Sony SLV-495 - VIDEO SYSTEM CHECKS -Vsssssesssssssssececssessessseseseessesens; White Clip;Dark Clip Check (MA-289 Board)

2-3. SERVO SYSTEM CHECK
Unless otherwise specified, set the switches to the following
positions.
* LCHANNEL | switch
* [TAPE SPEED | switch
2-3-1. RF Switching Position Adjustment
(MA-289 Board)
[Adjustment Purpose]
To adjust the link of the A-ch and B-ch of the tape playback outputs.
To make the unit compatible with other tapes and units. If this
specification is not satisfied, the link will appear on the screen and
the screen will be disrupted, etc.
Playback
Alignment tape: SP color bar portion
Measurement point CH1: Video LINE OUT terminal
CH2: CN261 pin © (RF SWP)
Oscilloscope
Specified value 6.5 + 0.5H (410 + 32 psec)
[Adjustment Method]
1) Short-circuit between JS401 and ground on MA-289 board for
about | second to activate the RF switching position adjustment
mode.
Check that “ADJ” is indicated on FL display.
Using the channel + and — buttons, adjust to 410 + 32psec (6.5
+ 0.5H).
Press the PAUSE button.
Press the EJECT button.
2)
3)
4)
5)
Lo ¥—v—+| +
enlarrgement
Vertical sync. signal
CH1
CH2 6.5+0.5H |
(nen PIN ® (410 + 32usec)
RF SWP))
Fig. 7-2-3.
7-3
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.
7-2-2)
Unless otherwise specified, set the switches to the following
positions.
¢ | CHANNEL | switch
© LTAPE SPEED | SWitch p........-.sssssscsessssssscnesssssscsnrentceneeeteenenss
[Checking Sequence]
1) X’tal OSC Check
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-289 Board)
Mode «id Playback id
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 450 + 200mVp-p.
500 + 200mVp-p
H
3,579,545 + 70Hz
Fig. 7-2-4.