Video System Checks; X'tal Osc Check (Ma-316 Board) - Sony SLV-E850B Service Manual

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3 7 63 1515 0
[Adjustment Method]
Short-circuit between pin 5 (AV ADJ) and 3 (GND) of CN261
1)
for about 1 second to activate the RF switching position
adjustment mode.
2) Check that "AF" is indicated on FL display.
3) Using the program + and – buttons, adjust to 416 ± 32µsec
(6.5 ± 0.5H).
4) Press the PAUSE button.
5) The set goes to the AF switching position adjustment mode.
CH1
CH2
CH1
CH2
(CN261 PIN 2
(RF SWP))
(RP-231)
TE
L 13942296513
6) Check that "AH" is indicated on FL display.
7) Using the program + and – buttons, minimize a chipped portion.
At this time, confirm that a noisy sound is not heard.
8) Press the PAUSE button.
9) Press the EJECT button.
CH2
RF SWP
(CN261 PIN 2 )
(RP-231)
OK
CH1
HF ADJ
(CN341
PIN 1 )
(RP-231)
NG
Should be minimized
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Enlargement
Vertical sync. signal
6.5 ± 0.5H
(416 ± 32 µ sec)
Fig. 6-2-3
RF signal dropout
Fig. 6-2-4
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2-4.

VIDEO SYSTEM CHECKS

For the video system checks, follow the checking procedures given
below as a rule. The color bar video signal supplied from the pattern
generator is used as the video input signal for the video system
adjustment of the recording mode. Check that the signal satisfies
the specified value designated in the "Check of input signal" (Fig.
6-2-2)
Unless otherwise specified, set the switches to the following
positions.
• INPUT SELECT switch ................................................. LINE 1
• TAPE SPEED switch ............................................................ SP
Approx.
1Vp-p
[Checking Sequence]
1) X'tal OSC Check
Approx.
5Vp-p
2) SYNC AGC Check
3) White clip/Dark clip Check
4) Recording Y Level Check
5) Recording Chroma Level Check
6) Playback Level Check
2-4-1.

X'tal OSC Check (MA-316 Board)

Mode
Signal
Measurement point
Measuring instrument
Specified value
Note: A frequency counter should be connected through a buffer
Q Q
amplifier (oscilloscope, etc.) having a high impedance and
3 6 7 1 3
a low capacitance.
[Check Method]
1) Check that the oscillation frequency satisfies the specified value
and that the oscillation voltage is 500 ± 200mVp-p.
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6-3
2 9 9 4 2 8
Playback
Alignment tape: SP Color bar portion
Q211 Emitter
Oscilloscope and Frequency counter
4,433,619 ± 96Hz
1 5 0 5 8 2 9 9 4
500 ± 200mVp-p
4,443,619 ± 96Hz
Fig. 6-2-5
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co
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2 8 9 9