BillC Posted March 28, 2011 Share Posted March 28, 2011 Did the 32k cards (a al 400) work in the 800 as well? (ie have 32k with one card or 48k with 32k+16k) Depends who made it. The Axlon RAM-Cram 32K board could work in a 400 or in slot 2 of an 800, but not in slot 1 (because they did not follow Atari's scheme, as noted in the first post). The Intec 32K board could work in either slot 1 or 2 but not in a 400 (they didn't quite get it either). The Austin Franklin flyer claimed their 32K board worked in either slot 1 or 2 and in a 400 (maybe they got it, though I have never seen one to verify). I don't know about the Best 32K board. No 32K board could work by itself in the 800 because no slot has all the select lines S0, S1, S2, and S3 (without loopbacks or jumper wires). So, all the boards above required another RAM board in the other slot. So you're saying the RAM slot in the 400 is wired differently than the 1st RAM in the 800 since 32k boards will work in that without any other RAM board but not in the 800 without another one? That doesn't make much sense. Wouldn't they have used the same process for wiring up the RAM slots on both machines so as not to complicate production unnecessarily? They made it that way because the 800 would always ship with at least one RAM card, and most people at that time would want to keep as much as possible when upgrading since RAM was expensive back then, so they made slot 2 able to take the larger cards. At that time they didn't think anyone would want to have all the memory on a single board, chip density back then required multiple boards. Remember these computer started production in 1979, my first Atari 400 only came with 8K, received Christmas 1980. It was different with the 400 since the only way to upgrade the RAM is to replace the card, so they made the single slot able to take 32K cards. As it is the 48K and larger upgrades for the 400 require jumpers for the extra select lines to be installed. They also didn't expect these computers to still be in use 30+ years later, when multi-Gigahertz multi-core 64-bit CPUs/multi-Gigabyte RAM/multi-Terabyte HDDs are common. Quote Link to comment Share on other sites More sharing options...
ClausB Posted March 28, 2011 Author Share Posted March 28, 2011 (edited) No 32K board could work by itself in the 800 because no slot has all the select lines S0, S1, S2, and S3 (without loopbacks or jumper wires). So, all the boards above required another RAM board in the other slot. So you're saying the RAM slot in the 400 is wired differently than the 1st RAM in the 800 since 32k boards will work in that without any other RAM board but not in the 800 without another one? That doesn't make much sense. Wouldn't they have used the same process for wiring up the RAM slots on both machines so as not to complicate production unnecessarily? They made it that way because the 800 would always ship with at least one RAM card, and most people at that time would want to keep as much as possible when upgrading since RAM was expensive back then, so they made slot 2 able to take the larger cards. At that time they didn't think anyone would want to have all the memory on a single board, chip density back then required multiple boards. Remember these computer started production in 1979, my first Atari 400 only came with 8K, received Christmas 1980. It was different with the 400 since the only way to upgrade the RAM is to replace the card, so they made the single slot able to take 32K cards. As it is the 48K and larger upgrades for the 400 require jumpers for the extra select lines to be installed. The original point of this thread was to show how Atari went to great lengths to allow 8K and 16K boards in any order in the 800 and also to allow 32K in slot 1 or slot 2, if the board is wired correctly and there is a smaller board in the other slot. The 400's slot follows the same concept as far as a single slot can. It has S0, S1, S2, and S3, so it accepts 8K, 16K, or 32K without modification. Edited March 28, 2011 by ClausB Quote Link to comment Share on other sites More sharing options...
kool kitty89 Posted April 18, 2011 Share Posted April 18, 2011 both of those are Atari 48k upgrade boards... they have 64k chips as no one has made 48k chips, and its easier and cheaper (and space, power, etc...), to just use 48k of the 64k, then to have 24 16k chips, or 48 8k chips... sloopy. Hmm was that also the case with the Spectrum 48k in the early 80s? Also, that's all in the context of 1-bit wide DRAM chips (albeit 2-bits wouldn'd be any better). What about 16kx4-bit DRAMs? (where there never 4-bit wide DRAMs at 8 kB densities, even by the mid/late 80s? -they must have had 64kx4-bit DRAMs by the late 80s given the C64 switched to using dual 32 kB chips by that time, but maybe that was never pushed for lower densities) Even if 4-bit wide DRAM chips became available too late to be of use for the 800, they could have been useful for the 600XL's RAM expansion (at least if the 600XL had stayed in production longer) via 6 16kx4-bit chips rather than 8 64kx1-bit chips. 2-bit wide chips would have been useful for 32k onboard RAM or expansion boards (4 32kx2-bit chips), but not too much else. (if there WERE 2-bit chips available in 1983, it might have been smart to make the 600XL a 32k machine out of the box and making the expansion board cheaper/lower power as well -the price of 8kB densities had already dropped below 2kB chips by '83 -and with a rapidly widening gap- plus you'd save traces and board space with 4 chips rather than Also, it was previously implied that you're limited to multiples of 2 for DRAM densities, but it's really multiples of 4 most of the time (with few exceptions -often "half bad" chips rather than genuine 1/2 densities as well). The "normal" DRAM densities are always powers of 4 starting at 1 kbit (128 bytes) and going up from there. (4kbit, 16k, 64k, 256k, 1M, 4M, etc -4Mbit, of course being 512kB) Quote Link to comment Share on other sites More sharing options...
