ECS Upgade for A500

[weirdami]

I have an Amiga 500 that has a mysterious silver box in the trap door that someone wrote "ECS upgrade" on. Any ideas what the deal it is?

There's also a switch on the back of the A500 case. Is that related?

[skurk]

I have no idea, but it sounds very interesting.  Can you post a picture of it?

[weirdami]

It's fully contained in the silver colored metal and is triangular shaped to fit in the hole and has only the connector exposed.

[HyAmi]

I think it's a 512K memory upgrade, one of the early ones. I have one laying around somewhere that suits your description.

[reddwarfer]

Yes!
I have one of them in my A500, don't think its an ECS upgrade. Mine has a 512K memory expansion and a battery backed clock in it.
It should say 'A501' on it

[alexh]

There is a chance that when they sold A500's they had two different memory expansion boards for sale at two different prices.

[reddwarfer]

A501 on eBay

Is this the expansion your talking about?

[yock1960]

You should take it out, de-solder the places where it's held together, take the case off and check out the battery. I bought two of these on eBay a few months ago, one battery looked & checked good, the other the battery was corroded. The funny thing was, the board for the corroded one, overall looked better (cleaner) than the one with the 'good' battery. I removed the battery, cleaned & scrubbed them both with electronics cleaner (Radio Shack #64-4345), put a new battery in the one and they both work fine.

[Speelgoedmannetje]

It could be a fatter agnus (or named something like that) has been installed, wich supports 1mb chipmem. One gets practically an A600 compatible A500.

[weirdami]

@reddwarfer

It does look something like that, only not rusty. It's all shiny. :-) Except, I should note, if it matters, that there are three indentations around the edges of the trap-door facing side (two on one long side and one on the other) that look like solder mouth points to keep the case on. And, no stickers, just the permanent marker "ECS upgrade".

I don't have a soldering gun so getting this bad boy open to see the innards would damage the case beyond repair.

[weirdami]

Is there a command (say on a workbench disk or something) that I can type in to get details that would say definately what this is?

Speelgoedmannetje wrote:
It could be a fatter agnus (or named something like that) has been installed, wich supports 1mb chipmem. One gets practically an A600 compatible A500.

[Kronos]

"avail" would tell you how much RAM there is (minus the 512k on the A500).

If it tells 1MB of Chip-Mem you got yourself a Big-Agnus for sure. If it's only 512k it still might be a Big-Agnus, that just hasn't been activated (change JP2 and "turn-off" trapdoor-expansion9.

[yock1960]

weirdami wrote:
Is there a command (say on a workbench disk or something) that I can type in to get details that would say definately what this is?

Well, if you're running WB 2.04, put your Install disk in & run ShowConfig. It will show whether or not you have ECS chips, what your memory nodes are, CPU, etc. Otherwise, go to Aminet and d/l Sysinfo.lha.

Or open a shell window and type 'avail', that will at least show how much of what type of memory you have.

[Tenacious]

My A501s are all fully enclosed in sheilding as you describe.  The shielding seems to be a "cover their butts" measure for Commodore with the FCC.  I've never noticed interferance without the shielding except near a shortwave reciever.

Even though my A500s all came with 1 Meg Agnus chips, they would only address 512 K of true chip ram on the motherboard.  The A501 was mapped as "slow-fast" ram in the stock configuration.  I changed all of my machines to 1 Meg, except one I changed to 2 Megs of chip.

Maybe someone modified your motherboard for 1 Meg of true chip ram and made the notation on the A501.

I doubt the switch is a stock part.  What is the switch wired to?

[weirdami]

I finally was able to plug this thing in and I discovered that the switch controls making it boot to an "insert workbench v1.3" hand screen and a "2.8 Roms (37.175)" disk inserting itself animation screen. That's probably 2.0, not 2.8, but I'm running it with the black and white out to a television through a vcr and it looks like an 8. :-/ Anyhoo, I guess "ECS Upgrade" means you get ECS chip set. And the switch is for toggling between OCS and ECS. Neat.

Now, someone can tell me what company made this gizmo, or if some A500's came like this from Commodore. Maybe I'll try putting in some disks and trying that showconfig idea.


edit: Yup, showconfig shows "ECS NTSC Agnus" and "Normal Denise".