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VGA problem

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david707
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david707 posted on Sun, Feb 2 2014 10:04 PM

I am using a PC connected to a BV8-40 using a male to male VGA cable and getting excellent results using 1280x768 (16:10) resolution. For convenience I need to extend the VGA cable by approx 1m, but using either a female to male extension or other cables/couplers, the picture display changes. It is the same format but much smaller and does not fill the screen. Reverting to the original cable all is well.

There is obviously some signal information going missing when using the extensions. Do I require a specific type cable for the purpose?

This is probably not an issue with the TV but any help would be much appreciated.

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TWG
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david707
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I am using a 7.5m cable from this company:

http://www.vpi.us/pdf/vext-thn-xx-mm.pdf

This cable works fine but annoyingly I underestimated the length required by approx 0.5m. Its all routed under carpet now hence the choice of an extension.

The extension cable is here:

http://www.ebay.co.uk/itm/VGA-M-F-Extension-Cable-for-LCD-Monitor-Projector-1m-/130548469258?pt=UK_Computing_CablesConnectors_RL&hash=item1e654b8e0a#ht_2473wt_1088

and the coupler which I tried with another male to male cable:

http://www.ebay.co.uk/itm/New-15-Pin-SVGA-VGA-Female-to-Female-Gender-Changer-Adapter-Connector-/151182227051?pt=UK_Computing_Sound_Vision_Video_Cables_Adapters&hash=item233329b66b#ht_1925wt_1126

Support for WXGA is not stated on either of these accesories yet there is no suggestion that they are not fully wired. I didnt know all VGA cables were not equal. Wires and pins missing? Why? I thought it was a standard.

Thanks

David

tournedos
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david707:
Support for WXGA is not stated on either of these accesories yet there is no suggestion that they are not fully wired. I didnt know all VGA cables were not equal. Wires and pins missing? Why? I thought it was a standard.

The cable manufacturers will take every chance to save a wire, since copper costs a lot. The original VGA specification had a few non connected pins. Later, they were first assigned to "monitor ID" function, and eventually to DDC function, which are used by the display controller and the display to negotiate about their capabilities. I strongly suspect that they have been omitted in your extension cable, therefore the display card/driver in your PC select some lower resolution/refresh rate that will be safe for an "unknown" display.

--mika

david707
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That explains it! I should have questioned why they were so cheap. I will purchase an extension from the same manufacturer and to the same spec as my long cable.

Thanks

David 

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