View Full Version : Jumper on a4000 really broken?

24th July 2009, 02:39
I noticed on bboah.com that there is a jumper on the a4000 mobo that set the chip ram to 8mb, but it won't work, why is this?

24th July 2009, 04:07
I seem to recall reading some where that it isn't technically broken... it's just not implemented. I think the main reason sited was the bankruptcy of Commodore. If Commodore hadn't gone bankrupt that might have been implemented. I'm curious as to what it would take to do so. I'm certain a lot of wiring and changing to various parts of the board could do it. We could always ask Dave Haynie. He might know.


24th July 2009, 04:09
Crap. I was trying to reply to Dreamcast270mhz's post and somehow I created a new topic. Is there a way to merge this with his question please?

24th July 2009, 06:09
OK done :)

24th July 2009, 09:10

For an A4000 (or any AGA machine) to manage 8MB chipram, It would consitute re-designing & replacing the current ALICE with a New improved and higher spec version...

This jumper is one of those odd things that C+ did with no explanation as the AAA chipset was already underway...

So... Don't bother looking for an A4000 with 8MB chipRAM as they simply don't exist..
Unless you count WinUAE of course :D

TC 8)

24th July 2009, 10:36
No there is no available A4000 with 8MB addressable chipram. I never stated that, but I recall reading somewhere that the only reason it didn't get implemented was because Commodore went bankrupt. That doesn't mean that it isn't feasible to make work, it would just require a lot of work, which someone like me couldn't do. You say a newer Alice chip would be needed, could that be fabricated into some sort of FPGA or something that either clips onto the Alice, or removes the Alice and replaces it? I am curious about this as to whether this could even be done with an upgrade to the chips. I would think there would need to be more copper tracks in the motherboard to handle the additional information. Could someone who has more knowledge of Electrical engineering elucidate me on this please? Thank you.


24th July 2009, 12:32

I do agree with you my friend simply from a "can do" point of view and I'm sure Alice could be cloned & spread-legged using an FPGA...

The real issue is though why to bother, There's no software out there to take advantage of the extra ChipRAM and real Amiga software devopment ceased long ago.
(Please Guy's no comments regarding OS 4, I'm not even going there :twisted: )

Would take a lot of resource with little return...


If Individual Computers were to create an updated Clone A chipset based on the AGA Girls (Hint Hint Indivision AGA) then I'm sure adding the extra addressing capability to Alice would not be that big an issue.

Whichever way you look at it, the future looks good

TC :)

24th July 2009, 22:17
Interesting. If I was going to do something like that I wouldn't be doing it for a return. If I wanted a ROI for any sort of electronic work, I wouldn't try with the Amiga. There are way too many more talented than me people out there making magic on the classic machines. It was simply a question of could it be done, and if so, how? I think that's most the fun of doing things like this; Just to see if it can be done. Thanks for the info sir, and congrats on finding the RAM you needed. I think I may be getting an A500 sometime in the future as well.