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Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: Zeela on May 07, 2004, 01:21:17 PM
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Hi,
I have some sort of Amiga 500 at home right now.
To me it seems to be a regular A500 (not a A500+).
it displays the nice Kick 1.3 image of a WB disk when started. Ir boots WB 1.3 fine. So far all fine, a regular A500 you might think...
But when done booting and WB comes up I have around 900 kb free memory and the trapdoor expansion port is empty.
So its a A500 with 1mb memory but not a A500+? I thought A500+ ran WB 2.x?
What type of Amiga is this? And is there a way I can find out if the extra 512kb is chip or fast mem?
Please help
//Zee
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Zeela wrote:
What type of Amiga is this? And is there a way I can find out if the extra 512kb is chip or fast mem?
Run NoFastMem and see if you then have 0.5Mb less memory free????
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Does it say A500 Plus on the top right or just a C= Commodore logo?
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Also check the sticker on the bottom :-)
AFAIK the A500+ is always labeled Plus, unless someone has changed the case / motherboard over.
Isnt the a500+ also supplied always with 2.04 roms?
Unless they have been changed...
It sounds like you have an Amiga 500, with 512K Ram expansion somewhere.
Kev.
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AMIGA 500 =
(http://www.abc80.net/Datorerna/Commodore/amiga-500.gif)
AMIGA 500+ =
(http://www.abc80.net/Datorerna/Commodore/a500_plus1.gif)
Sorry about the big photos, but note the different badges on the left hand side.
Hope this helps :-)
Kev
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Sorry, im in work so i cant photoshop the size of the images heh :-)
- edit AGAIN Found nice small photos now :-)
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The case is like the first on above (the AMIGA 500).
So the case is not from a A500+.
And it has 1.3 chips... So the internals shouldn't be a A500+ either.
And there is no expansion in any of the ports. Not in the trapdoor and not in the side port (whatever it's called).
I tried to add a 512k expansion in the trapdoor, but that didn't give me 1,5 mb, just 1mb... And when i used the "off"-switch of the expansion card it left me with just 512k...
So I don't know what this beast is!
// Zee
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Its an Amiga 500. When you have NO ram expansion in the trapdoor, its reporting as 512K. And with the 512K Expansion ON you get 1mb. Amiga 500 :-)
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Perhaps its an Amiga 500 with the 1 meg chip ram hack?
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LinchpiN wrote:
Its an Amiga 500. When you have NO ram expansion in the trapdoor, its reporting as 512K. And with the 512K Expansion ON you get 1mb. Amiga 500 :-)
Well, what I tried to explain was that without a ram expansion in the trapdoor its reporting 1 mb. When I added a ram expansion it still reported 1 mb and when I used the off switch of the ram expansion (still in the trapdoor) it reported 512k. When I remove the expansion it gives me 1 mb again.
Well, it's a puzzle...
// Zee
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Orjan wrote:
Perhaps its an Amiga 500 with the 1 meg chip ram hack?
Hmmm... What's that? But it sounds like it could be!
//Zee
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Orjan wrote:
Perhaps its an Amiga 500 with the 1 meg chip ram hack?
Either that, or someone put 1.3 into his A500+ (for better game-compability), and later exchanged the case with one from an A500.
Remember these girls are between 13 and 18 years old, and we all know that girls of this age don't follow ANY logic ....
... another question would be if the "logic" of older "girls" is any better than no logic at all :-P :-D :-P :-D
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Either that, or someone put 1.3 into his A500+
But that would not make the miggy report only 512k total ram with the Expansion board in and switched off...
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Hmmm...
I found a site on the net
http://atzesgym.servebeer.com/~amiga/amigaemulation.de/multi/modelle_e/a500.php
That claims that there was three models of the original A500.
The A500, A500C and A500P.
Reading the descriptions it seems like I might have an A500P.
What do you guys think? If it's on the net it must be true? :-)
// Zee
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Dont beleve everything you read on the net :-)
Seems to be the one, pity there is no actual Model # stamped on the amiga, that you can link up with the site. Basically, i would just use the Expansion to get the max amount of memory i could and then have some fun :-)
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Do A500 Trapdoor expansions work in A500+'s at all?
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bloodline wrote:
Do A500 Trapdoor expansions work in A500+'s at all?
If they don't why do the A500+ have trapdoor? Or it might not have a trapdoor? I've actually never seen a A500+ in real life.
