2.3.3 Linearity adjustmenthead. When the ATF of the DVC is off, its tracking op-
eration is effectuated only for the speed control sys-
Procedure of linearity adjustment is shown by the following
tem. Therefore, as time elapses, the DVC gradually
flowchart.
fails in the servo control and it becomes hard to adjust
While triggering an oscilloscope with a signal from pin the linearity.
20 (HID) of CN105 on the MAIN board, observe the Note 4:In practice, if linearity adjustment is performed within
waveform at pin 5 (ENV OUT) of CN105 with the a few minutes after the ATF is switched off, the state
oscilloscope (set for the positive [+] slope). (ATF off) may be left out of consideration, because the
speed servo of the DVC functions when the ATF is off.
Play the alignment tape. Then, turn on the ATF 2.3.4 PB switching point adjustment
(automatic tracking finding) switch for the OVTR deck�
of ORemote control utility� of the SSS software.Procedure of PB switching point adjustment is shown by the
following flowchart.
Make sure that the waveform observed at pin 5 (ENV
Set the alignment tape into the cassette compartment
OUT) of CN105 is linear and parallel as a whole
without extreme drop and irregularity in the level. If the
linearity of the waveform is poor or there is extreme
Start the alignment tape, and the PB switching point of
level drop in the waveform, adjust the guide roller by
turning it with a roller driver.the deck is automatically adjusted by the OVTR deck�of
ORemote control utility� of the SSS software.
Turn off the ATF (automatic tracking finding) switch.
Use the OVTR deck� of ORemote control utility� of the
SSS software (Note 4). While observing the waveform
at pin 5 (ENV OUT) of CN105, check to see if the 2.3.5 Head REC current adjustment
parallelism and linearity of the waveform vary as a
whole with change of tracking as shown in Fig. 2-3-2. Procedure of head REC current adjustment is shown by the
following flowchart.
Repeat the above steps While recording the built-in color bar signal (or EE
depending on the situation.picture), adjust the OHead REC current� of the OVTR
deck� of theORemote control utility� to be the value
Check to see whether the P.B. (420 mV) specified
ENV. waveform is ideally
Nostable and it ideally varies with
change of tracking, or not.
Check the error rate while playing back the
that was adjusted for Ohead REC current� in recor
Yes
If the P.B. ENV. waveform is ideally stable and it ideally
varies with change of tracking, it is recognizable that While changing the Ohead REC current� data by increasing
the linearity is completely adjusted. Finally, check both and decreasing the value at a unit of 10h, record the built-in
the audio and video waveforms for the linearity while color bar signal (or EE picture) for 1 minute each. Note 5
playing back a previously recorded tape.
CH1
HID waveform Check the error rate while playing back the recorded
CH2parts whose data of Ohead REC current� were changed.
Adjust for
PB ENVparallel
waveform
level change.
Fig. 2-3-2 If the observed error
rate is minimum (approximation to the
standard value), it is considered that the
Note 3:In case of the VHS tape recorder, the first tracking pointNo REC current adjustment is complete.
can be locked by means of CTL pulse and DRUM FF
Note 6
when the automatic tracking (AT) function is off, be-
cause the VHS tape recorder has an A/C head. There-Yes
fore, the linearity of the VHS tape recorder is adjust-
able even when the AT is off.If the observed error rate is minimum (approximation to
On the other hand, the linearity of the DVC cannot bethe standard value), it is considered that the REC current
adjustment is complete.Note 6
adjusted when the automatic tracking finding (ATF)
function is inactivated, because the DVC has no A/C
2-18 |
ACEC
