A500 RAM Expansion - any point to 2MB in the trapdoor?

[oracle_jedi]

I need a few parts from amigastore.eu and with shipping being what it is, considering adding a few more nice-to-haves, including replacing the old, clunky, heavy and gets-too-warm A500 512K RAM expansion.

 

Amigastore.eu offers a nice new compact unit, in either 512K or 2MB configurations.  There's also a RTC option I will probably skip, as my Amigas all think it is still 1992, and I'm cool with that.

 

But my question is; is there any point to a 2MB-in-the-trapdoor expansion for an A6 rev Amiga 500?  I used to have a Baseboard RAM expander once in the A500, which bumped me to 2MB, but it required a ribbon cable to an adapter to plug into one of the main ICs, and it only worked if I added the Baseboard shim into the boot disk, so I am pretty sure no commercial games would be able to recognize it or use it.  Anyone know is thats the same deal with these 2MB expansions?   I always thought the A500's trapdoor was limited to 512K and anything more would require some modding.

 

 

 

[Tuxon86]

29 minutes ago, oracle_jedi said:

I need a few parts from amigastore.eu and with shipping being what it is, considering adding a few more nice-to-haves, including replacing the old, clunky, heavy and gets-too-warm A500 512K RAM expansion.

 

Amigastore.eu offers a nice new compact unit, in either 512K or 2MB configurations.  There's also a RTC option I will probably skip, as my Amigas all think it is still 1992, and I'm cool with that.

 

But my question is; is there any point to a 2MB-in-the-trapdoor expansion for an A6 rev Amiga 500?  I used to have a Baseboard RAM expander once in the A500, which bumped me to 2MB, but it required a ribbon cable to an adapter to plug into one of the main ICs, and it only worked if I added the Baseboard shim into the boot disk, so I am pretty sure no commercial games would be able to recognize it or use it.  Anyone know is thats the same deal with these 2MB expansions?   I always thought the A500's trapdoor was limited to 512K and anything more would require some modding.

 

 

 

There are better solution now for extra ram on an A500. You can get an 8meg/SD or CF card IDE that goes under the CPU, or get an accelerator. The trapdoor ram upgrade can be turned into chip ram by a bit of tinkering, or you can also get a modern 2meg chip ram upgrade that fit in the Agnus socket or an old style that tap the Gary for extra line.

 

Addition: Once you have a Fat Agus you can also get an ECS Denise and then you have essentially an A600 with a better keyboard.

[+OLD CS1]

IIRC, on the A500, 2MB in the trap door is not really worthwhile.  Only so much goes to ChipRAM, the rest is SlowRAM.  Plus, if you already have 1MB on the board with a 1MB Agnus, the expansion does nothing for you.  I expect the docs for the RAM expansion should explain all of this to you.

 

The nice thing about the BaseBoard (I had one loaded with 4MB) is that it maps memory to both ChipRAM and FastRAM.  The jumper and the Gary adapter is how it maps FastRAM.

[Tuxon86]

12 hours ago, OLD CS1 said:

IIRC, on the A500, 2MB in the trap door is not really worthwhile.  Only so much goes to ChipRAM, the rest is SlowRAM.  Plus, if you already have 1MB on the board with a 1MB Agnus, the expansion does nothing for you.  I expect the docs for the RAM expansion should explain all of this to you.

 

The nice thing about the BaseBoard (I had one loaded with 4MB) is that it maps memory to both ChipRAM and FastRAM.  The jumper and the Gary adapter is how it maps FastRAM.

You can get 2mb chipram on an A500 with this: https://icomp.de/shop-icomp/en/shop/product/ace2.html

I've one plus my 8mb fast ram/sd card ide adapter under my cpu. Only thing missing on my setup is the ECS Denise because I don't feel like paying $100 for a chip at the moment.

[+OLD CS1]

1 hour ago, Tuxon86 said:

You can get 2mb chipram on an A500 with this: https://icomp.de/shop-icomp/en/shop/product/ace2.html

I've one plus my 8mb fast ram/sd card ide adapter under my cpu. Only thing missing on my setup is the ECS Denise because I don't feel like paying $100 for a chip at the moment.

