1200XL PAL + Ultimate?

[+slx]

I just received a 1200XL and living in PAL-land I'm thinking about converting it to PAL. I read the instructions for the bitsofthepast GTIA adapter board and wonder whether the whole "changed OS" part of the conversion can be substituted by installing an Ultimate 1MB. If so, is it still necessary to install a 28-pin socket for the ROM adapter?

 

Is there a way to keep the "Atari Rainbow" screen and just patch the OS to work with PAL GTIA/ANTIC?

 

Anything else to get done while the machine is open? Do the various (easier) video mods work with the PAL conversion?

 

Happy Holidays!

 

 

 

 

 

 

[Rybags]

Fairly sure both the 1200XL OS revisions should work equally with PAL/NTSC just as the subsequent OS releases do, so the Atari rainbow would remain.

 

Ultimate 1 Meg gets access to the full address bus via connections to the existing OS socket and MMU. So I should think that the 1200XL should remain unmodified other than what's needed to work with it and a PAL conversion.

 

Video mods - that's sort of unexplored ground re 1200XL. I did an existing mod some time back for my 800XL and wasn't really happy with it, the RF and composite got washed out although the S-Video probably improved.

IMO what's good for NTSC isn't necessarily so for PAL, although stuff like removing parts of the RF/composite in order to remove cross-contamination of Y/C would be valid for both.

[+slx]

Thanks! Any ideas on why the installation guide for the mod says the ROM change is needed before the GTIA mod board can be installed?

 

[Rybags]

Main differences between Pal/NTSC OS are the key repeat rate and the determination of cassette bitrates.

 

After some discussion the opinion seems that the cassette system will tolerate the difference usually - in any case most of us don't use tapes anymore so it doesn't matter.

 

Key repeat - on XL/after the OS is generous in that the key delay/rate can be set by software anyway, so unlike 400/800 having the OS think we're running the wrong system doesn't matter as much in that regard.

 

The only reasoning I can see for ROM change on 1200XL is the confusing situation that arises if you run the GTIA for one TV type and the Antic for another.

The determining factor is Antic who decides if we have 50/312 or 60/262 frames/scanlines. But GTIA contains the register that most software will check if we have a Pal or NTSC system.

 

In the case where you run a PAL Antic but retain NTSC GTIA or other way round, you will infact need the OS change to reverse the behaviour. Possibly that is why it's included?

[flashjazzcat]

Don't know if this helps any, but it shows a 1200XL, PAL modified, with an Ultimate 1MB fitted:

 

 

Main thing to notice about the ROMs over on the left is that both OS ROM sockets were replaced with 28-pin precision sockets. Before Ultimate 1MB was installed, the OS ROM was in the top socket, and BASIC was in the lower socket. After U1MB was installed (fitted to the top socket), BASIC was removed, and note the jumper configuration just to the lower-right corner of the cartridge slot.

 

So: 2 x 28-pin sockets, jumpers as shown. To do the complete PAL mod, you'll need a PAL Antic, PAL GTIA (obviously), and a new master clock generator. The machine in the picture is driven off the VBXE oscillator.

[Frankie]

OMG! Look at all those goodies in that 1200xl !

[+rockdoc2010]

He's posted a selfie of his lewd hacker porn!