Home Page Forums MAME MAME GO-NET Mega Drive (SEGA MegaModem)

Simple solution: Just dump it and leave it at that. Given that the cart has no modem hardware inside it at all, it should not be anything bizarre going on beyond what usually is in a cart.

If you have the ability and will to get it X-rayed of course, then doing it is fine.

LN

Maybe I'm an ignoramus, but isn't getting it dumped much more important than getting the innards documented? I mean, in 30 years the ROMs will probably be blank/erroneous, but the actual PCB, chip labels and so on will probably be fine and can totally be documented from even a broken cart.

Depends. A straight dump from the edge connector may not actually dump everything in the cart if it uses an odd banking or overlay scheme that your cart reader didn't identify. Then there are weird carts where they've applied patches over particular address ranges with additional chips that you could never properly dump at the edge connector.

What this gentleman says. In other words, there's no saying your dump is good or bad without looking at the hardware. I stand by my point which is that dump is not meaning much by itself. In my eyes there's no half-preservation, just like there's no half-logic, you preserve it or you don't, and in this case you don't.

Regardless, I want to reiterate that a clear hi-res scan of the modem's PCB (one with readable chip labels) is the most important thing now for emulating it.

I think I have that, I'll post if I find it.

I asked my boss - my own Fraunhofer institute does not have an X-ray machine. However there are two more Fraunhofer institutes nearby that *might* have one. Problem would be to convince them to scan the cart for you. Also the university is close - will ask at their physics department.

The best option would be a luggage scanner used at airports. I'm quite surprised by the quality of PCBs detected inside laptops, mobile phones and similar devices. I believe it would be enough to guess what is inside the game.

There's a guy on the Dumping Union list who has access to an X-ray scanner and would be willing to scan it for you if you can send it to him, he is in Norway I believe.

The thing you have to understand is (according to him) that if there is an EPROM or EEPROM inside the cartridge, it could very well be erased during a decent X-ray scan. I'm not sure you would want that...

I already thought about that when the idea was brought up but I forgot to consider this when looing for a way to do the scan. Thank you for the warning. No, I wouldn't want to take the risk no matter how small.

So I think I'll leave it like that. There is no urgent indication there is missing anything except for a proper emulation of the Modem hardware anyway. We'll see when this is finally becoming a reality.

However - can't you just judge the cart type from the game serial? According to http://www.arcade-gear.com/Games/Sega/Sega_Mega_Drive.htm G-45 releases are battery type one, G-55 battery type 2 and special carts like Virtua Racing appear to use different serials. G-45 is shared by different games for the Mega Modem too.

^ Definitely not, that's just a catalog product ID and certainly can not reflect all the complexity of its hardware. Here's an example of a MD cart pcb, you'll see for yourself it can be quite stuffed.

http://img38.imageshack.us/img38/521/gamefactorypcb.jpg

as Vaas mentioned, your dump might be incomplete because of some unusual layout not supported by your retrode, I have seen that case, and you could easily have dumped just a portion of the rom(s) then. the retrode is making it look easy but there was a lot of engineering work behind that and Matthias (was it?) did not implement pcb layouts he never heard about.

I'm not sure I entirely get the label problem, can't you remove the sticker with vapor, then re-stick it with some paste?

Whatever, full preservation can sometimes mean you have to sacrifice something, I know about that having sacrificed a lot myself, you may want to keep that in mind before buying insanely expensive carts, though I know you think you're doing it for greater good, but perhaps you should let it to people with stronger resolve and stick to the more mainstream material.