JVC GY-DV500U - Page 68

Measuring Measuring point (
*
)
No. Item instruments & Mode Adjustment parts (
-
) Adjustment procedure
Input signals Adjustment level (
+
)
2-37
3 Waveform
rise check
• Oscilloscope,
alignment tape
MC-1(NTSC)
MC-2(PAL)
Color bar portion
Eject →Play
Search FWD
→Play
Search REV
→ Play
(1) Switch the mode from Eject → Play and en-
sure that the envelope waveform is restored
in less than 1 sec.
(2) Switch the mode from Search FWD → Play
and from Search REV → Play, and ensure that
the envelope is restored in less than 1 sec. in
both cases.
(3) If the waveform does not restore 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.
* ENV OUT
[jig connector]
* HID [jig connector]
+The envelope
waveform should be
restored within 1
sec.
4 Damage
check
• Self-recorded/
played tape
60ME
Play
↓
Search REV
↓
Search FWD
↓
Play
(1) Transport the self-recorded/played tape from
the beginning by changing modes in order of
Play → Search REV → Search FWD → Play,
and ensure that wrinkles due to strong restric-
tion 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.
* ENV OUT
[jig connector]
* HID [jig connector]
+The tape should not
be damaged by
wrinkle.
5 Envelope
check during
FF/REW
• Oscilloscope,
alignment tape
MC-1(NTSC)
MC-2(PAL)
Color bar portion
FF
REW
* ENV OUT
[jig connector]
* HID [jig connector]
+A > 55µsec.
+B
T/3
(1) Insert the alignment tape and enter Stop mode.
(2) Enter FF mode.
(3) Ensure that the envelope output is present at
55 (s 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.
This checking should be done after complet-
ing the switching point adjustment.
(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
replace as required. Confirm the playback
switching point.
Fig. 2-12-8
MAX
t
T
HIGH
LOW
ENV OUT
HID
ı
Å
2-36