BACKGROUND
If you don't know what the Righteous 3D card is and what it can do, then go to the Orchid Technology website to find out. This board is an add-on to an existing VGA adapter, where the video signals from the VGA card are passed through the R3D card via a short cable. When the R3D is in use, the output to the monitor is switched by two relays on he card to the output of the R3D's 3DFx chips. One distinct advantage to this approach is that this high-end 3D card can be added to a system without sacrificing the existing 2D VGA adapter.
Unfortunately, with some VGA adapter - monitor combinations, the signal path through the passthrough cable and the R3D can adversely affect the high frequency response, which manifests itself as fuzzyness at higher resolutions. It seems that the bandwidth problem is a function of several variables, including the video card, monitor, resolution and user subjectivity. Many people have reported severe image degradation, while just as many don't seem to have a problem. I experienced only minor degradation, that I could live with, using my old video card/monitor setup at 1024 x 768 @ 70Hz, but when I upgraded to 1600 x 1200 @76Hz, windows text was simply unreadable.
This signal degradation problem has been discussed at great length on USENET, with a variety of solutions offered. Some have claimed to realize significant improvements by installation of ferrite beads on the VGA passthrough cable, but most have reported successfully overcoming this problem after bypassing the surface mount inductors on the RGB signal lines on each side of the switching relays. I have heard that these inductors are placed in the signal path to comply with FCC regulations regarding radio-frequency interference (RFI) (at least in the U.S.A.). Many people have bypassed these inductors by soldering tiny wires across them or have even removed them entirely. Since I really had no choice, I decided to try bypassing the inductors, but I was not willing to risk damaging the components on the board by soldering directly across them. I therefore traced the circutry and soldered the six jumpers onto the VGA connectors and the relay pins. This was much easier to do and facilitates removal of the modification. As others have reported, it was indeed the inductors that were responsible for the high frequency attenuation and after installing the jumpers, the signal degradation was gone.
PROCEDURE
First, make sure you have a problem worth correcting by such drastic measures. Compare the image quality with and without the R3D in the video signal path; you might find that it's a non-issue or at least tolerable. The most discernable difference will be in the sharpness of small text, e.g., the menu items in a window.
OK, if you find that you can't tolerate the signal quality through the R3D, then you still have a couple of alternatives left. If your monitor has both RGB and BNC inputs, you can connect the video card to the BNC inputs and the R3D to the RGB inputs and simply switch between the two inputs. Or, if you only use the R3D infrequently, you could manually switch the video cables each time you use it.
If you are still reading this, then I will assume that you have a severe signal degradation problem and input or cable switching is not a practical alternative. If you want to try jumpering the inductors, bear in mind that this will void your warranty. Remember, if you mess up the card, you are on your own and Orchid will not help you. So, make sure you are satisfied with the purchase before you attempt any modifications. I also will not be responsible for any subsequent damage or anything else that may or may not result from your modifiying or doing anything. All I am doing is passing along what I did and what worked for me.
The schematic shows where to connect the six wires. The red, blue and green wires
represent the red, green and blue signals, respectively. Using a small soldering
iron, carefully solder the six wires as shown to the solder pads on the back of the board
as shown in the schematic. (I used small insulated solid copper wire, the kind used
in telephone signal wire.) Be VERY careful to attach the jumpers exactly as shown
and not to bridge adjacent pins with excess solder or wire. There is a finite chance
that you could irreparably damage the board by shorting the wrong contacts.
Get a schematic that shows where
to attach the jumpers (R3dmod.gif, 720 x 480 x 256 color, 22K).
If you are not experienced with soldering techniques or reading schematics, I suggest you try to find someone who has the equipment and experience necessary. If you can't find anyone, then get the necessary equipment and practice a bit on an expendable circuit board until you are confident before touching your valuable R3D.
NOTE: The schematic was prepared from a Righteous 3D board revison "D" with the inductors L5 (blue), L6 (green) and L7 (red) on the VGA output connnector and with L7 (red), L8 (green) and L9 (blue) on the VGA input connector. If you have a board other than revision D, check to ensure that the connections are the same before attempting any modifications.
Wow! Is ANYONE still using these cards?
Click
HERE to send any comments or questions.
Created 11 August 1997
Last update 19 Feb 2007
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