Hard to explain, just singles lines of pixels that are glitching every now and again not across the whole row of pixels just parts, not on all games aswell
I get that every so often. I attribute it to the use of composite. In other news on this, if I leave my CD system at BIOS screen for too long, it starts to garble up. Doesn't hurt it, just looks like shit. Model 2 CD with BIOS revision 2.00 NTSC USA spec.
I thought so. Don't worry, it's not a glitch. Well, not a glitch as in a hardware fault, but as in a design oversight by Sega. It happens whenever the palette is updated (the row of pixels you see are the updated palette entries), and normally the values are written on the overscan area which you shouldn't see, except for PAL titles where the problem is much more notable. I recall someone mentioning that it's less notable on model 2s, but I can't confirm that, though it wouldn't surprise me as they unified most of the custom hardware to a single chip there (and further unified it later on).
I have a NTSC model 2 and it is very rare but I will get garbled pixels. It is more noticeable in hacked Sonic games than any other original Sega licensed title.
Notice on afterburner 2 about a 3rd down the screen now and again. This is on a VA6 model 1 PAL console by the way
The pixels you mention aways appear, regardless of the unit being NTSC or PAL. It's a hardware quirk from the Yamaha VDP chip design used and has nothing to do with SEGA. It probably was left alone because the chip was designed to drive CRT displays and 99.9% of the existing CRT displays at the time would crop that part of the image anyways.
Well these slight gfx pixel glitches aren't at the top or bottom of the 'active' display they are about a 3rd down the display. I'll hook my MD up to my capture device tonight and see if it shows it
Ok heres a clip grabbed on my iPhone of the gfx glitches im getting on After Burner II, im sure this doesnt happen usually????.... http://youtu.be/SCPHx9827pY
Looks like the glitches on my Cd system model 2 BIOS revision 2.00. Although mine are much worse. AFAIK these glitches were normal due to a mistake in the design of the Genesis. Am I right or wrong? Anyone who knows the hardware level a bit more care to explain what's going on?
That's not a glitch at all. It's what happens when a game tries to draw more sprites in the same line than the VDP can handle. Bits of all the sprites that are on the same line disappear. Also, the latency of the LCD display you are using don't help. There's nothing wrong with the system. Working as intended. Edit: And that's some neat, pristine image, btw. Great stuff
So it was Yamahas fault and not Segas? huh. The garbles are placed differently whether your system is PAL or NTSC though. At least that's what I recall, from when I was testing my md region switch. And yeah, sometimes they appear mid-frame instead of the bottom of it. Streets of Rage 2 does that too, on both of my model 1s (va5/6).
Cheers, i had to take a video of it with my camera phone as for some strange reason when i actually captured the game these 'gfx glitch's' didnt show up on the video! i did capture a Route A run on OutRun using the, Micomsoft SC-500N1 RGB Capture Card it is really rather good as it can capture @240p all for £88 bargin!!!.... http://www.youtube.com/watch?v=MMZE7f9u7aw
Keep in mind that the sprites will only disappear if they exceed a certain number of them in the same horizontal line. (not necessarily the exact same line, but sprites at neighboring lines will affect each other depending on their size). Also some games use several sprites to assembly complex objects. After Burner II is a very good game to observe that. Outrun not so good because there's a lot less elements at the screen at the same time. The Board that run both games on the arcade has only sprites, btw.
Well i could actually observe the glitches happening whilst play but when i watched the capture back there was none to see anywhere which is strange!?
the 50/60hz mod, i used the ground point from his new mod guide and the left hand side pad of JP3 from his old guide (not sure why he change to a new way of doing it as the new way is more difficult than the old 9=not connected (JPN) position 3 10=JP2 (Asia) position 4 1/ is wired as GND goes to common (we'll call this pin 1), pin 2 goes to JP2 (to get PAL), pin 3 is not connected (For USA), pin 4 goes to JP3 (For JPN) 2/ is wired as GND goes to pins 2 & 3, pin 1 goes to JP2 (position 1= PAL), position 2 is bridged to ground so no JP points are connected, so this makes USA, pin 4 goes to JP3 (position 3= JPN).
