#4000 Jumpers
7 messages in this thread
I have noticed two interesting jumpers on my A4000's motherboard. The first one
J214 allows switching between two positions : VBB and 8M (probably 8MB)
Presently, it is in the VBB position. The other jumper, even more interes- ting
is marked CHIP RAM and offers switching between 2MB and 8MB. It is, of course
in the 2MB position presently.
What happens if I change these jumpers to the 8M position ? I hesitate to do it
but I a very temptated…
Can somebody help ?
Philippe REUX
Motorola 68040 on AutoPilot 1.78
ONE PLANET, ONE PEOPLE PLEASE
If you're lucky, nothing will happen, if not…
There were plans to make chipmem expandable to 8 megs but they were scrapped
along development of the A4000, so the megs you've got are all you're gonna
get…
Cheers,
// Christian "ELP" Busse
\X/ near Frankfurt, Germany
maybe someone else can create an 8mb chipram upgrade for the 4000 soon
I believe that would mean a change of adressing the memory. Isn't it so that
only the first 2 megs are mapped/reserved as "Chip Ram" (so you have a 1 meg
"hole" in the address space if you have only 1 meg chipmem) and fastmem starts
from there?
// Christian "ELP" Busse
\X/ near Frankfurt, Germany
I wouldny know cause i dont know much about a 4000,but i say it's noot
impossible
Philippe,
I would not recommend changing the jumpers, especially the one for CHIP RAM,
since your present Agnus and Denise chips can only address 2MB. Since you do
not know what they do, doing so could seriously impair and adversly impact the
future use of you computer and investment.
I hope this helps ….
muv — AutoPilot vs 1.80 from Mpls/St. Paul
Daniel A. Darlington c3ltd@winternet.com
Phillippe,
nothing will happen, when developing the board, this jumper was used to switch,
te option was taken out before the 4000 was launched.
It might crash or damage your system perhaps, so beware.
If you did try, don't forget to tell us. 😉
Lieven Lema
…on autopilot from Belgium.