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Thread: WTB UK Action Replay Mk 3 for Amiga 500 and 1.5MB+ trapdoor memory card
CLXIV 09:53 29th July 2021
Hello, I'm looking for an Action Replay Mk 3 for Amiga 500 and 1.5MB+ trapdoor memory card to take total up to 2MB.

Payment via anything with buyer protection (so not Paypal gift).
[Reply]
Harrison 16:04 29th July 2021
With the original A500 you can only have a 512KB trapdoor expansion to increase the ram. And depending on the version of the Agnus chip this trapdoor expansion would either add an extra 512kb slow ram, or would increase the chip ram to 1MB, which was required in later games.

With the later A500 Plus you could add a 1MB trap door expansion to increase the on board 1MB to 2MB chip ram.

For fast ram you need to either use a sidecar fast ram expansion, or other sidecar expansions that also added ram such as GVP harddrives. And some more recent fast ram expansions that piggyback directly over the agnus chip.
[Reply]
CLXIV 16:57 29th July 2021
Originally Posted by Harrison:
With the original A500 you can only have a 512KB trapdoor expansion to increase the ram. And depending on the version of the Agnus chip this trapdoor expansion would either add an extra 512kb slow ram, or would increase the chip ram to 1MB, which was required in later games.

With the later A500 Plus you could add a 1MB trap door expansion to increase the on board 1MB to 2MB chip ram.

For fast ram you need to either use a sidecar fast ram expansion, or other sidecar expansions that also added ram such as GVP harddrives. And some more recent fast ram expansions that piggyback directly over the agnus chip.
Are you sure? What about stuff like this?

https://bigbookofamigahardware.com/b...ct.aspx?id=927

Or the site just got it wrong? I just opened the first memory expansion in the list.
[Reply]
J T 06:56 30th July 2021
What do you need an A500 with 'so much' RAM for anyway?

What are you wanting to do with it that the standard trapdoor expansion won't?
[Reply]
CLXIV 10:59 30th July 2021
Originally Posted by J T:
What do you need an A500 with 'so much' RAM for anyway?

What are you wanting to do with it that the standard trapdoor expansion won't?
Action Replay "sq" command (save memory contents to memory) in 1MB games.
[Reply]
Harrison 11:23 30th July 2021
That looks like a very unique ram expansion because it includes a Fat Agnus that provides the additional chip ram support. I've never seen one of those. With the majority of A500 trapdoor expansions, the amount of chip ram will be dictated by the version of Agnus chip on the motherboard.

With an Action Replay fast ram would be better then chip ram.

How can you though when the AR plugs into the side expansion? A lot of sidecar expansions include a Pass through so you can plug another expansion into the other side. It was common to see 2 or 3 expansions all plugged in together, making as A500 extremely wide. So you could have a AR plugged into a fast ram expansion, plugged into the A500.
[Reply]
CLXIV 13:03 30th July 2021
Ahhh OK so with what was available in the 90s, the only way to save state to memory in 1MB games would be an Action Replay plugged into a sidecar memory expansion?

Of course now we have some modern options too - any idea if these would provide that same functionality?

This one involves some kind of Gary adapter: https://amigastore.eu/en/710-amiga-5...ion-rtc.html#/

This one pops straight onto the CPU socket and then the CPU goes into the memory card (I think): https://www.ebay.co.uk/itm/333971306155?ul_noapp=true

I really like the looks of the sidecars actually (the ones that follow the profile of the Amiga) but I guess they'll be very rare and expensive, so I'll probably grab either of the above if they'll achieve the same thing.
[Reply]
Harrison 00:18 31st July 2021
Yes the sidecar expansions will be hard to find these days, and probably quite expensive. But worth a look.

The holy grail of A500 expansions is the GVP 530, which is an 030 accelerator, SCSI harddrive controller, and up to 8MB fast ram. If you ever saw one of those for sale grab it. It's little brother is the GVP HD8+, which is the SCSI harddrive and fast ram, but not the cpu. I've got one of these with the optional 80286 PC hardware emulsion card. Great card.

Take a look at this interesting link:

"2MB RAM Amiga 500/500+ :: BooBip.com" http://www.boobip.com/hardware/A500_2MB

It has a section sorn the page that helps you identify the version of motherbord your A500 has. This will tell you what trapdoor expansion it's compatible with so you will know if you could add 2MB this way, or be restricted to 1MB or 512KB upgrade possible.
[Reply]
CLXIV 22:00 31st July 2021
Originally Posted by Harrison:
Yes the sidecar expansions will be hard to find these days, and probably quite expensive. But worth a look.

The holy grail of A500 expansions is the GVP 530, which is an 030 accelerator, SCSI harddrive controller, and up to 8MB fast ram. If you ever saw one of those for sale grab it. It's little brother is the GVP HD8+, which is the SCSI harddrive and fast ram, but not the cpu. I've got one of these with the optional 80286 PC hardware emulsion card. Great card.

Take a look at this interesting link:

"2MB RAM Amiga 500/500+ :: BooBip.com" http://www.boobip.com/hardware/A500_2MB

It has a section sorn the page that helps you identify the version of motherbord your A500 has. This will tell you what trapdoor expansion it's compatible with so you will know if you could add 2MB this way, or be restricted to 1MB or 512KB upgrade possible.
Ah this looks quite similar to my first link ^ with the Gary adapter. That 1.5MB slow on a rev 6A would do the trick nicely, provided the AR3 can see it.

I did some testing with virtual RAM configs in WinUAE and every 1MB game tested failed (in various and sometimes dramatic ways) but then the WinUAE author does say to use built-in save state functionality and avoid using AR ROM saves so it's not really an ideal test.

I'll grab one of these little guys with the Gary adapter and see how I go. Just gotta get my hands on that AR3! I've seen them so many times on eBay around £50 but of course now that I've actually resolved to buy the bloody thing they're nowhere to be seen at remotely sensible prices...
[Reply]
Harrison 13:17 1st August 2021
I do have an Action Replay for the A500 but it's currently in storage. I've no plan to use it again so would be willing to sell it. But I can't give time scales on when I could find it, so if you get stuck trying to find one get back to me and I will try to locate it.
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