List of A500 mobo revisions and appropriate chips?

[Photon]

Yes, this is what logic dictated. So Agnus "unlocks" ECS for the other chips - if by ECS all you want is to address more chipmem.

As for slowmem, I was only talking about hardware incompatibilities. I just didn't see how it would be impossible to have more than 512k chip and slowmem at the same time, since both types of memory was supported before and there's just more of it.

Originally Posted by hooverphonique

Where in the memory space the trapdoor expansion ends up is configured by motherboard jumpers - it isn't affected by agnus revision (but you still need a 8372a for 1MB chip, of course).

So on A500+ mobos (and maybe Rev8 A500 mobo), there are jumpers to fix it. And possibly on a mobo with 1MB chip slots, you could stack chips for 2MB chip with 8372B, and still set trapdoor mem to slowmem.

Don't mind me, just thinking out loud But IDK, might have been simpler to just "also" support 1MB chip. Maybe it was a was to shift modding to stores and customers, to not have to make too many changes to the revisions?

[hooverphonique]

Originally Posted by Photon

So on A500+ mobos (and maybe Rev8 A500 mobo), there are jumpers to fix it.

On the rev 8 there has to be jumpers to switch between 512kB/512kB and 1MB since it's used for both A500 and A500+ - I think you need a trapdoor expansion for the 512kB slowfast though (rendering half the mobo ram inactive).


The rev 6a has jumpers so you can switch between 512kB/512kB and 1MB, but only has 512kB on the mobo out of the box - it can be populated with 4 extra ram chips for 1MB onboard chip though.



Disclaimer: The above is without using any third-party Gary adapters, etc.

[4pLaY]

Originally Posted by Jope

Here's pictures I was sent by someone. Perhaps 4play? http://jope.fi/amiga/a500rev7/

Those pictures did not come from me. If anyone is interested enough, i can pull mine out and try and do some more/better pictures.

[AmigaHope]

Originally Posted by Jope

Super Denise's reason to exist is that it supports higher horizontal frequencies than 15kHz. So if you're happy with PAL/NTSC (everyone running ECS should accept this fate), a regular Denise can be used even with a 2MB Agnus just fine.

The higher horizontal frequencies let you do fun high-quality Paula audio (especially if you fix the permanent LPF), so there is more value in them than just displaying stuff.

Also they support 35ns pixel clocks on 15Khz screens so you can do some stupidly high resolution text displays if your monitor has a high enough dot pitch. It also lets you do some crazy NTSC artifacting color effects, giving you great control over your fake chroma waveform, letting you display an image with way more colors than HAM on a composite display.

[Jope]

Any other ECS machine than the A3000 becomes intolerably slow at these higher refresh rates, unless you have RTG. That's why i was talking about accepting the 15kHz fate. :-)

[utri007]

I have Rev 7 A500 with 8272 Agnus and KS2.0, I have no idee is this original configuration.

Are these rev 7 boards rare?

[zipper]

Yes.

[Jope]

Cool that there is one in Finland too. Not many out there.

[utri007]

Here :

https://1drv.ms/u/s!AsdbQ2CKZfHPhLh5y82Gk2w3_Zp8aA

It has some differences to other. This one has a small daughter board.

[Jope]

That board was sometimes seen in rev 6 boards too.. Seems they had a chip shortage back then.

[Oli1974]

I wonder what Rev 1 and 2 would have looked like.

[Pyromania]

What’s the very best Amiga 500 motherboard. I regret selling my custom cameo painted A500 in 1993 and am on the hunt for another one for the sake of nostalgia. I’ll add a Vampire V4 card to it once I find one I like. I’m the recent happy owner of a 060 based A1200 from a very nice gentleman named Steve on AmiBay. That will also get a nice V4 card soon but I don’t know what I’ll do with the 060 card, maybe get another A1200, lol. I should have never sold any of my Amigas including two Amiga 4000T machines. Well I actually gave one away as a gift, lol. Those are so expensive and valuable now since very few were made compared to millions of A500 machines that were sold. I was a proud owner of the Amiga 500 for many years and I got me started in my very first IT job. Selling and supporting the Amiga for Commodore Philippines.

[Jope]

Rev 6 and rev 8 are the ones to go for, depending on whether you want 1MB or 2MB of Chip RAM.

2MB of Chip with rev 6 is of course also doable with a megachip style board in the Agnus socket.