Fat Agnus question

[cbmeeks]

Hello. I have an Amiga 500 motherboard that I bought a while back where the previous owner gutted it and sold off the components. I am in the process of trying to restore that board to a working computer.

I have found a Fat Agnus (8371) for a reasonable price. However, coming from Europe, I am concerned it's PAL only. Many of the Fat Agnus's I see listed on eBay have "(PAL)" next to the description.

I thought it was just the video chips that were PAL/NTSC in the Amiga and not other chips like Agnus and Paula.

Is this correct or does the Fat Agnus have PAL/NTSC versions?

Thanks.

[fastrobplus]

There are definitely PAL Agnuses, NTSC Agnuses and switchable PAL/NTSC ones. The 8571 is a PAL only Agnus. I don't know off the top of my head what this means for an NTSC motherboard.

[intric8]

Here is some detail on the variations of Agnus.

You don't have to worry about Paula et al.

[McTrinsic]

There are Kickstart-patches in Aminet on that will make an NTSC Agnus behave as a PAL- Agnus.

Maybe contact the author and ask for a patch the other way round?

It’s still maintained and very recently got an update to work with 3.2.2 ROMs.

[luvwagn]

Is there a patch that goes the other way, and makes a pal agnus ntsc?

[McTrinsic]

Please be aware that the Agnus stays an NTSC or PAL Agnus.

Can’t change the hardware.

Have a look at these programs, the might already address most issues when run e.g. in startup-sequence.

http://aminet.net/search?query=PAL+ntsc

[McTrinsic]

And here is the PAL patch.
Just get in contact with the author.

https://github.com/SirCathal/KickstartP ... r/releases

[luvwagn]

mctrinsic do you know what happens if you put a PAL Agnus into an NTSC Amiga via Rejuvenator? I bought 3 NTSC fat agnus chips (2MB), 3 PAL fat agnus chips (2MB), 1 PAL fat agnus chip (1MB), and 1 PAL fat agnus chip a/b (2MB) - ugh

[intric8]

If I remember correctly, the Rejuvenator in its original design only supports 2 Agnus chips. The 2MB Agnus is a very hard to find A3000 variety. The 1MB is much more common. If you put a 2MB Agnus in there that isn't the specific type, I imagine it simply won't work. This is why some folks are working to update the Rejuvenator code at some stage so that in the future different versions of the 2MB Agnus could be popped right in there. But by default, today, that is not the case.

That's always been my understanding at least.

[EzdineG]

mctrinsic do you know what happens if you put a PAL Agnus into an NTSC Amiga via Rejuvenator? I bought 3 NTSC fat agnus chips (2MB), 3 PAL fat agnus chips (2MB), 1 PAL fat agnus chip (1MB), and 1 PAL fat agnus chip a/b (2MB) - ugh

My Rejuvenated A1000 has a 2MB PAL Agnus via an adapter.

It just works as a PAL machine. There will be a slight timing difference created by the faster clock, but won't affect anything that I know of (maybe the ability to Genlock?)