Knuckles Chaotix sucks

[Chibisteven]

I have a Genesis Model 2 and this game doesn't work. Never has. For years I figured my 32X was broken. I bought one other game Cosmic Carnage ages ago but still never played it. I just assumed I had a broken 32X and never got around to replace it. So I passed up on Tempo when it was 10 bucks all the time. Now it's over 100 CIB. It was not until an episode of James and Mike Mondays where they had the game crash at the exact moment mine did. I was shocked. They kept trying different things then finally using a Genesis Model 1 is what got it to work. So all these years it wasn't my 32X or the game but some dumbass oversight by SEGA. I am still bitter about this.

The freezing issues I had with my model 2 VA2.3 with the 32X and Knuckles Chaotix were a lot at first (froze at the SEGA logo, than the title screen) but as the console warmed up with me playing regular Genesis games which didn't freeze and than trying Choatix again the issues went away slowly and the game was more and more playable. I have all sorts of hardware issues with that Genesis as it had a long and very abused life given all the crap that ended up happening to it, I'm surprised it even turns on and reads cartridges at this point. SEGA CDs won't even work if you connect it to the expansion port, found that out yesterday.

By construction aspects alone, a model 2 Genesis should be more reliable but it appears that like the audio circuits they also managed to goof up digital logical circuits in some revisions. I guess cost reduce here should mean lots and lots of cut corners. That said it looks like those issues are mostly fixable.

On an unrelated note as I mentioned this a little bit earlier in this thread is that I got the tray in my Sega CD model 1 to actually stay open and it seems to be reading games flawlessly now, regardless if it's burned disc or an original copy. I need new capacitors for the SEGA CD as the Genesis audio when ran through the SEGA CD is distorted. Looks great with my fully recapped model 1 VA3. Most of the work has gone into model 1 hardware restoration and maintenance. My other Genesis consoles are more after-thoughts at the moment.

[Eep386]

Anymore I always put an 18pF cap at C13 on every single VA2.3 I come across, regardless if the CPU is made by Hitachi or Motorola. 18pFs caps are cheap, VA2.3s not so much.

Not sure if cleaning up the 68K CLK will fix flaky 32X issues, but it surely won't hurt things any. I know the VA1 32X isn't supposed to need that terminator on the Sega CD connector, but have you tried putting one on there and seeing if that changes anything?

What can also cause symptoms to improve as the system warms up is a faulty/flaky 7805 regulator, though that's a little less likely than a noisy CLK or, indeed, a bum cap somewhere. Though the cap would have to be a critical one that's grossly defective to bring the whole system crashing down, as Sega CS did, to my astonishment, place redundant 5V DC smoothing caps all over the board. (Hence why I don't really think recapping the Genesis will magically make the 32X work any better with it.)

[Chibisteven]

Anymore I always put an 18pF cap at C13 on every single VA2.3 I come across, regardless if the CPU is made by Hitachi or Motorola. 18pFs caps are cheap, VA2.3s not so much.

Not sure if cleaning up the 68K CLK will fix flaky 32X issues, but it surely won't hurt things any. I know the VA1 32X isn't supposed to need that terminator on the Sega CD connector, but have you tried putting one on there and seeing if that changes anything?

What can also cause symptoms to improve as the system warms up is a faulty/flaky 7805 regulator, though that's a little less likely than a noisy CLK or, indeed, a bum cap somewhere. Though the cap would have to be a critical one that's grossly defective to bring the whole system crashing down, as Sega CS did, to my astonishment, place redundant 5V DC smoothing caps all over the board. (Hence why I don't really think recapping the Genesis will magically make the 32X work any better with it.)

I've tried the terminator on the Sega CD connector long before I had an actual SEGA CD and the machine didn't act different with the 32X attached. When I finally got a SEGA CD and tried connecting it to the Genesis VA2.3 it wouldn't boot and this combo was a simple model 2 Genesis and model 1 Sega CD with no 32X combo. I don't have a model 2 SEGA CD on hand but the model 1 SEGA CD works with the model 2 VA1 and VA1.8 that I have just fine. I've tried cleaning the connector ports on both and the VA2.3 Genesis just won't work.

