8
XVM-H6
SECTION 3
ELECTRICAL ADJUSTMENTS
When measuring, the ground should be connected to the ground (frame of 15-pin connector connected to external device) in the monitor
board unless otherwise specified.
3-1. EQUIPMENT USED
The following measuring equipment are used for these electrical adjustments:
• Oscilloscope
• NTSC pattern generator
• Stabilized power supply
• Digital voltmeter
• Frequency counter
• Connection box (XA-116)
3-2. CONNECTION OF EQUIPMENT
3-3. 5V ADJUSTMENT
1. Display gray scale on the monitor screen.
2. Connect digital voltmeter to the C320 position of L305.
3. Adjust VR+5 so that the reading on the voltmeter stands at the specified value.
Specified value: 5.00 ± 0.05 V
3-4. FREQUENCY ADJUSTMENT
This frequency adjustment on the DC-DC converter is only performed if there is switching noise mixed on the screen.
Adjust the semi-fixed resistor VFRQ to a position in which no noise appears on the screen.
3-5. PLL FREE RUN FREQUENCY ADJUSTMENT
1. Make the input signal no signal.
2. Connect frequency counter to pin 56 of IC U2.
3. Adjust the semi-fixed resistor VFREQ until the frequency is at 15895 ± 20 Hz.
VIDEO IN
VIDEO
G
N
D
B+
NTSC
pattern generator
connection box
XA-116
monitor
XVM-H6
stabilized
power supply
14.4V
