1.
Caution :
No modification of any circuit should be attempted . Service work should only be performed after you are
thoroughly familiar with all of the following safety checks and servicing guide line
2.
Safety Check :
Care should be taken while servicing this LCD display, due to the high voltage used in the inverter circuit.
High voltage is exposed in such areas as the associated transformer circuits .
3.
POWER SUPPLY REQUIREMENTS
The external power converter for this display utilizes AC and DC cords. The AC cord is detachable , but the
DC cord is permanently attached . Any attempt to replace another adapter could result in damage to the display .
4.
LEAKAGE CURRENT HOT CHECK
4-1 Plug the AC cord directly into the AC outlet. Do not use an isolation transformer during this check.
4-2 Connect a 1500 ohm , 10 watt resistor , paralleled with a 0.15uF capacitor between each metallic part
and a good earth ground
4-3 Use an AC voltmeter with 1000 ohm / volt or more sensitivity and measure the AC voltage across the
combination 1500 ohm resistor and 0.15uF capacitor.
4-4 Move the resistor connection to each exposed metallic part and measure the voltage.
4-5 Reverse the polarity of the AC plug in the AC outlet and repeat the above measurement.
4-6 Voltage measured must not exceed 1.5 volt RMS, from any exposed metallic part to the ground. A leakage
current tester may be used in the above hot check, in which case any circuit measured must not exceed 1.0
milliamp. In the case of a measurement exceeding the 1.0 milliamp value, a rework is required to eliminate the
chance of a shock hazard .
To Metal Parts
V
AC VOLTMETER
1500
10W
0.15u
.
Earth Ground
1. Precautions and Safety Notices
1
ViewSonic
Corporation
Co
nfidential
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Do
Not
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VX750
Summary of Contents for VX750 VLCDS27089-1W
Page 39: ...2 3 3 Read DDC data from Monitor 36 ViewSonic Corporation Confidential Do Not Copy VX750...
Page 42: ...2 Display color abnormal 39 ViewSonic Corporation Confidential Do Not Copy VX750...
Page 43: ...3 Monitor can not power on 40 ViewSonic Corporation Confidential Do Not Copy VX750...
Page 44: ...4 Monitor white screen 41 ViewSonic Corporation Confidential Do Not Copy VX750...
Page 45: ...5 Monitor black screen 42 ViewSonic Corporation Confidential Do Not Copy VX750...
Page 46: ...6 Audio noise 43 ViewSonic Corporation Confidential Do Not Copy VX750...
Page 47: ...7 Analog input always shows NO SIGNAL 44 ViewSonic Corporation Confidential Do Not Copy VX750...
Page 48: ...8 Digital input always shows NO SIGNAL 45 ViewSonic Corporation Confidential Do Not Copy VX750...
Page 67: ...11 PCB Layout Diagrams Main Board 64 ViewSonic Corporation Confidential Do Not Copy VX750...
Page 68: ...65 ViewSonic Corporation Confidential Do Not Copy VX750 Main Board...
Page 69: ...66 ViewSonic Corporation Confidential Do Not Copy VX750 Main Board...
Page 70: ...Main Board 67 ViewSonic Corporation Confidential Do Not Copy VX750...
Page 71: ...68 ViewSonic Corporation Confidential Do Not Copy VX750 Main Board...
Page 72: ...69 ViewSonic Corporation Confidential Do Not Copy VX750 Control Board...