6 replies to this topic

[debugger]

Hi all

I'm just curious about a text file i readed somewhere, about converting a PAL Atari 7800 into a homebrew dev system. Considering that (afaik) the bigger base of Atari 7800 users have a NTSC system, why is this modification suited only for PAL consoles?

And why anyone would like to put an EPROM instead of the original console BIOS?

And the last question.... I don't have any NTSC 7800, mine is PAL, but i love NTSC I would like to convert one of my consoles to NTSC but i haven't found any information about this, maybe it's not possible?

Sorry for not pasting the URL, but i can't remember where i dowloaded the file

Debugger

[Thelen]

It's for a pal system because the creators of it are from a pal nation. The eprom is centainly needed, because there is some extra code added to the original BIOS. Used for functions to load your code or a rom image to the ram cart, or to read an existing cartridge.

Thelen

[CPUWIZ]

The homebrew dev-system you are talking about works on both PAL and NTSC machines. The reason why you would want to switch the BIOS is the fact that it will give you upload and download capability, regardless of wether your machine is PAL or NTSC.

As to your question about converting a PAL machine to NTSC, I can't help you there, perhaps some of the more hardcore 7800 guys could step in and help out. I would assume that it would involve more than simply changing the crystal on the motherboard.

[debugger]

Erm... guys what reply speed is this?

Mm nice to see the modification is suited for ntsc systems too, those are good news (and bad too because i'll have to buy two consoles, then)

By some reason or other i tought the upload worked in another way, maybe because the ones i use at work (not for atari, of course) work in a completely different way.

The reason to wanting to convert a PAL 7800 into NTSC is that i have more than one PAL consoles, but 0 NTSC ones

Thanks for the ultra fast responses..

[Thelen]

debugger said:

Erm... guys what reply speed is this?

Thanks for the ultra fast responses..

really quick ha !....I didn't even know it was for pal and ntsc.. But why do you need a pal and a ntsc system ?

Thelen

[debugger]

Well, for 3 reasons:

1: Because i'm not sure if i can play NTSC games on my PAL console, but in case i can, i'll play slower (at 50hz) and with black borders at top and bottom of the screen (because increased screen resolution in PAL).

2: Because the Atari 7800 was designed to be NTSC

3: Because if PAL games don't work on NTSC systems, maybe i can play the PAL versions i have but with correct resolution/speed

Debugger

[Mitch]

I don't have much information about coverting a PAL 7800 to NTSC either, but I'll tell you what I do know. I looked into this a while ago after I noticed that one of my PAL consoles had PAL/NTSC jumpers on the motherboard. I was never able to successfully convert it but if you want to go for it, here are some tips. Besides the crystal you will need to swap out the TIA and MARIA chips with NTSC versions. Check in the 7800 archive section here at AtariAge, there are some nice schematics for the 7800 in both PAL and NTSC formats. Check them for differences.
Good luck.

Mitch
http://atari7800.atari.org