record/Playback
Load the cassette type torque meter (SONY TW21 11) : 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 (5) or Washer.
8. Checking the FF and REW Times
Load a C-60 cassette tape (DEMON GR-2/60): check to make
sure the tape is fast forwarded or rewound within 110 sec­
onds. If it is not within this range, check sections 5 and 6.
9. 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 t/pe de­
tection holes on the cassette housina.