Fabrice,
On Sun, Jan 10, 2010 at 7:56 PM, Fabrice GIRARDOT <f4brice@gmail.com> wrote:
>
> I'll be interested in this information.
> William said it may be a bootleg by SEGA, but it would be surprising.
> I may post this connector pinout if needed, if you want to compare it
> to Rockola.
I would definitely post the pinout. It could help someone out in the future.
If it's ascii, you can post it to the list as new thread, where it will be
archived and searchable via google. It's also good timing, as I can add it
to a board I'm laying out.
It's more likely Sega licensed it. Most people who bootleg, don't put their
name all over the place.
This afternoon, while checking signals on RAMs, then "K" bus, then N2,
> I discovered that there is a problem for sure on bit K1, maybe K3 and
> K10 also. Either N2 (74LS257) is broken, either some chips set K1 to high.
> Since it's currently 03:00 in the morning in France, I'll continue
> checks tomorrow evening. ;-)
RAM faults more typically manifest themselves on the W bus.
In your favor, being stuck is much better than having the wrong data.
Hopefully you'll get lucky with the accumulator selector. Good luck!
>
> At 2uS/div, your DSO may not be sampling fast enough to catch the complete
>> transition to the opposite logic state, before the next transition begins.
>> Remember, you're looking at the inside of a 5MHz CPU. Try 50ns/div or better
>> and see how it looks.
>>
>
> I already tried at 200 ns/div.
> Here is it : http://aquafab.free.fr/gamoover/all.png
> My Fluke DSO goes as fast as 5 ns/div, but it's hard to catch the
> exact interresting instant.
>
>
You probably wouldn't see them at 200ns/div, as they're on 200ns centers, a
byproduct of 5MHz I imagine. At 5ns, you probably wouldn't have enough
buffer memory to see what you're looking for. Sometimes analog is still
better than digital...
> FWIW, I've never seen a prom in a CCPU that didn't work, but did have valid
> contents. Therefore, if you validate contents, the probability is very high
> that the device is good. Further, PROM failures on the CCPU do happen, but
> are statistically very rare.
>
That's interesting.
> Of course it's not 100% sure, but I'll trust your experience.
> What about RAM failures ? SEGA is using NEC 牌D2101AL-2 chips.
>
>
The RAMs suck. I guess they're better than core, but than again, core is
more reliable.
I've seen all brands fail. I made custom hardware to test them in circuit,
otherwise it can be tricky. Again, issues on the W bus are 99.9% ram, but K
bus issues can get much more complicated. I would advise not working K bus
issues after midnight...
Hope that answers some of your questions.
>
Yes, merci beaucoup. :-)
>
>
de rien!
>
> P.P.S. Is your control panel missing buttons? Space Wars has 10 buttons,
>> used to start the game. I see them on the game flyer, but not in the picture
>> of your actual game.
>>
>
> Yes and no.
>
> <snip>
> There is no "hyperspace" button, no game choice button...
> But, when I look from inside the cabinet, I can see a lot of square
> holes in the english panel, which are covered by the top panel...
>
>
Hum, that's lame. You might want to fix that if you can find the right
buttons.
> I'll take some pictures of this.
>
> The game PCB has all the required inputs to handle all Space Wars
> buttons, but most of the "choice" buttons are not available.
>
>
> Regards.
>
> Fab
>
bon nuit,
-Mark
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Received on Sun Jan 10 22:23:06 2010
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