Picture appears black and white using J-PAC and ArcadeVGA

[patrickmaher]

I got a JAMMA cabinet with a working arcade monitor last weekend. A few weeks back when I checked it out at the sellers location I saw it running a JAMMA PCB with colors that looked fine. I don't have a JAMMA PCB to test with.

I set up the computer with the ArcadeVGA and the J-PAC attached to the JAMMA harness. I boot up the computer and I get the video from the computer displayed on the arcade monitor but it is only black and white. Everything including POST, the Win 98 logo screen, and games in MAME are all black and white. The 3 J-PAC lights are on indicating that everything is working.

When I set the windows desktop to blue it looks black.

I noticed that what seems like the white in "black and white" looked a little bit blue. I tried changing the RGB bias and gain on the monitor and I can get an even grayscale color(looks completely black and white with not slight blue tint). When I try to work from there to get correct colors by changing the RGB gain and bias I cannot get colors that look correct. I can see the display tint red, green, and blue when I turn the respective dials.

I tried the nokia monitor test from the files section on retroblast and I tried to tune the monitor color settings to get the color setup correctly. I can turn up blue and get stuff that should be blue looking blue, but if I then try to adjust red to get proper colors for red bars I can not get correct colors. I'm new at using arcade monitors so I don't really know what I am doing and it is hard to get my head around what I should see when I change the color settings on the monitor, it's hard to tell what's happening because I don't know what to expect from a working system. I feel like when I even out the colors and see grayscale, I should actually be seeing a correct color image. the intensity of each color should be the same on the monitor side and the computer should tell the monitor what combination of colors to use to produce a certain color on screen, correct?

It seems like the monitor is not getting the correct colors sent from the computer.

Has anyone seen a problem like this? Is there any tests I should try to determine what is happening? Do you think it could be a problem with the ArcadeVGA or J-PAC?

I did contact Andy at Ultimarc and he mentioned a problem with the J-PAC could cause a loss of one or two colors but I don't think that he thinks it is related since I am seeing black and white and not a lack of 1-2 colors. Although maybe I get black and white with a certain RGB gain and bias and when I mess with it I get wrong colors because some colors are missing?

I also started to notice the top left corner of the screen is discolored from the rest of the screen. When I change the RGB bias and gain I can notice this more. Does this mean the monitor needs to be degaussed?

Thanks,
Patrick

[Popcorrin]

Contact Ultimarc.  They had some faulty resistors in a recent batch of jpacs.  Andy will take care of you.

[patrickmaher]

Thanks for your info.

I did contact Andy at Ultimarc and he mentioned the problem with the resistors that you are talking about. He said it would cause a loss of 1 or 2 colors and not a black and white image, so I do not think he thinks the problems are related.

What do you guys think? Could this be a loss of 1 or 2 colors that is causing my problem?

Any other suggestions if this is not the case?


Thanks for you help

[patrickmaher]

I have attached some pictures I took earlier this week with a digital camera I borrowed from a friend.

The first 2 pictures show the win logo and desktop with the black and white look. It does look slightly blue.

I also took a picture of the energy star logo that shows during POST on the arcade monitor, then I put a regular video card on the computer and hooked it up to an lcd computer monitor and took a pic of how it should look with color.


I started to mess with the RGB gain and bias, if I turn the dials all the way to the left for R, G, and B gain I see everything in sort of a grayscale. If I turn all the gain dials all the way to the right then I see everything with just black and white, no in between gray colors.

I tried chaning the color settings while looking at the energy star logo on the POST screen. In the arcade monitor picture I posted you can't even see the half circle globe, but if I turn up the green gain I see the globe start to appear in a green tint (by turning up I mean turning the dial to the right because that seems to turn the color up).

I tried displaying 3 bitmap images in paint. One Red, one green, one blue. Each looks the same on the greyscale screen, all show up as a drak grey. No matter which of the 3 bitmaps I display I seem to see the same display. If I turn up the red gain the bitmaps look bluish green. Turn up green they look purple. If I turn up blue they look dark green.

Please help me. I am getting really frustrated with this. Has anyone seen an arcade monitor do this before? Am I just really bad at tuning the color settings?

I really don't want to bother Andy at Ultimarc any further if this is actually a problem with my arcade monitor.

What do you think?


Thanks

[AndyWarne]

I already sent a replacement board on 24th. The red color is missing here. The resisror module at location R8 is the problem. We have had these in the past few days dropping like the proverbial flies. It's rare these days to get this type of batch problem with electronic components and it's the first time we have had this happen but it has certainly hit us!
Needless to say we have switched to a different maunfacturer now!