DVI to VGA Adapter with LCD panels

By BMET ยท 16 replies
Jan 10, 2004
  1. When the drivers load during boot my second LCD panel (with VGA connector) goes into standby.

    After a couple of weeks fighting with this I connected a CRT monitor to the DVI-to-VGA adapter and it works fine (dual monitor).

    What is this adapter doing to the signal that the LCD can not handle and can I fix it?

    Both of my monitor are SVA 17B's.

    Thanks for any help
  2. Mictlantecuhtli

    Mictlantecuhtli TS Evangelist Posts: 4,345   +11

    Unsupported resolution / refresh rate?
  3. Masque

    Masque TechSpot Chancellor Posts: 1,058

    Have you had the dual LCD setup on this before? It could be finding it as the wrong type of display and you may need to change it.
  4. BMET

    BMET TS Rookie Topic Starter

    I have both monitors and display settings the same. I've used these same settings on my old matrox dual header card (Dual VGA) with no problems.

    This problem happend when I bought a XFX GeForce 5200 with VGA and DVI outputs with the DVI-VGA adapter. I took the card back thinking it was bad. Bought the ASUS and had the same problem.

    Thought it was the MB when I tried it in another computer with dual CRTs and it worked. Put it back in mine and swapted that moniter with a CRT and it works.

    Thats why I think it has something to do with the way the signal comes throught the adapter. That output works during POST and the first part of Windows load though.

    I dont think it's a driver problem anymore??????
  5. Godataloss

    Godataloss TS Rookie Posts: 482

    Does the problem happen with both monitors? swap them and see. If the dvi to vga works with yer crt it should work with your analogue lcd.
  6. Masque

    Masque TechSpot Chancellor Posts: 1,058

    Is there a specific setting on the LCD itself? Seems to me I saw something awhile back on an LCD here at work. I'll have to look into it.........
  7. BMET

    BMET TS Rookie Topic Starter

    The ATI driver page keeps setting the monitor connected through the adapter to a digital flat panel.

    I shut down the system and reconnected the LCD went into the settings and had the option of the type of monitor that was connected.

    I set it to monitor (not FPD) and it worked!!!
    5 seconds later the software caught up and removed the monitor option and set it back to FPD and it stopped working.

    If I can get this driver to run it as a monitor everything would be fine. Just another case of the driver being smarter than it should I guess.

    Attached Files:

  8. Masque

    Masque TechSpot Chancellor Posts: 1,058

    When you click on the FPD button, there should be other choices (though I don't have them specifically on my driver). Are there any that could help you control it? Just a thought.
  9. benoitr

    benoitr TS Rookie


    I think I got the same problem. I just bought an ASUS 9600XT and a Samsung 173T LCD with both DVI and VGA inputs. I also got an old VGA display, a ViewSonic G790.

    I never managed to get the Video card to recognize the LCD throught the DVI connection. The card doesn't seams to realize that there is a display connected on the DVI port. I tried the latest driver from ASUS, ATI and Samsung always the same thing. Everything works fine in Analog port either with the video card VGA port or the DVI port using a VGA/DVI adaptor.

    Conclusion I got a really nice dual screen using VGA connection on both displays but If try to use the DVI port it doesn't work. This is a bit sad since the image quality throught the DVI port is superior.

    A few time I end up having the LCD working but each time the ATI driver was indicating that the FPD was not connected? I was able to use the digital connection until the next display power-off or the next windows shutdown/reboot.

    I start to get a bit desperate and really need help on this.
  10. benoitr

    benoitr TS Rookie


    With the Catalist driver you cannot play with the FPD setting until the driver recognize an FPD Pnal on the DVI connection. If I connect using the VGA/DVI adaptor the LCD work fine but it is considered by the ATI as a monitor. In fact you could even select a resolution not supported by the LCD panel and it will work.