My 32X is VA0.

[Eep386]

Hm... where did you get this VA2.3 again?

Just to eliminate one possible mode of failure, do the colors shift/change onscreen as the system warms up? Or does it ever randomly lose sync? (trying to rule out a flaky/aging 53.6931 MHz main crystal)

Coincidentally my 32X is a VA0 as well. I always use the terminator when I play on it (which isn't that often anymore sadly).

[Chibisteven]

Hm... where did you get this VA2.3 again?

Just to eliminate one possible mode of failure, do the colors shift/change onscreen as the system warms up? Or does it ever randomly lose sync? (trying to rule out a flaky/aging 53.6931 MHz main crystal)

Coincidentally my 32X is a VA0 as well. I always use the terminator when I play on it (which isn't that often anymore sadly).

I had my Genesis model 2 VA2.3 since Christmas of 1995. The shell is held together by one screw and the metal EMI shield is held together by 5 (one in each corner), the reset bottom is broken and the red LED is gone. I did not take good care of my Genesis consoles when I was younger and my brother was the same way towards it. Fried a few of them back in the early 90's and my parents kept buying more. It's the Genesis that barely survived against all the odds against it and it truly was the last one my parents were actually willing to buy me and my brother at that point. Nowadays I treat my consoles a lot better and most of them work like new with zero problems and look brand new.

The color is always stable and nothing never loses sync.

[Blades]

Never had issues with Chaotix on my VA6 Genesis and VA0 32X.

The special stages are a challenge indeed.

[Chibisteven]

I never had a problem with my VA0 32X and my VA3 model 1 Genesis other than my VA3 model 1 runs a little hotter than I like it to when a 32X is attached but that's the same with pretty much every Genesis I put this mushroom in. LOL

The only take away from this thread so far is that the VA2.3 model 2 Genesis that I own should be considered mostly unreliable for any serious testing as far as I can tell. I can't tell which issues were caused by me other than the broken LED and reset button and which ones are all SEGA's fault with this revision because it always performed better when it was warm with games like Streets of Rage (missing DAC samples when the machine was cold) but with 99% of the games I played on it, I couldn't even tell at all. So far the ones that are clearly SEGA's fault are the main 68K processor getting noisy signals and being I never owned or played a game that made this obvious I would of never known about it. Then there's that hosed up sound circuit for which I blame myself for constantly as a teenager all the way into adulthood until I finally knew the truth about why there's partially missing PSG in games. It's why I don't bother myself with it anymore.

Instead of saying Chaotix sucks, what would be most helpful is finding out which board revisions are the most flaky with the game in general and the condition of the said machines that are flaky.

[Eep386]

As I mentioned before, VA2.3s with the 315-5786 ASICs require an 18pF cap on C13 in order to be stable.
The blame lies at the feet of Sega CS for leaving this cap off.

This ASIC despite its sensitivity to CLK noise is ironically the better of the two ASICs you'll find on VA2.3 consoles, as that seems to be its one major defect (and thankfully one often easily fixed). The alternative ASIC, 315-5685, has a silicon snafu that makes shadows/highlights kick in one pixel too 'late', and often has trouble rendering the left side of the screen when processing heavy raster effects. This little goof-up is likely Toshiba's doing. What's funny is, not all 315-5685s will have defective left-side raster effects, perhaps Toshiba was quietly slipping some quick fixes into the chips as production wore on.


(notice the light blue lines that flicker at the extreme left of the screen in the wavy Sega logo background on the pic - crappy camera doesn't pick it up that well sadly)

Regardless of the ASIC though, all VA2 and VA2.3 will have broken/quiet PSG due to Sega CS again being numskulls and using a voltage divider to mix in the PSG, instead of doing it the right way and simply using a much lower ohm-value pulldown resistor.