Mitsubishi Electric HS-U449 Service Manual page 42

3. Interchangeability Adjustment
of the Mechanism
Note 1 : Tracking may need to be preset during
interchangeability adjustment of the mechanism.
Digital tracking is preset by short circuiting TP5A
and TP5B on the PCB-MAIN.
Note 2 : When performing the adjustments in the
PLAYBACK mode, use the staircase signal of an
alignment tape, unless otherwise specified.
Connect an oscilloscope with TP2A (FM
waveform) and externally trigger from TP2H.
3-1. Adjustment of BACK TENSION
and TENSION POLE's Position
Run a blank tape for several minutes to break in the
REEL DISKs and the Tape Running System before the
adjustment.
1. Play back a dummy Tape.
2. Confirm that "A", the distance between the holes in
the TENSION ARM and the MAIN PLATE ASSY
shown in Fig. 3-1-1, is 0.3±0.3 mm.
3. If "A" is not 0.3±0.3 mm, move the hole in the BELT
ADJUSTER in Fig. 3-1-2 within the range shown by
arrow A to set "A" to 0.3±0.3 mm.
4. Set the BACK TENSION measuring jig (code:
859C345O80) and play back the tape.
5. Confirm that "A" shown in Fig. 3-1-1 is 0.0±0.5 mm.
6. If "A" is not 0.0±0.5 mm, repeat this adjustment from
the beginning.
7. Make sure that the indicated value of the BACK
TENSION measuring jig is within 5.4±0.59 mNm.
Note 1 : Check the indicated value of the BACK
TENSION measuring jig after the tape running
condition becomes steady.
Note 2 : Replace the TENSION SPRING if the indicated
value exceeds the specified value.
8. While the tape is running steadily, check visually that
the vibration range of the TENSION POLE is 1 mm or
less. If the vibration range exceeds 1 mm, replace the
REEL DISK.
TENSION ARM
TENSION POLE
A
BELT ADJUSTER
A
Hole
- 29 -
Fig. 3-1-1
BELT ADJUSTER
Fig. 3-1-2