This is essentially a MegAChip with 2MB on-board with a Fatter Agnus, not a trap door expansion.  I have a few of the original MACs in systems.

 

I cannot recall exactly how much I paid for my Super Denise BITD... around $30, I think, from Grapevine with a test disk.

[Tuxon86]

1 minute ago, OLD CS1 said:

This is essentially a MegAChip with 2MB on-board with a Fatter Agnus, not a trap door expansion.  I have a few of the original MACs in systems.

 

I cannot recall exactly how much I paid for my Super Denise BITD... around $30, I think, from Grapevine with a test disk.

I checked on fleabay for the price, not really a good measure of the actual going price.

 

[+OLD CS1]

Just now, Tuxon86 said:

I checked on fleabay for the price, not really a good measure of the actual going price.

 

Oh, God, no.  Things are way, way too highly-priced on eBay.  But that is a whole other discussion.

[number6]

16 hours ago, OLD CS1 said:

IIRC, on the A500, 2MB in the trap door is not really worthwhile.  Only so much goes to ChipRAM, the rest is SlowRAM.  Plus, if you already have 1MB on the board with a 1MB Agnus, the expansion does nothing for you.  I expect the docs for the RAM expansion should explain all of this to you.

 

The nice thing about the BaseBoard (I had one loaded with 4MB) is that it maps memory to both ChipRAM and FastRAM.  The jumper and the Gary adapter is how it maps FastRAM.

hmm...I have the 2 mb baseboard as well, but it was the daughterboard that held the additional 4 mb with mine. There was also a PAL B ugrade chip. Baseboard also had no conflict with MegaMidget Racer. Yep, we over upgraded our A500s for sure. heh.

 

#6

[Tuxon86]

23 minutes ago, number6 said:

hmm...I have the 2 mb baseboard as well, but it was the daughterboard that held the additional 4 mb with mine. There was also a PAL B ugrade chip. Baseboard also had no conflict with MegaMidget Racer. Yep, we over upgraded our A500s for sure. heh.

 

#6

Amiga 500, the first "ricer" PC...

[number6]

9 minutes ago, Tuxon86 said:

Amiga 500, the first "ricer" PC...

Actually MegaMidget Racer did have one minor issue. To install above 3 Baseboard upgrades required use of "3" rizers. That, in turn meant the keyboard would not fit in the A500, so that required converting the keyboard into an external keyboard. By the time you added external SCSI, adapted power supply to handle these additions, DCTV, DCTV RGB unit etc....the desk vanished.

 

#6

[Tuxon86]

3 hours ago, number6 said:

Actually MegaMidget Racer did have one minor issue. To install above 3 Baseboard upgrades required use of "3" rizers. That, in turn meant the keyboard would not fit in the A500, so that required converting the keyboard into an external keyboard. By the time you added external SCSI, adapted power supply to handle these additions, DCTV, DCTV RGB unit etc....the desk vanished.

 

#6

Good candidate for an A1500 case.

[+OLD CS1]

For my BaseBoard, I had a piece of card paper screwed to the back of my keyboard.  The RAM chips on the bottom row of the expansion board were skewed by the keyboard pressing against them.  I wound up upgrading to an M-Tec 020 accelerator with 8MB RAM on-board, so I was able to eventually sell the BaseBoard.

[Appeelicious]

There is single good point. If you have 2 mb agnus and the right modification, you can make the trap door become your 2 mb of chip RAM. It's an edge case, but it is worth mentioning

[+OLD CS1]

2 hours ago, Appeelicious said:

There is single good point. If you have 2 mb agnus and the right modification, you can make the trap door become your 2 mb of chip RAM. It's an edge case, but it is worth mentioning

Right.  The original A501+ provides the extra 1mb for ChipRAM for an A500+.

[oracle_jedi]

58 minutes ago, OLD CS1 said:

Right.  The original A501+ provides the extra 1mb for ChipRAM for an A500+.

