Switching Position Adj; Slow Tracking Confirm And Adj - Sony SVT-N72P Service Manual

3-1-3. Switching Position Adj.

Measuring Point Measuring Equipment
TP101(VIDEO Oscilloscope
OUT terminal)
TP183 (SW-P)
Adj. Location
REC button, TRACKING
buttons, EJECT button
1. Play back the alignment tape. Press the TRACKING
buttons (+) and (_) simultaneously. (TRACKING
center position)
2. Press the REC button three times within 10 seconds
after the display is shown. All three presses must be
carried out within 3 seconds. For the third time, press
the REC button more than 0.5 seconds as shown in
Fig. 2-1-2.
3. The automatic adjustment mode is set, the numerals of
Indicator display "P 0 : 00" changes automatically and
the unit stops at the point the adjustment value be-
comes approx. 6.5 H.
4. In the same adjustment mode, trigger at the edge of the
RF SW pulse, and check that the front edge of the V
sync signal from the fall edge of the RF SW pulse is
delayed by 6.5 H ± 0.5 H as shown in Fig. 2-1-3. If it is
not 6.5 H ± 0.5 H, manually perform fine adjustments
for the TRACKING buttons (+) or (_) to satisfy the
specification.
5. After completing adjustments, press the EJECT button
(more than 1 second) and check the Indicator shows "P
– –" at this time.
n
Repeat steps 1 to 4 if the adjustment takes more then 20
seconds.
REC button
Start of play
back display
ON
OFF
withi
withi
2 sec.
10 sec.
Fig. 2-1-2
3-2
Adj. Condition
PLAY (3 H) mode
Alignment tape
VHJ-0009
Adj. Value
6.5 H ±0.5 H
more
then
adjusting
0.5
period 10 sec.
sec.
3-1-4. F. Slow Tracking Confirm and Adj.
Measuring Point Measuring Equipment
Picture of Color-bar generator
monitor TV (Monoscope pattern
signal), Monitor TV
Adj. Location
REC button
TRACKING buttons
EJECT button
1. Insert blank VHS cassette tape and record monoscope
pattern on the 3 H mode.
2. Play back the self-recorded tape and then set the VCR
in the STILL mode.
3. Change to F. Slow play back mode by pressing REC
button 3 times. These 3-push must be done within 3
seconds, and last push must be kept pressed for 0.5
seconds.
4. Set the tracking control position to the center by
pressing TRACKING (+) and (_) buttons simulta-
neously, and confirm the absence of noise in the slow
playback image on the monitor screen at this centered
tracking position. Starting from this centered tracking
position, push the (+) and (_) buttons and confirm that
no noise appears before the fifth push in either direc-
tion.
If noise appears before the fifth push, fine-tune with
the front tracking adjustment button so that no noise
appears before the fifth push, then press the EJECT
button to make this point the new tracking center.
(When pressing the EJECT button to enter this new
tracking center, the tracking should be displayed.)
The FLD counter readout changes to "P – –" for
approximately 1 second in order to confirm that data
has been entered.
T = 6.5 H ±0.5 H
1 H
Fall
RF.SW.PULSE
Fig. 2-1-3
Adj. Condition
Self-recording
(3 H) mode, PLAY
mode, Blank tape
Adj. Value
—
0.5 H
Front edge of
vertical sync signal
SVT-N72P (E)