DC RGB modes (31, 15KHz, etc.)

Started by Endymion, March 23, 2004, 08:54:02 AM

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Endymion

Pardon the stream of consciousness that is to follow. If you care to skip it for nothing but a question proceed to the final paragraph. ;)

Okay so, some Dreamcast games/discs do 15KHz, others do VGA/31KHz--it would stand to reason that there are some out there which can do neither, seems Mortal Kombat Gold is one of them (and yes I love this game so shaddup) so I have to resort to the switch or cable-swap if I'm going to play them.

If it isn't obvious, I've gotten ahold of a "Performance" brand VGA box--it's the only one that I'm aware of which had a computer input pass-through, making the thing usable without disconnecting your computer, so as I'm setting up my DC to live more permanently aside my computer this has come a bit more to my attention. So far I've been able to master the cable swap method (boot with NO cable--after you hear the "beep" from the DC drive plug in the VGA box and it should work at 31KHz) but I don't like having to do this, not to mention I wonder if at some point in time I could have a zapped VGA box or DC on my hands. There is also the switch method, do the same as above, by swapping between the TV and VGA mode on the switchbox, but for some reason while I have managed to do that a few times on other cheaper VGA boxes, I haven't been able to get it on the Performance box. I don't know if this means it's not possible or if I don't have the timing down right. But whatever--

I seem to recall that one of the Dreamcast boot discs sold commercially, was it the DC-X? This is coming from deep in the recesses of my brain but I seem to recall reading somewhere (perhaps the good old Saturn-turned-Dreamcast list) that this boot disc or another like it had the ability to somehow set the RGB mode that the game booted with--is this the case or no, with either that boot disc (DC-X) or another similar (Utopia, et cetera). My Dreamcast is pristine, one of the first to roll out into the American stores. It still loads everything perfectly and with as much as I've read the bad karma reports from pirates and emulator fans alike it seems as if all have had trouble with their drives reading properly after playing around with burned CDs, so I'd like to avoid the Utopia type stuff if possible, but if there is a better method than the touch-and-go switch/cable-swap with the VGA box, it sure would make things easier in front of my VGA monitor.

Anyone?

benzaldehyde

#1
Back before I came to my senses and installed a modchip, I used the DC-X. It does let you cheat and set the mode... on some games. A few won't work at all (like Last Blade 2). Some have a messed up picture (like Jojo's Bizarre Adventure). Some worked well, but there was some terrible slowdown (like Gunbird 2). It works great for imports, but as for setting the scan rate, I'd have to say that it honestly sucks. I'd look about for an XRGB-2(+); those are great. But then, you'd just have to cable swap again. :( There are patches avaiable for burned games that allow VGA mode, but then you'd have the use of burned games about which to worry.

:ph34r: <Ducks super magic rocket launched across the water by Lawrence for bringing up burned games.>

Your cable swap, unfortunately, seems the best way. After the beep, you say. I've never tried it. Does it work well?

Endymion

#2
Yes, works perfectly, I have it down to a science, if I just get the cable in no later than one second after the beep, the 15KHz or TV-only mode games will boot VGA mode. I found when playing around with my 15KHz SCART, the same applied, although now that I think about it, I think I had to boot with the VGA box in VGA mode, then remove and swap with the SCART, that was the first time I ever managed to get Mortal Kombat to work in 15KHz/RGB. (Edit--there's a really funny thread in the old forum I started the day I discovered this. [Edit edit--Well I thought it was funny.])I guess I am not harming the box or DC but it's hard to shake this collector's paranoia. Even if I weren't skittish about doing it all the time, it is still a real PITA.

Games that work with this method do not always work "completely." Dino Crisis for instance, I think that was another game that didn't like either 15 or 31KHz RGB, and it was missing a lot of graphics--the 2D stuff before gameplay was glitched or just gone completely from the display. But evidently this is a problem with how the game was made, and subsequently never tested to work in either of these modes. The usual 2D-to-VGA mode blues (blocky Giga Wing stuff) of course also applies.

I guess I should keep trying the TV-to-VGA switch method to see if it works with the Performance box. But if not, I'll have no choice but to open the box up and try installing a second switch to use 15KHz RGB. I started to attempt this before but could not trace down the circuit, I am not sure if I don't know what to do with my tester (seems likely :unsure:  ) but the pins on it (tester) are pretty damn big and I could never get an isolated connect to the DC-side pins very well.

Edit #3: Who is that guy in your icon? Why does he look like Jerry Springer?

Endymion

QuoteBack before I came to my senses and installed a modchip, I used the DC-X. It does let you cheat and set the mode... on some games. A few won't work at all (like Last Blade 2). Some have a messed up picture (like Jojo's Bizarre Adventure). Some worked well, but there was some terrible slowdown (like Gunbird 2).
Grr, forgot to respond to this bit.

I haven't looked at JoJo in VGA but if it looks messed up, during gameplay that is, if by that you mean blocky well that's just the 2D problem that has always been an issue at VGA level, Guilty Gear X didn't have this problem because Sammy used higher resolutions interestingly. But if it's missing graphics then it could have a problem like Dino Crisis, which isn't creating overlays in that mode.

And you should try the cable swap, perhaps with a 15KHz SCART, on Last Blade 2, that could get it going, kind of like what I had to do to witness MKG in 15KHz/RGB (but in reverse).

benzaldehyde

In Jojo's, the screen is shifted up about 50%, then compressed into that space! A little frighteneing, really. (I fear that your collector's paranoia is a common syndrome. ;) ) I actually like the blockiness a little; at least the picture is sharp. :) I'll give it a shot; heck, the worst that can happen is the little thing'll explode. Oh, wait, that's actually pretty bad... :D

Endymion

Does anybody with a GameShark know how to use it to set the RGB mode, or the country lockout for that matter? I don't have the manual to mine anymore.

I've tried switching the Performance VGA adapter til I'm blue in the face, I think there is something different about its circuit that just does not work because I cannot for the life of me get it to override the mode setting without unplugging and replugging the cable. And I can't find a DC-X anywhere short of Lik Sang to buy. (Loathe to pay twenty bucks just to import a damn boot CD.)

Endymion

Ugh. Looks like I was already doing it right, which means I think I am going to wind up destroying the Performance box trying to mod it to do what I want.

I'll get a cheap box to practise a switch mod on first.