Rybags Posted April 18, 2011 Share Posted April 18, 2011 IIRC there were RAM chips that were "half disabled" in the early 1980s. e.g. a 4K chip fails testing but it's found that the fault only resides in one half, so the chip is packaged as a smaller size. Not sure how that'd work though, 6 bits row/column gives 4kbits, so maybe they use 1 less row or something. Quote Link to comment Share on other sites More sharing options...
BillC Posted April 18, 2011 Share Posted April 18, 2011 What about 16kx4-bit DRAMs? (where there never 4-bit wide DRAMs at 8 kB densities, even by the mid/late 80s? -they must have had 64kx4-bit DRAMs by the late 80s given the C64 switched to using dual 32 kB chips by that time, but maybe that was never pushed for lower densities) Even if 4-bit wide DRAM chips became available too late to be of use for the 800, they could have been useful for the 600XL's RAM expansion (at least if the 600XL had stayed in production longer) via 6 16kx4-bit chips rather than 8 64kx1-bit chips. The 600XL does use 2 4416(16kx4-bit) DRAMs for 16KB, and is easily upgraded internally to 64KB using 2 4464s(64kx4-bit) and some jumpers. Late production XE's use 4464 DRAM, 2 for 64KB on 65XE/800XE and 4 for 128KB on 130XE. Quote Link to comment Share on other sites More sharing options...
kool kitty89 Posted April 18, 2011 Share Posted April 18, 2011 (edited) IIRC there were RAM chips that were "half disabled" in the early 1980s. e.g. a 4K chip fails testing but it's found that the fault only resides in one half, so the chip is packaged as a smaller size. Not sure how that'd work though, 6 bits row/column gives 4kbits, so maybe they use 1 less row or something. Yes, the CoCo commonly used that early on, but those chips were only common up to the early 1980s and rapidly disappeared with improvements in yields. However, there were some custom densities available later on (I believe Sega used 32kx16-bit PSRAM chips for the later model MD/Genesis consoles -up to the early model 2 systems, they were using dual 32kx8-bit PSRAMs thouch), and apparently SDRAM was offered in 256 kB densities early on too (the 32x and Saturn use 128kx16-bit chips -Saturn has 256kx16 as well), but maybe that was related to yields on early SDRAM chips too. (we're talking 1993-95 here) What about 16kx4-bit DRAMs? (where there never 4-bit wide DRAMs at 8 kB densities, even by the mid/late 80s? -they must have had 64kx4-bit DRAMs by the late 80s given the C64 switched to using dual 32 kB chips by that time, but maybe that was never pushed for lower densities) Even if 4-bit wide DRAM chips became available too late to be of use for the 800, they could have been useful for the 600XL's RAM expansion (at least if the 600XL had stayed in production longer) via 6 16kx4-bit chips rather than 8 64kx1-bit chips. The 600XL does use 2 4416(16kx4-bit) DRAMs for 16KB, and is easily upgraded internally to 64KB using 2 4464s(64kx4-bit) and some jumpers. Late production XE's use 4464 DRAM, 2 for 64KB on 65XE/800XE and 4 for 128KB on 130XE. Thank you! That corrects the misinformation I received here: http://www.atariage.com/forums/topic/176524-7800-what-did-atari-wrong/page__st__150__p__2209704#entry2209704 2 8kB 16 pin DIP chips 4-bit wide DRAM? Didn't exist in 1984, or especially in 1983 when the 7800 was actually being designed. 16Kx4 would have been perfect for the consoles of the day. So it seems 16kx4-bit DRAMs became available by 1983, though probably not for most of 1982 (or at least not cost competitive with 16kx1-bit chips as in the 600 prototype and Atari 5200). That would also have meant significant cost reduction for the 5200 if Atari had invested in that. (a ton of potential to consolidate the 5200 -it should have been significantly cheaper than the Colecovision in the first place, but ended up rather sloppy overall -not just in terms of cost optimization, but that was one of the issues for sure -also one of the issues that could be completely solved after the fact too) Did the 1064XL module use 6 4416 DRAOM chips? Edited April 18, 2011 by kool kitty89 Quote Link to comment Share on other sites More sharing options...
