DWW-7VGA won't display image

guf · 05-08-2004, 06:06 PM

Hello,

I have bought a DWW-7VGA for DigitalWW. It works fine (when it works -> read on). I had to make some adjustments to the frame but this, I was expecting. However, I am having a problem that I can't seem to resolve. I would like you guys to give me a hint if you can.

I have plugged the monitor to an IBM T30 Thinkpad notebook. This notebook, like most of the notebooks out there, have the ability to power the internal LCD only, the external VGA monitor only or both at the same time. By default, when the notebook is on the docking station with the lid closed, it switches to the "external VGA monitor only" mode. When I plug a standard VGA monitor (Samsung Syncmaster 750s) to the notebook, I get an image. However, when I plug the DWW-7VGA, I get the following behavior : it looks like the signal is recognized as present since the green led lits up but the "on-screen display" is not showing what the resolution is, also no image is viewable on the display. When I switch the laptop to "both monitors on", I get an image on both monitor. I first thought it had to do with VESA DDC. I thought that the laptop was "asking" the monitor what was its capabilities and that the monitor was not responding. So I built myself a "DDC adapter" using the 24LC21A chip from Microchip (I'm an electrical enginneer). I made sure the adapter was working (using the samsung monitor and bypassing its DDC capability with my adapter, I got an image). So it doesn't look like the laptop is shutting down its hardware VGA drivers thinking no monitor is present like I first presumed. In fact, I have seen on the oscilloscope that the syncs are still there. Something must be different from "external only" to "both on" but I can't find what. I have installed the latest video driver from IBM.

So have you ever seen such a behavior and would you have a hint on what to do next ? I can't install the whole thing in my car before this is solved since I have no image when the laptop is in its docking station with the lid closed...

Thanks,
Guillaume