A500 chip ram upgrade?

[kirk_m]

I saw this listed on fleabay recently.  I have the proper revision motherboard the seller states is required (A500 Rev 6a), and am considering purchasing the kit to upgrade the computer to 1meg chip ram (well, I would send it to someone like Acill to do it, if he feels up to it).  Is there any reason to NOT do this?

[Matt_H]

It's no different from putting a RAM card in the trapdoor slot. Why not just do that? Should be cheaper, plus no risk of breaking anything on the motherboard.

[kirk_m]

It's no different from putting a RAM card in the trapdoor slot. Why not just do that? Should be cheaper, plus no risk of breaking anything on the motherboard.

Ah, my bad.  I thought that the 512K trap door type of RAM expansion was fast mem, not chip mem.

[paul1981]

Ah, my bad.  I thought that the 512K trap door type of RAM expansion was fast mem, not chip mem.

It becomes Chip RAM with a slight modification to the motherboard (cut a trace). This is very well documented around the internet so should be easy to find. You'll be able to do it yourself too...it's easy peasy lemon squeezy.

[giZmo350]

Here's a good "How To" from AmiBay....

http://www.amibay.com/showthread.php?4722-A500-%28r6a%29-1MB-CHIP-RAM-Modification-Caution-dialup-users-excessive-H-W-pr0n!

Keep in mind.... that if you perform the 2MB chip mod using a 2MB Agnus + MiniMega + Trap Door 512KB, that you will no longer have any Fast Ram. You'll need to get fast Ram from the Zorro connector...  i.e., A590 or such. Or possibly an additional internal Fast Ram capability using the Kipper2K IDE+Mem board. http://www.kipper2k.com/a500fastmem.html

Also keep in mind  that if you perform the 1MB mod with the internal kit by adding the chips to the mobo that you will disable the trap door connector.

Personally, I play original games from disk with no Fast Ram (see my sig) and they run OK so far. Some games will crash at some point without Fast Mem though. Luckily the guys over at EAB http://eab.abime.net/ are always modding ADF games to run in Chip Mem only! :laugh1:

I'm still on the hunt for a board to add internal Fast Ram after performing the 2MB Chip mod. Would love to have a Kipper board w/o IDE. :laugh1:

[Acill]

I'd be more than happy to do it for you, but its very easy as other here said. For an A500 I wouldnt bother doing it over just getting a simple trap door ram card myself. NOW if you got a mega chip that would be another story. I'd do the 2MB chip RAM any time!

Let me know what you decide. I wouldnt charge much over my initial $45 starting rate and maybe not even that.

[psxphill]

Keep in mind.... that if you perform the 2MB chip mod using a 2MB Agnus + MiniMega + Trap Door 512KB, that you will no longer have any Fast Ram.

There is a 2mb upgrade that allows you to still use the trap door. I know because I used to have a revision 5 a500 with 2mb chip, 1.5mb slow memory & 2mb fast ram. It was awesome, it could run anything.

I still have the hardware somewhere, but it's not assembled right now.

[giZmo350]

Maybe you're thinking about an A500+?  A500+ is an odd animal. I should get one for the learning experience.

Bust that puppy out and post up!

[psxphill]

Maybe you're thinking about an A500+?  A500+ is an odd animal. I should get one for the learning experience.

Bust that puppy out and post up!

No it was definitely an a500. It's all in pieces spread in boxes unfortunately.

I started with a 512k slow memory upgrade, then added a 1mb slow upgrade that had a pass through so you could have 1.5mb. Next came the 2mb chip ram upgrade, which also connected to gary. IIRC this was a unique one in that it contained 2mb of chip ram & didn't use the motherboard chip ram or the trapdoor slot ram. I don't remember if I knew it was different to the others when I bought it.

[Acill]

Yup, I also did a 2MC chip RAM hack and had trap door RAM working back when I had an A500. Its a hack, but it worked well. Similar to what the MegaChip did.

[Dandy]

I saw this listed on fleabay recently.  I have the proper revision motherboard the seller states is required (A500 Rev 6a), and am considering purchasing the kit to upgrade the computer to 1meg chip ram (well, I would send it to someone like Acill to do it, if he feels up to it).  Is there any reason to NOT do this?

As far as I remember, populating the empty places for Ram on the motherboard leads to losing the functionality of the trapdoor slot.

I also have such a mobo and wanted to solder the missing Ram directly onto the mobo, but gave up this idea after learning that this would disable the trapdoor slot.

[Dandy]

Ah, my bad.  I thought that the 512K trap door type of RAM expansion was fast mem, not chip mem.

The type of Ram in the trap door is called "Ranger" mem.
Not as fast as 'real' FastRam, but faster than CHIP Ram.

[psxphill]

The type of Ram in the trap door is called "Ranger" mem.
Not as fast as 'real' FastRam, but faster than CHIP Ram.

It is exactly the same speed as chip ram. It suffers from the same slow down if there is a lot of dma activity, which is the only reason that chip ram is slow in the first place.

The trap door isn't actually ranger memory, it just appears at the same address as the 512k extra ram in the ranger prototype and then the third party boards which were based upon it. I believe this was true fast ram.

The fat agnus was an anti amiga inc (los gatos) project. Jay claimed it wouldn't work and that ranger should be the next step, which likely encouraged the chip guys even more to make it work.

[Dandy]

It is exactly the same speed as chip ram. It suffers from the same slow down if there is a lot of dma activity, which is the only reason that chip ram is slow in the first place.

The trap door isn't actually ranger memory, it just appears at the same address as the 512k extra ram in the ranger prototype and then the third party boards which were based upon it. I believe this was true fast ram.

German Wikipedia:

„Ranger Memory“

Neben Fast-RAM und Chip-RAM gibt es noch eine dritte Art von Speicher – gelegentlich Ranger Memory, unechtes Fast-RAM oder Slow RAM genannt. Er befindet sich auf Speichererweiterungskarten für den internen Erweiterungsplatz im Boden des A500 bzw. auf dem Mainboard des A2000.
...

(My Translation: There's a third type of memory beside Fast-RAM and Chip-RAM - occasionally called "Ranger Memory", "pseudo Fast-RAM" or "Slow RAM". It is located on Ram expansion boards for the internal expansion slot at the bottom of the A500 respectively on the motherboard of the A2000.
...)

So it seems the trap door Ram was very well called
"Ranger Ram" and also was slower (that's why it was also called "SlowRAM") than the 'real' FastRam at the expansion port at the left side of the A500.

The fat agnus was an anti amiga inc (los gatos) project. Jay claimed it wouldn't work and that ranger should be the next step, which likely encouraged the chip guys even more to make it work.

First time I hear this story since being an Amiga owner (1988)...