 

So I've seen online guides that show adding extra RAM chips to a Rev 6A board, and then modding JP2 and JP7 to give 1MB of Chip RAM.

 

And as I understand it, just modding JP7 would change the trapdoor RAM from Fast RAM to Chip RAM, although some guides say some older software that needs 1MB wont run in this config.

 

So...  is it possible to add extra RAM chips for 1MB of Chip RAM, and then keep the trapdoor RAM as Fast RAM, for a total of 1.5MB?   Is that an option?   Is Chip RAM and Fast occupying the same physical RAM addresses or are they different?

 

If you add the extra RAM chips to a Rev 6A board and DONT modify JP2/JP7, is that effectively the same as having the trap door RAM card present?   Right now I have two A500s and only one A501.  I probably do have those RAM chips somewhere in my box of spares.

 

[Koopa64]

Is any of this actually necessary for old Amiga games? From what I've seen, most games only want 1MB RAM of some variety or another, mainly Chip RAM.

 

Can one get by with a 512KB trapdoor ram board and play most retail games from the 80s?

[+OLD CS1]

@oracle_jedi  Been a long time since I fiddled with a lower-revision A500, so my memory may be rusty.  I recall my Rev 5 motherboard could only accept 512k on the board and another 512k via an A501 with the Fatter Agnus installed -- otherwise, it was limited to 512k.  My Rev 6 had 512k on the board with empty sockets for another 512k, and it was maxed-out whether you added the on-board ChipRAM or the A501.

 

No, I recall the trap door could not expand FastRAM (CPU RAM) without additional connections, such as the Gary adapter provided by the BaseBoard.  Otherwise, RAM not allocated to ChipRAM from the trap door went into a memory space referred to as "Slow RAM" or "ranger memory," located at $00c00000, which is on a buss shared between the custom chips and CPU, but unusable to the custom chips.

 

Here is an Amiga memory map to help explain. http://oscomp.hu/depot/amiga_memory_map.html

 

2 hours ago, Koopa64 said:

Is any of this actually necessary for old Amiga games? From what I've seen, most games only want 1MB RAM of some variety or another, mainly Chip RAM.

 

Can one get by with a 512KB trapdoor ram board and play most retail games from the 80s?

Pretty much nailed it.  The highest spec I recall seeing commercial non-AGA games require is 1MB ChipRAM (or total RAM.)  Some games need both ChipRAM and FastRAM.  As expansions and acceleration became more commonplace, you could see games requiring a couple of MB FastRAM in addition to ChipRAM.

 

Otherwise, most floppy games just need ChipRAM.

[oracle_jedi]

2 hours ago, Koopa64 said:

Is any of this actually necessary for old Amiga games? From what I've seen, most games only want 1MB RAM of some variety or another, mainly Chip RAM.

 

Can one get by with a 512KB trapdoor ram board and play most retail games from the 80s?

That's exactly the question, and my frustration.   In fact I think the Amiga hates me.  All of them.

 

I have; A500 Rev6 NTSC, A500 Rev6 PAL, A500 w/ Vampire 2, A1200 NTSC with internal CF card based HD and an ACA1221+ and an A1200 PAL stock no HD.  I also have an ACA500+ with CF card based HD.

 

And with all of that my success rate at running any random WHD or ADF game is 50/50 at best.  Is that normal?  With my Atari 1040ST and a Satan HD most things do run.  Maybe 8/10.

 

On the Amigas; NMI errors, insufficient ChipRAM, Insufficient memory, green screen (ACA500+), black screen, red screen (Rainbow Island), lock up, red-text-on-black-background illegal instruction errors and sometimes just title screens that refuse to respond to any input from keyboard or mouse.

 

Is it the Kickstart?  Is it an AGA/ECS/OCS issue?  Is it not enough RAM, RAM in wrong place, Chip RAM? Is it a PAL/NTSC timing issue?  Is the game fine but the hackers who plastered their intro over the front coded some dependency....

