Viewsonic N1700w LCD TV tuner and VGA/DVI OSD problems

[EmerJency]

I have a Viewsonic N1700w HDTV LCD display that I've been having some problems with. The tuner mode picture is very dark, hardly can see, and the vga/dvi modes have problems with the On Screen Display. When in tuner or composite modes, I can see and work with the OSD menu, but can't see the channel clearly (have to turn contrast way up, but is dark black and white - no color). When I am in vga/dvi mode, connected to computer, the OSD comes up as a black square in middle of screen, but I can't see menu options. I have to turn contrast to 100% for computer use, but it's bright and useable for general use. I hope someone can help me try to troubleshoot the issue and can upload a copy of the service manual. I can buy some IC's directly from Viewsonic so if I could get the service manual I can do the work myself.

Thanks

EJ

[EmerJency]

Can anyone explain to me what the purpose/function of inverter is in an lcd display. I have a hunch that I need to replace mine since I have to keep the contrast and brightness to 100% to view display.

Thanks

EJ

[Prof Logic]

Hi,

The purpose of an inverter is to convert the DC power supply to AC to power the LCD back light (mini flourecent tubes), normally if the inverter goes faulty you will have brightness and /or contrast problems, check the input voltage to the inverter to make sure this is ok and the brighness control signal from the main board to see if this changes when you increase the brightness control in the menu; if DC power supply voltage looks ok change the inverter board. Watch out for the high volatage on the output of the inverter!
Hope this helps.

Prof Logic

[EmerJency]

Hey Prof;

Thanks for the reply. I will test inverter input voltage to see if there is an issue with the voltages. I guess the inverter wouldn't have anything to do with the issues I'm having with the OSD on VGA/DVI inputs.

Thanks again
EJ

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[adammichaelroach]

I'm having the same problem with my display as post 1