// Zee
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I've heard rumors that Commodore was actually putting A500+ motherboards in A500 cases when the supplies of regular A500 mobos were low. The result of this was an A500 with 1MB chip ram on-board and KS1.3. :-)
Do a google search in groups for more info on this.
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x56h34 wrote:
I've heard rumors that Commodore was actually putting A500+ motherboards in A500 cases when the supplies of regular A500 mobos were low. The result of this was an A500 with 1MB chip ram on-board and KS1.3. :-)
Do a google search in groups for more info on this.
Why on earth whould they do this?
1. When the A500+ was launched, the A500 was already cancelled, atleast to my knowledge
2. If point 1 ( above ) is incorrect, then why would they take 500+ mb´s and put in 500 cases? Why not just build 500+´s instead?
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I've heard rumors that Commodore was actually putting A500+ motherboards in A500 cases when the supplies of regular A500 mobos were low. The result of this was an A500 with 1MB chip ram on-board and KS1.3.
But what happens then with Hardware Incompatability? People would then think they had an Amiga 500, and get an 512k Expansion card for it, and it wouldnt work (if it was designed for an A500+)
Do you have a link to this info?
Cheers
Kev
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Open it up.
Look at the motherboard.
Job done.
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On the mobo, there is a stamp.
a500 looks like this =
(http://proxify.com/p/011110A/http/amiga.emugaming.com/a500rock.jpg)
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I think 500/500+ trapdoor expansions are pin compatible, but 500 expansions won't work in a 500+ (and vice versa) because of some memory addressing differences. At least, not to their advertised specs.
As for the different models of 500s available, I've got a really strange one: An OCS A500 with a case badge saying "A-500."
I guess the best way to solve the mystery behind this machine is to pop the lid, see if there's anything attached inside.
Something else I just thought of, I think there were some A500 RAM expansions that connected to the trapdoor and Gary, but still had passthrough connectors to attach something else (RTC? One of those PowerPC emulators?). Make sure you're dealing with the genuine trapdoor, and not an extender board.
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But when done booting and WB comes up I have around 900 kb free memory and the trapdoor expansion port is empty.
There are many ways to do this, all involve hacking the hardware.
1. Agnus chip expansion. The Megachip is still available, which replaces the existing Agnus with a plugin board containing a newer (Fat) Agnus and 1.5MB. There might have been older 1MB Agnus versions of this.
2. On the Rev 5 A500s, only half of the 16 memory sockets were filled. With the correct chips, a 1MB Agnus and a soldering iron you can expand to 1MB chip easily.
3. On the Rev 6 A500s, a revised 4 (?) chip RAM solution was used. As I recall, you can still expand this by piggybacking chips on top of each other (to put it simplistically).
Most likely explanation is the Agnus expansion. Open it up, and you should see something like http://www.amiga-hardware.com/dkbmegachip.html sitting in one of the chip sockets.
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Hi,
The Best way for know what type of Amiga is opening and check inside the MotherBoard Series Number, and take a look if have any Memory HAck, or came with Memory expansion Socket.. Any A500+ Came with expansion socket for put on a 256k Chips..
Regards!
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A friend of mine had a 500 with empty slots inside for DIL memory packages. So we slaughtered a 512KB trapdoor memory expansion which used the same chips (A501?) and soldered them in. I even think there were jumpers or some wires you had to cut/scrape to map these as chip and not fast-ram. Maybe mapping internal DIL's as fast-ram is not possible at all? We did this to be able to load larger modules into Protracker, as 512KB chip memory was not enough for modules >400KB. And when we put another 512KB in the trapdoor it wasn't recognized. I also think there are some connectors on the trapdoor expansion to shut off extra memory, this also affected the memory we just added.
This motherboard was a revision 5 if my memory serves me right, but it is 10 years ago, so I'm likely to be wrong... The machine was however a KS1.3, not a 500+. It worked nice at the beginning, but the solder equipment we used was not really suited for the job, so over time the machine became more and more unreliable, I think I can blame that on overheating of the memorychips.
Anyway, if you pop off the lid, you can easily see the revision number, and if 1/2 off the DILs are mounted at a later date, you could most probably tell this by some bad soldering or similar :lol:
As I recall there were 8x64KB DILs in originally, with space for another 8x64KB, totalling 1MB, at least on the rev.5 mobo.
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And I think this machine had a Fat-Agnus as standard...the only thing we did was add 128KB DIL's.
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Hi,
I took a quick look under the hood of my A500 this weekend.
What I found out was that it was a A500P.
There was a yellow sticker saying A500P attached to the place where the board revision and model are on the mother board.
// Zee