Viewsonic drivers vx2252mh
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VGL is a negative rail usually in the range of -5 to -10V. Many T-con board often refer to them as "VGH" and "VGL" (though sometimes also "VG_ON" and "VG_OFF".) VGH is typically +15 to +32V depending on the monitor, and is what is used to turn "On" the transistors in the TFT panel. The 3rd and 4th voltages are generated from "AVDD" mentioned above via charge-pump method. You will find this rail usually near a round inductor and a large diode. Most T-con boards call it "AVDD", but again, the notation may vary. The second voltage is generated (through a boost regulator) from the first/main voltage above and is typically in the range of 10 to 15V.
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The first/main voltage is typically a 3.3V to 5V supply from the main board (sometimes called "Vcc", "Vdd", "3V3", or "5V1" on test points - the notation varies between monitors and is not consistent.) This is what connects to your "F1" fuse and powers everything else on the T-con. contains internal power supplies) that are used for driving the TFT, along with powering the drivers and LVDS transcoder IC. The T-con board generates several voltages (i.e. So let's get you on the right foot with some basics on that. Since you already more or less eliminated the LVDS connector as the problem, that leave the T-con board power supplies. White screen issue typically means either LVDS connection problem or T-con board power supply problem.