Upgrade Ram to 1 MB Amiga 500?

[Super TWiT]

I know this probably has been asked before, but a google search didn't seem to reveal any answers. How do I upgrade the ram on my amgia 500 to 1 mb? I have a fat agnus chip.

[tone007]

All that takes is a standard 512KB upgrade in the belly of the A500.  They're all over the place.

http://cgi.ebay.com/Amiga-500-1-2-meg-ram-Expansion-just-plug-in-and-go-GWO_W0QQitemZ310214418058

[Super TWiT]

That doesn't upgrade the chip ram does it?

[tone007]

You should show 1MB Chip RAM after installing one of those, unless I've never looked closely enough at my 500s.

[Super TWiT]

See I thoguht that's what fast ram was...

[tone007]

Well, that depends.

On OS1.3, it all gets lumped into one group of available memory on the little display on top of Workbench, that one doesn't let you know what kind of memory you've got.

If you're running 2.0 or higher, it splits it out to available chipram and available fastram.

These add to the chipram as far as I've seen.

[save2600]

SuperTwit, do you have an A500 Plus? Or do you live here in the States? If you have a regular A500 and you add the 512kb expansion to the trapdoor, chances are you'll end up with 512kb Chip and 512kb Fast. You need to determine what mobo revision you have and go from there. Most A500 mobo's need to be modified (it's really easy to do) in order to take advantage of the 1mb capability of the Fatter Agnus. Do a search on A500 modifications after you've determined your mobo revision...

[Super TWiT]

Wikipedia says that a trapdoor expansion is fast ram. It also says that the amiga 500 is expandable to 1 mb of ram directly on the motherboard. I have an a500 and I live in the US. I believe I have a rev 5 board iirc. I do have a fat agnus.

[save2600]

Some (not all) A500 mobo's do indeed have the solder pads to add the extra 512kb of memory. It'll be a crap shoot if yours does.

@Tone007: the configuration of the mobo (Gary, Agnus and the expansion RAM) determines how the memory is split - not the OS. It only appears that way on OS1.3 as Workbench adds the two values together. OS2.x+ is just a little more revealing, showing the difference between the two.

[tone007]

SuperTwit, do you have an A500 Plus?

That's a good point, I usually play with 500+s.

So you'll probably need one of those boards and a motherboard hack, I haven't seen a Rev 5 with the extra room for chips on the board.

I took for granted how easy it was to get 2MB Chip ram on mine.

[Super TWiT]

So, if I wanted to upgrade the chip ram, either way I would have to do some soldering huh... Would I receive decent capatibility with applications if I just upgraded the trapdoor memory, because I REALLY don't want to solder anything. (My soldering skills are poor, and I don't want to practice on my amiga board!) My real intent is to make this an ecs machine so since I have the fat agnus, I could just plug in a super denise

[tone007]

Games (especially older ones) were mainly designed to work with the plain old A500 with the trapdoor memory upgrade, you can actually lose compatibility hacking around with things, or so I've heard.

[save2600]

Yes, you can just pop in the trapdoor RAM and Super Denise and still yield great compatibility. Only a handful of games took advantage of the extra Chip RAM anyway. If you're working with graphics and sound however, you'll want to do the Chip RAM mod eventually and get yourself some Fast RAM for the side expansion port.

Only really old (like software written during the OS1.0/1.1 time) or poorly written software will "break" with the addition of Chip RAM, so I wouldn't worry about it.

[Super TWiT]

Do I even need a ram expasion to use most ecs software?

[Jope]

You do not have to solder the chips into the motherboard for 1MB chip. That's a lot of trouble and you'd lose the trapdoor anyway if you did that

• , so why bother.

You can just plug in the trapdoor expansion, then you need to reconfigure two solder pad-style jumpers on the motherboard.

Also a 1MB capable Agnus is needed. On a Rev6 A500, this is almost guaranteed, on a Rev5 you need to upgrade the Agnus.

Look at aminet docs/hard for the instructions.

• it is possible to retain trapdoor slow RAM at $C00000 and have 1MB of chip RAM on the motherboard, but that is a more involved hack.