A2000A / Rev4

[LimpingNinja]

Hey Everyone,

I recently acquired one of these Rev4 and in looking for information found some decent details: http://theamigamuseum.com/amiga-models/amiga-2000-a/

Though most forum posts have titles like "Found the dreaded Rev4" or comments like "I had this machine... it was dire". Interspersed between those are people fond of it as a collectible.

I sit on neither end of those spectrums, I own a Vampire V2+ that I will be plugging into it. From all research it seems like this will work within the A2000A and should alleviate some of the concerns with the board itself anyways.

Does anyone have additional objective information on this being a "bad idea(tm)" or what kind of major funk may occur?

I sent a message to the maker of this video, and his response is below:
[ Show youtube player ]

I have a 1986 rev4 A2000 and I ran the vampire 2 in it for a while and to be honest I had zero problems . The only reason I changed to a rev 6 was that I needed a full video slot for the toaster. I have another rev6 and 6.1 also which again ran the vampire perfectly well. Most of the revisions were because of RAM upgrades , kickstart and cpu differences from non Motorola fabs. Buffers and resistor packs were added and then removed to suit. My advice is to try it and get the chip ram to 2mb and have some fun. What’s the worst that can happen ?

Second note is where would I find a compatible board to get the chip ram to 2mb from the measly 512kb (I also thought it would only get up to 1mb with the ram card?

-LN

[Jope]

It will be rather difficult to upgrade the A2000A past 512kB of Chip, as it has the old skinny Agnus.

You would have to design a new PCB that carries a fatter Agnus and the additional RAM.

[LimpingNinja]

Originally Posted by Jope

It will be rather difficult to upgrade the A2000A past 512kB of Chip, as it has the old skinny Agnus.

You would have to design a new PCB that carries a fatter Agnus and the additional RAM.

I’ve read a few people upgrading the chip ram with mods, but it seems like the approach here is to upgrade via the MMU slot:

“1024K (512 KB chip onboard + 512 KB fast on MMU card)
– MMU card supports another 512 KB of RAM, which can serve as either fast RAM or for Kickstart MapROM function.”

What’s the difference here, is the MMU less preferred access? Supposedly it maps to the “slow ram” registers (link in first post).

..... but another question would be whether that 512kb even matters for anything with the Vampire card in?

-LN

[Jope]

Mm, as you quoted yourself, the CPU slot card does not show up as Chip RAM, it is true Fast in the C00000 range, not Slow RAM like in the A500.

You said you wanted 2MB of Chip RAM, which is not a trivial mod for an A2000A.

If you intend to install a Vampire, the CPU slot card is totally unnecessary, as the Vampire has all the Fast RAM you need.

[LimpingNinja]

Originally Posted by Jope

Mm, as you quoted yourself, the CPU slot card does not show up as Chip RAM, it is true Fast in the C00000 range, not Slow RAM like in the A500.

You said you wanted 2MB of Chip RAM, which is not a trivial mod for an A2000A.

If you intend to install a Vampire, the CPU slot card is totally unnecessary, as the Vampire has all the Fast RAM you need.

Sorry maybe there was confusion in how I wrote it.

I'm asking questions not specifying my desire. I've little knowledge of the hardware configuration details so am asking in order to gain it. I didn't say I wanted anything, I asked where I would find a 2MB MMU card (and mistakenly correlated it to chip ram); because from what I understand they were only made in 512kb for the A2000A.

That isn't my main question anyways; so for clarity, to remove confusion:

1) Does the 512kb of Chip Ram even matter with the Vampire?
2) Will having such low Chip Ram cause any issues down the road?

-LN

[Unicorn]

Watching thread with interested.

Just opened one of my A2000's it has a rev 4.0 board and looks like it never had a battery installed, no green fungus.

[Jope]

Originally Posted by LimpingNinja

1) Does the 512kb of Chip Ram even matter with the Vampire?

It does, but you can get a lot done if you mainly use RTG screens, as one tends to do with the Vampire. I don't own a Vampire, so I'm not that familiar with any custom chip emulation it has, so I'll refrain from posting any assumptions about that.

2) Will having such low Chip Ram cause any issues down the road?

It might, in normal productivity use you can get away without using a lot of Chip, but WHDLoad is happiest with at least 1MB and if you intend on doing modules with Protracker, then the amount of samples you can load is a bit limited.. Then again it didn't stop the maestros of the 90s making wonderful music that is playable with 512k of chip.. :-)

[LimpingNinja]

Thanks for all the details Jope, much appreciated. I will give this a run with my Vampire and decide if I want to keep using it in the A500 6a or the A2000A (rev4)

Originally Posted by Jope

I don't own a Vampire, so I'm not that familiar with any custom chip emulation it has, so I'll refrain from posting any assumptions about that.

From what I understand if you upgrade to GOLD CORE 3 (which is still not released) it comes with 4MB of emulated Chip Ram - which should sort the deal out in the future.

It might, in normal productivity use you can get away without using a lot of Chip, but WHDLoad is happiest with at least 1MB and if you intend on doing modules with Protracker, then the amount of samples you can load is a bit limited..

Yeah, I know there were some games that actually block and laugh at you without 1MB.

Then again it didn't stop the maestros of the 90s making wonderful music that is playable with 512k of chip.. :-)

Heh, definitely not including myself in that mix! I did some wonders in text based game programming, but damned if I have a musical bone in my body.

[LimpingNinja]

Originally Posted by Unicorn

Watching thread with interested.

Just opened one of my A2000's it has a rev 4.0 board and looks like it never had a battery installed, no green fungus.

Yeah, mine looks like it was never used, it's quite immaculate - the case and keyboard are amazing and the board looks factory new with no green fungus either; I was a bit demoralized by original searches for the Rev - though I guess it's cool to own one of 60,000 or so produced this far on :-)