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Documentation about the Vampire hardware

Only 0.5mb Chip On A2000

David Kro

Posts 8
12 Feb 2021 18:53


Hello,

Recently I have installed V500+ in my A2000. But it shows only 0.5mb of chip in the taskbar. It means that almost no games can be ran in WHDLoad. I know that the very first versions of A2000 have only chip 0.5mb. Mine is probably this one. Original kickstart is 1.2. Do all A2000 have only 0.5mb of chip? What about later mainboard revisions? Will I be able to use WHDLoad on later revisions? How to override problem with low chip memory in WHDLoad?

Thanks for answers.


Vojin Vidanovic

Posts 1799
12 Feb 2021 19:15


There are ECS versions of a2000 board.
  Getting one is elegant solution, if possible.
 
  There were some modding possibilities to ad ECS chips, but might require a bit newer board then yours.
  EXTERNAL LINK 
  Lastly, you could try gold3 alpha core. You will loose rtg, fpu, floppy, and higher res then 640x but get chip ram and partial aga compatibility
  EXTERNAL LINK 
 
  Best is to be patient for gold3 final for vamp2. It should allow 2-11mb fast to be shown as chip, being faaast in access


Antony Coello

Posts 103
12 Feb 2021 19:36


Im in pretty much the same situation as you David.
 
  I have an A500 with a rev.5 board in it and a 1.5mb expansion which is slow RAM thanks to my Agnus not being fat enough.
  Hence 512kb chip RAM.
 
  @Vojin: If the boys did continue working on the V500+2 GOLD 3 core, I would be extremely happy.


Vojin Vidanovic

Posts 1799
12 Feb 2021 20:21


Antony Coello wrote:

    @Vojin: If the boys did continue working on the V500+2 GOLD 3 core, I would be extremely happy.
 

 
  I suppose once V4sa core gets mature, some basic features will be reduced and backported - about alpha core feature list, just improved in aga compatibility
 


Istvan Hegedus

Posts 20
13 Feb 2021 13:17


I have upgraded my A2000 with ECS Denise and a 2MB chip RAM solution plus a V500+. It works fine, I like it!
  You can find ECS Denise on the internet and buy ACE2b from icomp although that is not so cheap. You can find alternate 2MB solution on amibay.


David Kro

Posts 8
15 Feb 2021 08:55


Vojin Vidanovic wrote:

There are ECS versions of a2000 board.
    Getting one is elegant solution, if possible.

In that way is it possible to replace only a chip? 1MB of Chip RAM would be fine for me as WHDLoad will work. If the chip replacement do a job, which one to replace? Denise, Agnus or both? After replacement, will the whole 1MB be visible as a Chip RAM?


Vojin Vidanovic

Posts 1799
15 Feb 2021 10:30


David Kro wrote:

  In that way is it possible to replace only a chip? 1MB of Chip RAM would be fine for me as WHDLoad will work. If the chip replacement do a job, which one to replace? Denise, Agnus or both? After replacement, will the whole 1MB be visible as a Chip RAM?

ECS Agnus would be sufficient. but board can be a limit. In this video its rev4.3
EXTERNAL LINK 
Note that different versions are needed depending on your board

8372A - Amiga 500 from Rev 6 (NTSC/PAL); Amiga 2000 model B from Rev 6.0 to Rev 6.3 (NTSC/PAL); Commodore CDTV
8375 (318069-16 only) (PAL) - Amiga 500 from Rev 6 (PAL); Amiga 2000 model B from Rev 6.4 (PAL)
8375 (318069-17 only) (NTSC) - Amiga 500 from Rev 6 (NTSC); Amiga 2000 model B from Rev 6.4 (NTSC)

However, based on your description, I suppose you have oldest
A2000-A board, which have different DIP Agnus, that I believe is NOT upgradable

EXTERNAL LINK 
Thus, obtaining newer ECS based A2000 board seems to be best solution - v6.5 board.
EXTERNAL LINK 


David Kro

Posts 8
20 Feb 2021 15:46


I have checked the Mainboard. It is Amiga B2000 v4.1. It has Agnus 8371 - 3687 - 21. What would be the cheapest option? Replace only the Agnus will do the work? If yes, which version should I look. Icomp solution is definitely to expensive (instead of it I would like to find a 6.2 mobo)


Vojin Vidanovic

Posts 1799
20 Feb 2021 16:12


So far google and Amiga forum search does not show 4.1 is upgrade-able, so either speaking to some really a2000 experienced modder or getting the ecs board.

In general, replacing agnus should do it, maybe some small intervention is needed to turn the 512k slow fast to chip. But videos show 4.3 board and upwards interventions.


Eric Gus

Posts 442
20 Feb 2021 23:57


Im in a similar situation with my A500 .. and I am using the old old old Alpha Core3 to get around the entire chipram limitations since everything is run from the FPGA and I now have plenty of chipram and AGA on my A500 thanks to the core3 alpha .. Hopefully one day when work on the V4SA matures they can then look to backporting to the V2 and improve the CORE3 .. these kind of chipram/agnus issues will be moot. I am happy to loose RTG and FPU to resolve this really crippling problem with fixed mode Agnus chips (mine is NTSC only .. no PAL display modes) and limited to 512kb chip because its an early rev mobo .. would require hacking up the mobo and I wont do that to *this* Amiga (my actual first machine not some ebay/skip find)


Vojin Vidanovic

Posts 1799
21 Feb 2021 16:18


Making an image of an Coffin-or-AmigaOS with no fpu no rtg apps, set to max limited alpha gold3 Resolution and with some games and apps that work on alpha gold3 might be a good intermediate solution.


Ali B.

Posts 20
21 Feb 2021 19:30


You should check your board revision. Mine was shipped with Kickstart 1.2 and had 512MB chipmem, but is an B2000. The first A2000 actually are not upgradeable but as they are rare, worth a fortune. I changed my agnus back in the days... I think I used an instruction from a magazine. I do not remember, but have found this. Sorry that you need to use Google translate on it:
EXTERNAL LINK  Have fun.


Vojin Vidanovic

Posts 1799
21 Feb 2021 21:15


He has B2000 rev 4.1

It seems that procedure is same for all 4.x boards

Rough translation is

Find the jumper »J101« at the bottom right next to the connector for
Power supply CN400. This jumper position consists of three pins. Two of them are
connected by a small plug. Turn it over to the left so that it is the
Connects the middle with the previously free pin. Then you have to set the jumper »J102«
cut through. It has two soldering eyes and is about two centimeters to the right of "J101".
Then the connection between the soldering eyes of »J500« is cut. He is lying
about ten centimeters above "J102". Finished

For the Amiga 2000 you need an additional board
with additional RAM and Fat Agnus 8372B (e.g. Retro Chip from Pulsar).

There are instructions to replace Denise chip for ECS gfx modes too, but he is interested in chip RAM upgrade only.

It seems related video will be applicable
EXTERNAL LINK 


David Kro

Posts 8
26 Feb 2021 08:11


Yesterday I removed the original Agnus 8371 from v4.1 and installed the Agnus 8372A from my dead v6.2 (with jumper settings). Now the Amiga has got 1MB chip and 0MB fast :) WHDLoad works perfect now. I have tested some games, like: MK2, Superfrog, Cannon Fodder. I can confirm that Jan Beta's tutorial works with B2000 v4.1

Now I am looking for 8372A for my dead 6.2 to bring her alive. Does anyone have to sell?

posts 14