The basic A500... and 1Mb memory

[hamster]

Hi All... not a winuae problem as such but a query about ram...

When I got my Amiga in 1990 I got it with 512K and that xmas I upgraded it to 1Mb. I have a question and I'm pretty sure I know but I wanted to check with ye guys on this : Is the base 512K all chip ram or slow ram?

I'm thinking that the 512K standard expansion I got was slow ram?

Advancing a few years later... the A1200 had 2Mb and I guess this was all chip ram? I'm googling around for a nice article about ram in general for the Amiga but have ye come across a good detailed one?

It's great to still see Amiga sources for compilation on the net.

[RetroMan]

The A500 got 512KB CHIP RAM and the most 512KB Expansions were SLOW RAM

[hamster]

Thanks - and the fast ram were used in the add-on Accelerators?

[RetroMan]

There are also Trapdoor Expansions that are used as Fast Ram but AFAIK only those with the Gary Adapter .....

[Chuckles]

It is also possible to modify an A500 so that the trapdoor expansion ram will be used as chip ram (instead of fast or slow ram), bringing the total chip ram up to 1MB. Of course the mod requires that the A500 have the fatter Agnus chip, and the details of how the mod is done vary a bit depending on the motherboard revision.

[hamster]

Thanks for the info! Now can anyone emulate more free time?

[Shrub]

Originally Posted by hamster

Thanks for the info! Now can anyone emulate more free time?

Yes, but it requires a high end sundial

[Adeptus]

Originally Posted by Chuckles

It is also possible to modify an A500 so that the trapdoor expansion ram will be used as chip ram (instead of fast or slow ram), bringing the total chip ram up to 1MB. Of course the mod requires that the A500 have the fatter Agnus chip, and the details of how the mod is done vary a bit depending on the motherboard revision.

If I remember rightly, I saw a guide on bringing it up to 2MB chip...
Requires the right revision board, and from memory it requires you to solder a bunch of RAM chips on to the board.

[Overdoc]

Yep, but only possible on very late A-500s with Rev. 8A board which was also built into A-500+ models.
If you have an A-500+ you only need a 1MB trapdoor expansion; for a normal A-500 with Rev. 8A board you have to add 4 chips ( 512KB ) of ram.

[whiteb]

Originally Posted by Adeptus

If I remember rightly, I saw a guide on bringing it up to 2MB chip...
Requires the right revision board, and from memory it requires you to solder a bunch of RAM chips on to the board.

There was a trapdoor expansion for the A500 called Axram 4 (i think) made in Australia, it has capability for 4x 1MB PC simms, and dependant on the agnus in your motherboard, could have upto 2MB of the expansion used as CHIP ram, with the necessary modifications on the motherboard. (certain solder jumper blocks had to be re-wired, and some tracks cut).

I had (i think still have) one of these, and had my A500 set up for 1MB Chip and 3.5MB fast mem. Accompanied with my A530, gave my A500 1MB Chipmem and 7.5MB fastmem. The instruction booklet had diagrams of which solderblocks had to have which rewiring/track cut for which A500 revisions.