Convert a PAL XE to NTSC?

[+Larry]

I've seen several threads that discuss getting PAL software to run on an NTSC machine, but is it possible to *convert* a PAL machine to NTSC so that it is fully operational?

 

Or-- does anyone in NTSC-land have a PAL machine, and what kinds of issues do they have with software, monitors, etc.

 

Has anyone been down this road before...

 

-Larry

[Rybags]

The main question would be: why?

 

About the only benefit would be games running at their intended speed (well, American originals, anyway).

 

Apparently, a lot of A/V freaks in the US liked to run a hybrid mode "PAL60" although that is PAL resolution combined with NTSC refresh rate.

 

If you converted a machine, it would be a NTSC resolution, PAL type signal, and the refresh rate would probably be somewhere around 59.54

 

If you have a reasonably modern TV it should handle a slightly off-spec signal OK. I've created custom graphics modes using the nVidia control panel, and PAL60 worked fine on my TV, as did modes with refresh rates slightly over 60.

Edited September 8, 2007 by Rybags

[+Larry]

The main question would be: why?

 

About the only benefit would be games running at their intended speed (well, American originals, anyway).

 

Apparently, a lot of A/V freaks in the US liked to run a hybrid mode "PAL60" although that is PAL resolution combined with NTSC refresh rate.

 

If you converted a machine, it would be a NTSC resolution, PAL type signal, and the refresh rate would probably be somewhere around 59.54

 

If you have a reasonably modern TV it should handle a slightly off-spec signal OK. I've created custom graphics modes using the nVidia control panel, and PAL60 worked fine on my TV, as did modes with refresh rates slightly over 60.

 

Hi Rybags-

 

Why? -- I may have several PAL machines on my hands, and I would want them to function in the NTSC environment.

 

Any ideas on the conversion details -- maybe "plug and pray?"

 

-Larry

[Rybags]

Details - unsure.

 

There's threads around about doing PAL conversions on NTSC machines, so it would probably be a near identical process.

[+Larry]

OK -- in researching this topic, I run across PAL-I and PAL-B which have slightly different characteristics. Is this significant to the Atari, or are they essentially all alike?

 

So far, looks like to do a full conversion, I need to replace GTIA, ANTIC, two oscillators, and the OS Rom. (I just love desoldering those 40-pin IC's, but I'm a lot better at it than I used to be.) To do a partial conversion, something less.

 

Looks like an interesting project.

 

-Larry

[Rybags]

Most of the PAL standards are very similar. The main difference is with the seperation between the audio and video frequency carriers.

 

That is only relevant if using RF - your best bet would be A/V or S-Video anyway (through the monitor port).

 

Actually, come to think of it, the PAL -> NTSC conversion might be more difficult since NTSC Ataris run off the one crystal where PAL ones need a second one to generate the correct colour carrier.

 

You can also get away with using a NTSC GTIA with a converted to PAL machine - no idea if that works the other way too.

 

IMO - too much effort for little gain. If anything, there is a great demand for PAL machines in the US due to most software (ie demo) incompatibilities lying with NTSC systems.

 

As such, you could probably easily negotiate a direct swap with someone, rather than risking bricking a perfectly good Atari.

[+Larry]

Most of the PAL standards are very similar. The main difference is with the seperation between the audio and video frequency carriers.

 

That is only relevant if using RF - your best bet would be A/V or S-Video anyway (through the monitor port).

 

Actually, come to think of it, the PAL -> NTSC conversion might be more difficult since NTSC Ataris run off the one crystal where PAL ones need a second one to generate the correct colour carrier.

 

You can also get away with using a NTSC GTIA with a converted to PAL machine - no idea if that works the other way too.

 

IMO - too much effort for little gain. If anything, there is a great demand for PAL machines in the US due to most software (ie demo) incompatibilities lying with NTSC systems.

 

As such, you could probably easily negotiate a direct swap with someone, rather than risking bricking a perfectly good Atari.

 

That's a good point, but I look at this as an experiment. Once I socket Antic and GTIA, I can find out to what degree these are internally compatible. I certainly don't expect the "patient" to die, but I'll ask for volunteers...

 

-Larry

Edited September 9, 2007 by Larry