Fat Agnus output
9 messages in this thread
I have a friend who has an Amiga 500 with 1meg and fat Agnus and a GVP
harddrive setup with 2megs of RAM. For some reason he can only get 512K
with the fat Agnus when he should get close to 1meg. He consulted a tech
person who said that he must make a few modifications on the motherboard. I
was not sure this was necessary since I have not heard of this problem with
other Amiga 500. Can anyone explain why this must be done to get more then
512K allocated for graphics. I would think the new fat Agnus would take
care of this??
Robert
Robert, A500's do come in several varieties re Chip Ram. Some require a
motherboard mod to 'activate' the 1meg Chip ram, others don't. Don't ask
me why, or anything, they just do.
The modification is pretty minor. It involves cutting a very small trace
on the motherboard. A friend of mine did it about six months ago, and it
went fine — he used an exacto knife for the 'operation' 🙂
There will be several files in the Amiga libraries that describe the exact
mod… I'd suggest doing a search for FAT AGNUS, CHIP MEMORY, etc to find
the files.
If it's not in the file you get, be warned: This voids your warranty. If
you are not handy with an exacto knife then I'd have a dealer do it for
you. Better cautious than sorry!
–jp–seattle–
Thanks alot, I wonder why that is. Does it start with a particular version
motherboard or is it random? Anyway, going to look for the file.
Robert
I think it is due to what motherboard you have. I have a 500 also, and
performed the cut trace on mine. I've been working with 1 meg of CHIP for
over a year now with no visible problems. I also have a 030 board with 4
megs of 32-bit ram, just upgraded to 2.04 fine, and just purchased the new
ECS Denise to play with!
Can you tell me how you did it? can't seem to find the instruction in the
files.
I do not recall off hand. I had to cut a trace on my motherboard. I
purchased my chip through Grapevine group, and they included a very
informative sheet of paper that explained different ways of doing it
depending on what version of motherboard you had. You may want to give 'em
a call, and see if you can get ahold of that paper. They have an 800
number, and advertise in just about every Amiga World.
Ok, thanks for your time!
Well, I did a search and could not find any such file. Can you tell me what
section it is in?
Thanks for your help!
Robert
Robert,
You must make modifications to the motherboard because an
additional address line must be activated.
Don