 

What is the most compatible Amiga config for playing casual games?

 

[+OLD CS1]

1 hour ago, oracle_jedi said:

What is the most compatible Amiga config for playing casual games?

The most compatible?  Bare-bones A500 Rev 6, NTSC or PAL depends upon what mix of games you want to play, an A501 RAM expansion for 1MB ChipRAM, and Kickstart 1.3.  Then, either the floppy drive or a floppy emulator.

 

I cannot help with the latter as I use either real floppy disks or an accelerated system with WHDLoad.

 

Everything else you mentioned, as you proposed, needs troubleshooting.  A system with an ACA500+ or a Vampire would be a higher-end and flexible system which would allow larger games and more convenience using WHDLoad, but you will need to work out the various issues.

[Tuxon86]

I love my A500, but I’d prefer an A2000 or an A1200. The first just to see all I could fit in its slots, and the second for the aga mode.

I may’ve missed my chance in the past. Now they’re priced out of my reach, even for a beaten up, partially working exemple.

[Koopa64]

I fail to see how WHDLoad is more convenient when to load games into your Workbench drive, you either need another Amiga already set up (preferably with internet access) or a virtual Amiga using UAE on a PC or Mac. If UAE is required, it ends up feeling really pointless doing all that work for the real Amiga when the virtual one is right there.

 

A Gotek floppy adapter sounds great, just put ADF files on a USB drive. Seems like hardly any games need Workbench to be loaded first anyway.

[+OLD CS1]

@Koopa64  WHDLoad is great for loading in your floppy-based games onto a hard drive, as well as running old games on an accelerated system or on Kickstart greater than 1.3.  For the most part it multi-tasks with Workbench, so I can just call up a game of Blood Money on my A4000D whenever I want without having to reconfigure.  I do not consider UAE -- why would that even be a requirement?

 

Internet may be preferable, but not required as you just need a way to get the WHDLoad programs onto the system.  Otherwise, yeah, see my statement on the most compatible configuration.

[+remowilliams]

Well with a suitable Amiga, WHDLoad and a menu system, or a complete packaged setup like Mega AGS - it sure doesn't get any more convenient to run tons of games effortlessly...

 

[Koopa64]

18 minutes ago, OLD CS1 said:

@Koopa64  WHDLoad is great for loading in your floppy-based games onto a hard drive, as well as running old games on an accelerated system or on Kickstart greater than 1.3.  For the most part it multi-tasks with Workbench, so I can just call up a game of Blood Money on my A4000D whenever I want without having to reconfigure.  I do not consider UAE -- why would that even be a requirement?

 

Internet may be preferable, but not required as you just need a way to get the WHDLoad programs onto the system.  Otherwise, yeah, see my statement on the most compatible configuration.

 

Ok, so how do you get games loaded into WHDLoad? Do you go online with your A4000D and get ADF files that way?

 

If one has nothing Amiga related besides an old Amiga, starting completely from scratch, you absolutely need a way to access an Amiga drive, Windows and Mac have nothing to deal with Fast File System and so on, that's where UAE is required.

 

@remowilliams:

 

Yes, it's convenient when finally set up... not convenient when starting from scratch.

Edited December 27, 2022 by Koopa64

[Tuxon86]

17 minutes ago, Koopa64 said:

 

Ok, so how do you get games loaded into WHDLoad? Do you go online with your A4000D and get ADF files that way?

 

If one has nothing Amiga related besides an old Amiga, starting completely from scratch, you absolutely need a way to access an Amiga drive, Windows and Mac have nothing to deal with Fast File System and so on, that's where UAE is required.

 

@remowilliams:

 

Yes, it's convenient when finally set up... not convenient when starting from scratch.

The main problem is that whdload wasn't really made for the A500 in mind. You need to upgrade the main ram, the chip ram and the cpu (to a 68010 so that you can quit a game without rebooting). In some case you also have to upgrade the roms. WHDLoad is really made for the 600 and up of the Amiga line unless you like to make hardware mods.