    THe few time I end-up with the digital connection working, the ATI driver was giving me access to the FPD menu, the maximum resolution was fixed to 1280 by 1024. This is what we are looking for meanwhile the connection Icon for the FPD was crossed indicating that it was not physically connected?!?!? This is strange, at the next reboot of the PC I endup with no digital connect and need to revert to the analog connection through the DVI port.
  11. BMET

    BMET TS Rookie Topic Starter

    The FPD button tells me the attributes and the only option they give is "Scale image to panel size"

    I've tried to change the display driver to a standard "Plug in Play" but ATI is still trying to drive it as a FPD and not a standard monitor??

    I dont know much about the DVI stuff yet but your monitor has a DVI-D input and the 9600XT has a DVI-I output?? Dont know the difference. Also heard there is a DVI-A port too.
  12. Godataloss

    Godataloss TS Rookie Posts: 482

    DVI-D (Dual- analog or digital) should work with a DVI-I output.
  13. benoitr

    benoitr TS Rookie

    A DVI connection can be one of three types - DVI-I, DVI-D or DVI-A.
    DVI-I contains both the digital and analog connections, (DVI-D + DVI-A) , it's essentially a combination of DVI-D and DVI-A cables within one cable. The I is for Integrated meaning a combination of both signals D and A.
    DVI-D (like DFP or P&D-D (EVC)) is a digital only connection. If both devices being connected support a Digital DVI connection (DVI-I or DVI-D compatible) and are compatible in resolutions, refresh rates and sync, using a DVI-D cable will ensure that you are using a digital connection rather than an analog connection, without playing around with settings to assure this.
    DVI-A is not often used on any cables but is in fact a DVI-I Cable with the other side have a HDDB15 Connector.

    And than there is single and dual DVI depending on the resolution.

    Dual Link: Dual T.D.M.S. (transition minimized differential signaling) "links". DVI can have up to two TMDS links. Each cable provideo two links each holding three data channels for RGB information with a maximum bandwidth of 165 MHz, which is equal to 165 million pixels per second. Dual-link connections provide bandwidth for resolutions up to 2048 x 1536p.
    Single Link: Single T.D.M.S. link. Each link has three data channels for RGB information with a maximum bandwidth of 165 MHz, which is equal to 165 million pixels per second.
    Bandwidth for a single-link connection supports resolutions of over 1920 x 1080 at 60 Hz (HDTV).

  14. BMET

    BMET TS Rookie Topic Starter

    Well, I unistalled the driver once again and reinstalled with the power connector disconnected. The card works without all that extra control panel stuff that shows the FPD stuff.

    Scared to reboot for fear that it will start all over again and detect a FPD.

    I'm not going to disconnect that connector everytime I start my system.

    If the problem starts over then the card will be RMA'd.
  15. benoitr

    benoitr TS Rookie

    I got it working we the driver in digital mode using the DVI port. Again the same funny thing with the ATI Display Driver. See the attached picture.

    Anybody's explanation is welcomed.

    At the next system reboot I will probably loose the digital connection again.

    BMET, I open a trouble ticket for my card on the ASUS site but it could take a while before I get an answer. I started to think that this is could also be a bad DVI cable. DVI connection are apparently susceptible. I am currently using the cheap cable provided with the display.

    Attached Files:

  16. BMET

    BMET TS Rookie Topic Starter

    I can get this thing to work if I unplug the monitor during boot. When it gets to the login screen I can plug it back in and it will work untill reboot then I have to unplug the monitor again. It's going back. Thanks you'all for your help
  17. BMET

    BMET TS Rookie Topic Starter


    Call them. There open till midnight CST now.

    What type of monitor loads when you loss the signal. Instead of being a pnp monitor mine loads "LCD_17" with a "!". It appears the driver thinks my monitor is digital and not analog. When I try to reinstall the driver for the monitor (in device manager) it installs the pnp driver but, it's to late. Sounds like yours is picking it up as an analog mon intead of the digital, right?
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