Video/Reference Signal System Adjustment; 27 Mhz Vco Free-Running Adjustment; Clock (74 Mhz) Duty Adjustment - Sony HDCU2500 Maintenance Manual

5-3.

Video/Reference Signal System Adjustment

5-3-1.

27 MHz VCO Free-Running Adjustment

Measuring equipment
• Frequency counter
• Oscilloscope
Preparation
• Extend the AT-167A board using an extended board.
• Disconnect the cable from the REFERENCE INPUT connector.
• REFERENCE switch on the panel of AT-167A board → SD
• Connect the measuring equipment as shown in the following figure.
CH2
IN
Probe
Oscilloscope
Adjustment Procedure
Test Point: TP704 (F-4)/ AT-167A board
Adjusting Point: RV701 (F-2)/ AT-167A board
Specification: 27,000,000 ±10 Hz
A B C D
1
2
3
4
5
AT-167A board (Side A )
Setting after Adjustment
After this adjustment is completed, set the switch to the previous state and reconnect the disconnected cable.
5-3-2.

Clock (74 MHz) Duty Adjustment

Measuring equipment
Oscilloscope (20 MHz BWLimit: ON)
HDCU2500
CH2 IN
OUT
Frequency counter
E F G H
RV701
TP704
J
5-7