DC VGA box problem...

[Minwah]

I just tried my old (but barely used) Dreamcast VGA box, as I want to hack it for my cabinet...but it doesn't seem to work properly.  The image is really yellow!  Everything looks clear, but as if it has a yellow overlay in front of it.

Does anyone know what could cause this?  I've tried wiggling the connector around in case it is a bad connection but it doesn't seem to make any difference.

I'm going to hack it anyway and see what happens on the arcade monitor (same thing I expect), but if anyone has any suggestions that'd be great

[Dave_K.]

Try it on a different monitor, or with a different Dreamcast (if possible).

[Minwah]

Try it on a different monitor, or with a different Dreamcast (if possible).

Different monitor does the same, and I don't have another DC but the output works fine with a Scart cable, so I guess it's OK.

I did the hack (cut pin 6) and it works on my arcade monitor...but as expected still yellow.  I think the blue signal is missing, but there seems to be continuity from the pin itself and the PCB, so I don't know what else to try really.  I guess it's just faulty, I'll probably get a new one.

[Dave_K.]

Could be anything really, but maybe take a look at the capacitor that couples the blue pin on the vga output port to the rest of the circuit.  Just trace backward from the vga output port of the vga box.

[Grasshopper]

As far as I'm aware the RGB signals simply pass through the VGA box without being altered in any way. Perhaps you could try connecting the blue signal from the Dreamcast direct to the monitor i.e. byepass the converter just for that signal.

[Dave_K.]

As far as I'm aware the RGB signals simply pass through the VGA box without being altered in any way. Perhaps you could try connecting the blue signal from the Dreamcast direct to the monitor i.e. byepass the converter just for that signal.

This is mostly true, except for the coupling capacitors which brighten up the picture just before the VGA port...could be that one cap for blue is bad or disconnected.

[Minwah]

Update....I said it the DC works fine with my Scart lead (it did last time I played Beats of Rage)....but now it doesn't    Rather than being all yellow, it is all black - I can make out the outlines of stuff though.  I tried the stock RF lead too, and I can't get that to work at all.

So it seems like the DC itself is dodgy.  I'm going to open it up and check the av port connections.  Is there anything else I could check?

[Dave_K.]

One of my DC's had the same issue with everything turning black (but you can see faint outlines of things.  The composite output from the VGA box still works, but the RGB/VGA doesn't anymore.  I think i fried the video chip because of a voltage surge from a RGB converter I was testing.

[Minwah]

One of my DC's had the same issue with everything turning black (but you can see faint outlines of things.  The composite output from the VGA box still works, but the RGB/VGA doesn't anymore.  I think i fried the video chip because of a voltage surge from a RGB converter I was testing.

Seems like the same problem...I just tried the composite out from the VGA box and it works fine, but still no RGB.  I don't know what happened to it, don't think I did anything I shouldn't have.

Maybe it got jealous of the GameCube & XBox sitting next to it 

[Rahzel]

Someone on this board a while ago said a lot of DC's got recalled because they had a bug where if you unplugged the controller while it was on a part of your DC would fry 

[Minwah]

Someone on this board a while ago said a lot of DC's got recalled because they had a bug where if you unplugged the controller while it was on a part of your DC would fry 

Don't think it was that as I haven't unplugged the joypad for ages...I'll remember not to do that with my next one tho, just bought one off ebay