JVC GY-DV5000U Service Manual page 54

Measuring
No. Item instruments &
Input signals
3 Waveform • Oscilloscope,
rise check alignment tape
MC-1(NTSC)
MC-2(PAL)
Color bar portion
4 Damage • Self-recorded/
check played tape
60 ME
270ME
5 Envelope • Oscilloscope,
check during alignment tape
FF/REW MC-1(NTSC)
MC-2(PAL)
Color bar portion
ENV OUT
HID
2-30
Measuring point ( * )
Adjustment parts ( - )
Mode
Adjustment level ( + )
* ENV OUT
Eject →Play
Search FWD [REWRITE board]
* HID [REWRITE board]
→Play
+The envelope
Search REV
→ Play waveform should be
restored within 1
sec.
* ENV OUT
Play
↓ [REWRITE board]
* HID [REWRITE board]
Search REV
+The tape should not
↓
Search FWD be damaged by
↓ wrinkle.
Play
* ENV OUT
FF
REW [REWRITE board]
* HID [REWRITE board]
+A > 55µsec.
+B
T/3
ı
t
Å
T
Fig. 2.9.6
Adjustment procedure
(1) Switch the mode from Eject → Play and en-
sure that the envelope is stabilized in less than
1 sec.
(2) Switch the mode from Search FWD → Play
and from Search REV → Play, and ensure that
the envelope is stabilized in less than 1 sec. in
both cases.
(3) If the envelope does not stabilized in the speci-
fied period, fine-adjust the supply/take-up
guide rollers as far as the envelope waveform
specification is met, then restart checking from
the above procedure (1) again.
(1) Transport the self-recorded/played Mini cas-
sette tape from the beginning by changing
modes in order of Play → Search REV →
Search FWD → Play, and ensure that wrinkles
due to strong restriction by the guide rollers
and guide pole are not produced on tape.
(2) Perform the same check at the section near
the end of tape.
(3) Make sure that no tape damage occurs when
a tape is being loaded, unloaded or ejected.
(4) Perform the same produre (1) — (3) with stand-
ard cassette.
This checking should be done after completing the
switching point adjustment.
(1) Insert the alignment tape and enter Stop mode.
(2) Enter FF mode.
(3) Ensure that the envelope output is present at
55 µs before the HID switching timing.
(4) Check the take-up side of the envelope to see
that the MAX output duration is more than 1/3
the HID duration.
(5) Enter REW mode and check the same items
as (3) and (4) above.
(6) If the envelope is out of specification, check
the tension band and main brake assembly and
MAX
replace as needed. Confirm the playback
switching point.
HIGH
LOW