Rybags Posted April 18, 2011 Share Posted April 18, 2011 (edited) According to the schematic I have, the 1064 has 8x4164s. Also, interestingly it uses 4 sequential feeds through an LS04 to accomplish the RAS->CAS delay. I think some 8K modules for the 800 used the "half" RAM chips. I remember reading an article in an old magazine which had instructions to replace the chips to double the size of the module. Edited April 18, 2011 by Rybags Quote Link to comment Share on other sites More sharing options...
sloopy Posted April 18, 2011 Share Posted April 18, 2011 the 1064 does use 8 4164's... and 16kx4bit devices were available by '82... just not cheap... you have to remember chip yield was a large factor in IC manufacturing, back then high loss was common (up to 50% on more complex IC's), so getting high density chips was a costly endevor, especially considering the issue of quantity a system would need... you also need to take into account the type of people they were expecting to sell to... they were expecting to sell the 600XL to someone who wanted a computer, they were expecting to sell to someone who wanted a game console but could be later expanded into a full computer, which often times never happened, they would just buy a new machine... add-ons werent made because of the fracturing of the market or line, it was because they wanted to make a whole new product. why would they sell you a $50 add-on with a 40% margin, when they could sell you a whole new product for $200 with the same (or even better) margin? why would atari want to sell you a 256k upgrade to your 800XL, when they could sell you a whole new 130XE? same with keyboard/mass storage for the 7800, why sell those things when you could be talked into buying a 800XL or even a 130XE? even tho the graphics and sound were more limited relatively, it was the ability to sell bigger profit items... simple business, ask any sales man, they want you to sell the big profit margin items over small margin, even if its something you dont want/need... sloopy. Quote Link to comment Share on other sites More sharing options...
stevem00 Posted April 21, 2011 Share Posted April 21, 2011 I've picked up a number of A800s with no RAM cards. Rather than buy a slew of 16K cards, does anybody have an idea of what jumpers would have to be added to an 800 mobo to use an A400 48K RAM expansion card? stevem Quote Link to comment Share on other sites More sharing options...
ClausB Posted April 21, 2011 Author Share Posted April 21, 2011 ... what jumpers would have to be added to an 800 mobo to use an A400 48K RAM expansion card? Depends. Which manufacturer's 48K board? Quote Link to comment Share on other sites More sharing options...
stevem00 Posted April 21, 2011 Share Posted April 21, 2011 ... what jumpers would have to be added to an 800 mobo to use an A400 48K RAM expansion card? Depends. Which manufacturer's 48K board? How can you tell? Quote Link to comment Share on other sites More sharing options...
BillC Posted April 21, 2011 Share Posted April 21, 2011 ... what jumpers would have to be added to an 800 mobo to use an A400 48K RAM expansion card? Depends. Which manufacturer's 48K board? How can you tell? Instructions for modifying a 16KB RAM card to 48/64K, and the jumper connections required for the 400, are available in the following thread. It should be relatively easy to work out where to connect the jumpers for use in an 800. http://www.atariage.com/forums/topic/109732-atari-400-48k-memory-upgrade/page__hl__400+memory Quote Link to comment Share on other sites More sharing options...
stevem00 Posted April 21, 2011 Share Posted April 21, 2011 I have the Atari 400 Expansion kit and the excellent instructions for adding jumpers to the 400 mobo, but it isn't clear to me what jumpers are involved for the 800. BTW: For a blast from the past, the following tag fell out of a package for a 16K card I received recently. stevem Quote Link to comment Share on other sites More sharing options...
ClausB Posted April 22, 2011 Author Share Posted April 22, 2011 (edited) Try these jumper connections on the motherboard RAM slots: Slot 2 pin U to Slot 1 pin S Slot 2 pin S to Slot 1 pin P Slot 2 pin P to Slot 1 pin R Slot 2 pin M to Slot 1 pin N Then plug it into RAM Slot 1 and try it. I don't have one to test, but I have the PDF manual and I think this should work. Remember that the pin-lettering scheme skips G, I, O, and Q. Use the 400 motherboard photo in the manual as a guide. The 800's numbering/lettering is the same. Edited April 22, 2011 by ClausB Quote Link to comment Share on other sites More sharing options...
stevem00 Posted April 23, 2011 Share Posted April 23, 2011 Here is a diagram showing the pins to be connected to use a 48K board in RAM slot 1 on an Atari 800. stevem Quote Link to comment Share on other sites More sharing options...
