Video System Checks; X'tal Osc Check (Ma-327 Board); Sync Agc Check (Ma-327 Board); Recording Y Level Check (Ma-327 Board) - Sony SLV-777HF Service Manual

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
[Checking Sequence]
1) X'tal OSC Check
2) SYNC AGC Check
3) Recording Y Level Check
4) Recording Chroma Level Check
5) Playback Level Check

2-4-1. X'tal OSC Check (MA-327 Board)

Mode Playback
Signal Alignment tape: SP Color bar portion
IC201 pin %§
Measurement point
Measuring instrument Oscilloscope and Frequency counter
Specified value 3,579,545 ± 70Hz
Note: A frequency counter should be connected through a buffer
amplifier (oscilloscope, etc.) having a high impedance and
a low capacitance.
[Check Method]
1) Check that the oscillation frequency satisfies the specified value
and that the oscillation voltage is 500 ± 200mVp-p.
3,579,545 ± 70Hz
Fig. 6-2-5.
500 ± 200mVp-p
6-4

2-4-2. SYNC AGC Check (MA-327 Board)

Mode E-E
Signal Color bar
IC201 pin #•
Measurement point
Measuring instrument Oscilloscope
Specified value A=2.10 ± 0.10Vp-p
[Check Method]
1) Check that the Video signal level (A) satisfies the specified
value.
White (100%)
Fig. 6-2-6.

2-4-3. Recording Y Level Check (MA-327 Board)

Mode E-E (SP)
Signal No-signal
IC201 pin !•
Measurement point
Measuring instrument Oscilloscope
Specified value A=290 ± 70mVp-p
[Check Method]
1) Check that the recording RF signal satisfies the specified value.
Fig. 6-2-7.
A
H
A