Trying to Identify my Dodonpachi Board

Vexorg · Post by **Vexorg** » Mon May 25, 2009 8:48 am

When I bought my Dodonpachi board a couple of years ago, I assumed that it was a Japanese edition board, since it plays the Japanese version. Recently, I've begun to wonder if this is the case though, and although I am certain my board isn't a bootleg, I have begun to suspect that my board might actually be an International version with a burned Japanese version ROM on it.

The main reason I suspect this is because of the EEPROM on the top part of the board. Looking at the picture of an international version board found at world-of-acrades, it looks like there is a standard EPROM in that position as opposed to an EEPROM, leading me to suspect this was replaced. The other two EEPROMs on the board look like they're supposed to be there. It also seems odd that the EEPROM slot in question appears to be socketed, when it looks like this is not normally the case.

The board works and plays properly (as a Japan version,) but I suspect that something might still be off here. Any thoughts on this?

IronGiant · Post by **IronGiant** » Mon May 25, 2009 9:02 am

A few things first:

- the large 'EEPROM' which you're referring to (I assume you mean the large chip with the 'window' towards the top of the board) is in fact an EPROM.

- the 'window' on that chip should be covered with a suitable label/sticker - failing to do so means that, over a long period of time, the chip is more likely to be corrupted by UV light (UV light is used to erase EPROMs, but of course in very heavy doses)

The two smaller chips (also EPROMs) which you see with stickers are for the program code - this is the only EPROM/mask ROM code that differs between the International and Japanese version (according to the MAME code) and the large EPROM previously referred to contains some of the graphics.

In theory, it should be possible to program new EPROMs and replace the two that are labelled with the International versions - unless there is some form of protection on the board that prevents this.

So the only question that remains is this - why is an EPROM being used for some of the graphics? Well, the original mask ROM may have failed, or perhaps someone has been modifying some of the graphics (unlikely but possible).

Here's a pic of a board that has a mask ROM in place of the large EPROM on your board:

http://maws.mameworld.info/maws/img/pcb/ddonpach.png

So, in a nutshell, besides putting a label over the 'window' on that large EPROM I would personally leave things as they are.

Note: a mask ROM is read just like an EPROM, but it doesn't have a 'window' on the top and cannot be erased or even programmed by the user. It's manufactured with the internal silicon chip containing the data as specified by the customer. Some of the long, black chips on your board are mask ROMs.

A 'normal' EPROM (or UV-EPROM) requires Ultraviolet light to erase it.

An EEPROM is an electrically eraseable PROM.

http://en.wikipedia.org/wiki/Mask_rom

kernow · Post by **kernow** » Mon May 25, 2009 11:56 am

Its not got 'ATLUS' written on it like a JP board has. I think its an INT version with a JP rom just as you suspected.

robivy64 · Post by **robivy64** » Mon May 25, 2009 2:19 pm

Yep, not an original JP board.

And for some reason, one of the original MASK ROMs has been replaced with an EPROM.

rtw · Post by **rtw** » Wed May 27, 2009 2:04 pm

@Vexorg, what type of EPROM is mounted where there is supposed to be a MASK ROM ?

Post by **Dave_K.** » Wed May 27, 2009 3:04 pm

JPN region DoDonpachi

Vexorg · Post by **Vexorg** » Thu May 28, 2009 8:39 pm

Hmmm... Not sure what type of EPROM it is. There doesn't seem to be any sort of marking on it that I can see.

IronGiant · Post by **IronGiant** » Thu May 28, 2009 8:47 pm

Nothing at all? Any signs of it having been sanded/scraped off?

Vexorg · Post by **Vexorg** » Thu May 28, 2009 8:51 pm

Not that I can tell, but I'd need to take another look at it to be sure. 4I bought the board from a reputable source (Excellentcom) and it's clearly not a bootleg (aside from the EPROM in question everything looks legit for an international version board) so I don't think there's any intentional deception going on here. I suspect if I could probably come up with a correct version ROM to plug in, although I'm not sure if it would be necessary.

IronGiant · Post by **IronGiant** » Thu May 28, 2009 8:55 pm

I strongly suspect that it's simply been replaced because the original mask ROM failed. Please make sure that you put a label over the window on the EPROM though, to help prevent any data corruption.

rtw · Post by **rtw** » Fri May 29, 2009 6:47 am

@Vexorg, sometimes you have to read the markings at a certain angle due
to the way the text is printed.