ClausB Posted April 23, 2011 Author Share Posted April 23, 2011 Good work! Quote Link to comment Share on other sites More sharing options...
stevem00 Posted April 23, 2011 Share Posted April 23, 2011 Good work! Thanks so much for the pin assignments. stevem Quote Link to comment Share on other sites More sharing options...
fibrewire Posted April 23, 2011 Share Posted April 23, 2011 *** FREE *** Accepting PM's for a NIB 48K Expansion for Atari 400. Reserved for those who don't have one already. Limit one per customer. Free shipping inside continental United States EDIT: all new-in-box 48K boards have been spoken for. Enjoy! Quote Link to comment Share on other sites More sharing options...
fibrewire Posted April 24, 2011 Share Posted April 24, 2011 Will 'Slot 3' mods still work after the Atari 800 has been hardwired for the 48K board? Quote Link to comment Share on other sites More sharing options...
ClausB Posted April 24, 2011 Author Share Posted April 24, 2011 Will 'Slot 3' mods still work after the Atari 800 has been hardwired for the 48K board? Which mods? RAM boards won't work in Slot 3 afterward. I/O devices such as 80-column boards should still work. Quote Link to comment Share on other sites More sharing options...
Greg I Posted June 21, 2011 Share Posted June 21, 2011 Has anyone ever heard of an 800 256K RAM upgrade card made by Crystal Computer Products? I'm a long time Atarian (got my first 800 in 1981) and I picked up an 800 on ebay that has this card in the following configuration: a standard 16K card in memory slot 1, the 256K card in slot 2 and a 32K RAMCRAM in slot 3. I do not think the 256K card is Axlon compatible (my Happy Drive software doesn't recognize it), however, word processing and other software does recognize the additional memory. The 256K card is dated 1986. In all my experience, I can't recall this manufacturer and web searches yield nothing. Quote Link to comment Share on other sites More sharing options...
fibrewire Posted June 21, 2011 Share Posted June 21, 2011 Which mods? RAM boards won't work in Slot 3 afterward. I/O devices such as 80-column boards should still work. I would like to use Bit 3 in slot 3, Axlon 128 in slot 2, and a modded Atari 48K card in slot 1. Quote Link to comment Share on other sites More sharing options...
ClausB Posted June 21, 2011 Author Share Posted June 21, 2011 I would like to use Bit 3 in slot 3, Axlon 128 in slot 2, and a modded Atari 48K card in slot 1. With a modded motherboard as posted above, the Bit 3 should work, but not the Axlon 128K. I could come up with a different mod for the 48K board that would work with the Axlon. Quote Link to comment Share on other sites More sharing options...
ClausB Posted June 21, 2011 Author Share Posted June 21, 2011 Has anyone ever heard of an 800 256K RAM upgrade card made by Crystal Computer Products? I'm a long time Atarian (got my first 800 in 1981) and I picked up an 800 on ebay that has this card in the following configuration: a standard 16K card in memory slot 1, the 256K card in slot 2 and a 32K RAMCRAM in slot 3. I do not think the 256K card is Axlon compatible (my Happy Drive software doesn't recognize it), however, word processing and other software does recognize the additional memory. The 256K card is dated 1986. In all my experience, I can't recall this manufacturer and web searches yield nothing. Never, but it would be interesting to see it. Could you post sharp photos of both sides of the board? Quote Link to comment Share on other sites More sharing options...
Greg I Posted June 22, 2011 Share Posted June 22, 2011 Has anyone ever heard of an 800 256K RAM upgrade card made by Crystal Computer Products? I'm a long time Atarian (got my first 800 in 1981) and I picked up an 800 on ebay that has this card in the following configuration: a standard 16K card in memory slot 1, the 256K card in slot 2 and a 32K RAMCRAM in slot 3. I do not think the 256K card is Axlon compatible (my Happy Drive software doesn't recognize it), however, word processing and other software does recognize the additional memory. The 256K card is dated 1986. In all my experience, I can't recall this manufacturer and web searches yield nothing. Never, but it would be interesting to see it. Could you post sharp photos of both sides of the board? ClausB - Per your request. Quote Link to comment Share on other sites More sharing options...
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