PAL 600 XL at NTSC speed ?

[Level42]

Hey,

 

Just bought a nice 600XL in original condition (nothing changed inside). It's been my first ever computer so I wanted one again. Mind you I already own PAL 800, two 130 XEs, XEGS and a dead 800 XL. And ever since I bought that 600 XL I have always owned at least a couple of A8 machines.

 

I want to make this 600 my main machine though so I already found a lot of mods that I plan to do.

 

One thing I would like is to make it (switchable) to running at NTSC speed but keep the video out PAL. I will use a Sony PVM monitor and this can handle PAL and NTSC so it should be very flexible about the video signal.

 

I want to use chroma/luma output and would prefer to get rid of the modulator If possible.

 

The reason why I want it to run exactly at NTSC sped is because of playing the games at the correct speed for record points (and the feel).

 

Now I learned that NTSC machines have just 1 crystal and the PALs have two. Would it be enough to change the main system crystal to the one that is used in NTSC machines ? (And make it switchable, doesn't have to be able to change speed when on).

[Rybags]

Antic determines the 50 or 60 FPS rate - you can stick an NTSC Antic in and leave the rest and have an almost NTSC machine.

But the line rate will be slightly out so there might be problems with the display, e.g. black & white only or not steady.

 

Changing the main crystal for NTSC won't really work because there's a direct 5:4 relation between the colour clocking and pixel clocking for PAL and the machine by design caters for that. On the other hand, the clock rate difference between PAL/NTSC isn't very much and leaving it with the PAL one won't affect speed that much.

 

The second crystal as per PAL is used for colourburst and makes the video generation sufficiently different such that changing standards or making a machine able to do both isn't a trivial matter.

 

What I'd advise is just drop an NTSC Antic in for a try and see what you get on your monitor.

 

Another thing is GTIA has the register used for system identification so you'll still have the machine recognised as PAL by most software.

[Bryan]

The best choice is to get an NTSC/PAL capable monitor and have one machine of each type.

[Marius]

In 2600 land there is such a thing, which is called PAL60. Not in XL/XE?

 

I have mostly pal 50hz xl/xe and a few NTSC machines, and I love them both. If I was you I would keep the pal 600xl 'original'

[Level42]

For clarity: I am in the Netherlands so all my machines are in PAL. I have temporary borrowed a 800 NTSC machine from Mr.Atari and I succeeded in breaking the TwinGalaxies WR on Donkey Kong with it, but I can't keep that machine forever of course so if I would have at least one machine that would be great.

 

I think I've got an extra 130XE for trade if anyone in the US would be interested.

 

Yeah Brian I was thinking about something like that.PAL 60 As mentioned, I already have a Sony PVM monitor which can handle PAL, NTSC and the "fake" NTSC signal that comes from the later VHS recorders that were able to play NTSC material. These PVM monitors were used in broadcasting so I bet they are pretty flexible when it comes to syncing etc.

 

I have hacked a LYNX before with a crystal that made it run about 50% faster (switchable) and I realize that that is using a LCD display but I figured that the very minor clock difference between the NTSC and PAL 8 bit machines wouldn't be a problem. Haven't there been over clocking projects for 8 bit machines ?

 

Anyway Rybags' suggestion sounds easy enough, I don't think there have been any revisions of the ANTIC over the years right ? So I could use any NTSC ANTIC. However, I wonder if this will bring the games up to NTSC speed or just make the screen rate 60 Hz instead of 50?

I don't care so much for 60 Hz but the speed of the game must be correct.

[Level42]

Oh and since most games don't check for NTSC/PAL anyway I don't care if it will report that it is a PAL machine.

[Rybags]

PAL60 isn't an option. PAL60 is 312 lines at 60 Hz, the Antic you use gives you 262 lines at just under 60 FPS or 312 lines at just under 50 FPS.

 

There is a later Antic revision E - it's for 130XE and other systems running >64K RAM.

 

You could just drop in an Antic from an NTSC machine - the frame rate will almost exactly match real NTSC. Whether you get colour or just B&W will be another matter, all you can do is try.

 

The actual speed difference insofar as FPS will be unnoticable. Something in the order of 1/5th of a frame/second less.