Amiga 500 upgrade questions

[Soviet Conscript]

an amiga 4000 is a bit out of my price range right now so i just have a few questions about upgradeing the amiga 500. looked on the web but i wanted to see if i can get a clearer answer here

how do you know if your amiga 500 is an early version or one with a "fat agnus" chip for the purpose of upgradeing the ram to 1 MB chipram.
where do you get a "fat agnus" chip, how do you know if the chip is a "fat agnus" and is it hard to swap the chips?
is upgradeing the rom to higher kickstart versions difficult?

[robotriot]

how do you know if your amiga 500 is an early version or one with a "fat agnus" chip for the purpose of upgradeing the ram to 1 MB chipram.
where do you get a "fat agnus" chip, how do you know if the chip is a "fat agnus" and is it hard to swap the chips?
is upgradeing the rom to higher kickstart versions difficult?

Check http://en.wikipedia.org/wiki/Fat_Agnus for identifying the chip you have (either go by motherboard revision or by the chip number). Also, do a Google Image Search on Fat Agnus to get some pictures of the chip.
Upgrading kickstart ROMs is very easy since pretty much all of the chips, including the ROMs, in the A500 are socketed. You just take the old one out of the socket and stick the new one in, done. For compatibility reasons, it might be wise to get a kickstart switcher so that you can switch back to an older version if certain games refuse to run.

[98PaceCar]

Just swapping the actual chip is only the first part of getting the system to address the full 1mb as chipram instead of split between chip and fast. It's been a LONG time since I did mine, but I believe it was cutting one trace and bridging another. The instructions should be out there. It was pretty easy to do and well worth the mod. I even have one system that had a switch installed to allow you to have either setup.

I'd also second the recommendation to get a rom switcher. Some games don't like the newer roms, so it was always nice to be able to downgrade from the keyboard. They should be pretty cheap and easy to find.

[kedawa]

My A500 has some sort of mod where the trapdoor ram acts as chip ram instead of fast ram. I don't know if that's the best configuration, but it seems to work fine with all of my software.

[zektor]

As for changing the kick.rom:

If you have a rev 5 board it is not as simple as just swapping the rom. There are directions online, and I will not go into great detail, but there is some more you have to do to the board to get it to work.

Luckily I have a rev 6a, and with this I was able to simply swap out the rom and it works great. There is a seller on ebay right now that is selling A2000 kick 3.1 roms for $20, which work with the A500. This is what I did.

As for a rom switcher, don't even bother. I use a software kicker (Relokick) and it works just fine on the software that needs 1.3 to run. Just boot Relokick and swap it out with the game in question on reboot.


If you DO end up getting a rev 5 board however, all hope is not lost for 1MB chipram. I have an ICD AdRam card for sale that gives a rev 5 board 1MB of chipram. Oddly enough, it ONLY works on the rev 5 board! So, if you get one, let me know and you can have it for a steal, since I cannot use it at all. Has a brand new clock battery too

[icbrkr]

I've never done anything besides switch out the kickstart ROM on any system that I've ever owned except for my A1000 and my early model 3000. That said, I have seen some 2.04 500/600/2000 kickstarts with 2 legs jumpered together with a wire that was soldered to the legs. That could be the 'fix' or it could be something else.

[Soviet Conscript]

do you have to open the system up to find out the MB revision?

i just pulled my two digusting yellowed cracked units out of storage. to my suprise one acually had an extra ram card instaled in the trapdoor, i never even knew.

[Soviet Conscript]

what about the flicker fixer? will that allow me to use the amiga on a VGA monitor?