Hitachi DV-RV8500E, Service Manual

Page: 57 / 91

5 - 3
Adjustment / Maintenance > Deck Mechanism Adjustment
5-3 Deck Mechanism Tape Transport System Adjustment
The tape transport components were precisely adjusted before the recorder was shipped from the
factory. They do not need to be adjusted except for the following cases:
1) Noise appears on the screen during playback.
2) Tape is damaged.
3) Any of the tape transport components is replaced
If any of the above occurs, or if any of the tape transport components is replaced, first run a E-240
tape and make sure that excessive tape winkling does not occur at the P2/P3 guide rollers, tape run
guideline on lower drum, A/C head or P4 guide post.
If tape winkling occurs at the P2/P3 guide rollers or tape run guideline on lower drum assembly,
turn the height adjustment screws of P2/P3 guide rollers until winkling is eliminated
See “5-3-1 Guide roller height adjustment”.
If tape winkling occurs at the post of P4 base assembly, perform the A/C head height and tilt
adjustments.
See “5-3-2 A/C head adjustment”.
5-3-1 Guide roller height adjustment
(1) Rough adjustment
1) Run a E-240 blank tape, and check the tape
run guideline on lower drum.
2) If the tape rides under the tape run
guideline, turn the guide roller height
adjustment screw to the left to adjust.
3) If the tape is above the tape run guideline,
turn the guide roller height adjustment
screw to the right to adjust.
(2) Fine adjustment
1) Connect oscilloscope CH-1 to the H/SW
terminal on VCR P.C.B, and CH-2 to the RF
terminal.
2) Use CH-1 (H/SW) to trigger the oscilloscope.
3) Play back the alignment tape.
(If the drum assembly is replaced, adjust the
tracking so that the FM output is maximal.)
4) Finely adjust the guide roller height
adjustment screw so that the supply and
take-up portions of RF envelope are flat.
5) Move the tracking in both directions, and
make sure that the FM envelope waveform
drops evenly.
P2/P3 Guide Roller Height
Adjustment Screw
H/SW
(CH1)
H/SW
(VCR P.C.B)
VCR P.C.B
RF
(VCR P.C.B)
CH-1 CH-2
Oscilloscope
RF
(CH2)
Tracking optimized When tracking is moved
in both directions
P2 Guide
Roller Adjust
Adjust the P2/P3 guide roller
height adjustment screws to
flatten the waveform.
P3 Guide Roller Adjust
Fig. 5-3-2 Guide Roller Fine Adjustment
Fig. 5-3-1 P2/P3 Guide Roller Height
Adjustment Screws