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Apple IIe memory chips

I am posting in this forum to see if anyone here with an non working apple iie or parts would happen to have a few extra memory chips, aka 16 pin dip memory chips from one of their memory expansion boards? The chips are also the same used on the original mac 128k and I have a bad chip I need to replace. I would appreciate anyone who would be willing to help me. The compatible memory chips ake called 64k chips and the following part numbers are various manufactures who make them:

D4164C-2 NEC

D4164C-15

HYB4164P2BD Hitachi

KM4164B-15 Samsung

M3764A-15 OKI

M5K4164AP-15 Mitsubishi

MB8264-15 Fairchild

MCM4164BP15 Motorola

MCM6665BP20 Motorola

MK4564N-20 Mostek

MT4264-25 Micron

TMS4164-15NL TI

TMS4164-20NL

Again I thank you for any help you may provide,

Peter

 
sorry to bring this thread back up….

but he has a great cross reference table there.

so the Apple IIc and the Macintosh 128k used the same memory chips?

Any other Mac or Apple products use this ram?

How about the IIGS ram card?

 
Good info! I have more than a few Apple II parts laying around - and a couple 128k boards I would like to bring back to 128k, even if there is no Apple logo on the RAM.

 
So far as I know the chips used in the Apple IIe/c and Mac 128k are completely bog-standard 4164s so you shouldn't really need a cross-reference table; IE, searching for "4164 DRAM" should net you a compatible 64kbitx1 part, the only thing that should matter beyond that is the speed rating. A 4164-15 has 150ns access time, while a -12 is 120, etc. As long as the part you pick is as fast or faster (IE, the -number is the same or smaller) it should work. Perhaps people that have repaired these systems have experienced (reproducible?) incompatibility issues with particular vendors but they're supposed to be a standard part.

(Note that for some of the oddball part numbers that don't include "4164" it's still usually not that hard to find a replacement; the better/more knowledgeable vendors online are pretty good at putting together compatibility matrices.)

The same chips were used in practically every "64k" home computer made in the early-mid-80s. Some late models, like the last Commodore 64s, Tandy CoCo2s, and the Apple IIc Plus, switched to the 4464 (also confusingly called the 41464), which is a 256kbit, 64kx4 part. There's little danger of confusing the two because the 4464 has 18 pins to the 4164's 16. These parts are the same density as the 41256 256kx1 chips used in many mid-80s 16 bit computers (like most PC clones with 512k or more of RAM, Amigas, Atari STs, and, yes, the Fat Mac) but likewise have a different pinout, as the 41256 also has 16 pins. (According to the C64 Wiki if you're really desperate you can sub a 41256 for a 4164 by adding a jumper wire.) In any case, 4164s are still readily available. Even Jameco still has them for 99 cents each. The chips that are *starting* to get hard to find are the 4116 16k chips that were used in the Apple II plus and earlier. That said, Jameco claims to have those too. (And it's also possible to sub a 4164, although the result looks sort of ugly unless you modify the motherboard instead of using jumper wires. One of my PETs has the 4116s replaced with 4164s. The best reason for doing this is to reduce load on the power supply; the 5+ volt only silicon process used in the 4164s is a considerable improvement over the triple-voltage 4116 and the chips draw less than 1/4th the total current. And that's discounting the loss in the regulators.)

Again, these are *very standard* parts, made in the millions. About the only semi-common 80's DRAM chip I've glossed over is the 16kx4 equivalent of the 4464, the 4(1)416. You might run across those in the last 16k/32k computers that made it out the door. There's also a semi-rare 16kx1 RAM variant, the 4516, that's mostly the same as the 4116 but only uses a single 5v supply. (Which also makes it essentially a 16k version of a 4164) I don't know of any Apple product that uses either of these chips.

(Well, okay, by the later 80's there were also the 1Mb dense chips like the 44256 and its 1Mbx1 counterpart, but I think Apple had pretty much stopped using DIP-package RAM in computers by the time these became common so they seem a little off-topic for this thread. You will find those in PC-ATs, etc, and possibly some Apple IIe/GS memory cards.)

 
thanks G!!!!

So:

Apple IIe

Apple IIc (Early - Mid production) — late models with 4464 chips, do not work with 4164's

Macintosh 128k

C 64 - (Early - Mid production) — late models with 4464 chips, do not work with 4164's

C 128 - (Early - Mid production) — late models with 4464 chips, do not work with 4164's

C PET (Replaces 4116's)

COCO 2 - (Early - Mid production) — late models with 4464 chips, do not work with 4164's

Also--

4164"s were:

The same chips were used in practically every "64k" home computer made in the early-mid-80s
So in most cases you can mod the 4164 to be used where 4116 is, — will reduce load on the psu as well!

What is the mod if you don't mind me asking sir?

 
More info: A quick google turned up this. Crazy detailed with some compatibility charts linked. It looks like the most common problem you might run into when swapping manufactures is if your device *requires* a 128 cycle refresh; 256 cycle chips won't work. (The reverse should be okay, however.) If there's any question and you don't have sufficiently detailed service documentation/schematics with the information Googling for the datasheet of the chips you're replacing should tell you whether a 256 cycle version will work or not.

There are one or two really oddball devices, like a couple Motorola versions that offer a built-in refresh counter triggered by pin #1, but it's not likely anything Apple uses them.

Apple IIe
I don't know offhand, but I wonder if the later "platinum" IIes also use 4(1)464s. I also think there's a really-low-chip-count version of the "enhanced 80 column" card that must use them.

So in most cases you can mod the 4164 to be used where 4116 is, — will reduce load on the psu as well! What is the mod if you don't mind me asking sir?
The mod is mentioned on that C64 wiki page, but: here's a link discussing how to make an adapter for replacing a single chip (You can also do this by just bending up the affected pins so they don't go into the socket and soldering appropriate jumpers to them), while here's an example of modifying a device motherboard to replace a whole bank. Should probably stress that you likely *don't* want to do the latter to something that might have collector value, like an original Apple II board.

(The modifications to the PET I have were done by the guy I originally got it for and later decided he didn't have room in his life for it, and are beautifully done. Since the +12/-5v regulators on the Dynamic Board PETs aren't used for anything else he desoldered them, insulated their pins with shrink tubing, and glued them back to the board. The rest of the mod is two *very well hidden* jumper wires so it looks stock, only looking at the chip labels gives it away. But, again, a Dynamic PET motherboard is much, much cheaper than an Apple ][ board these days.

Also, weird triva: The chips that were replaced were actually "4108s", a *really* oddball device that electrically is the same as a 4116 but ignores A13, thereby only providing 8k of RAM. Rumor has it that these are actually 4116 dies with one bank disabled, either because it was bad or just completely for marketing purposes. I don't think anyone used them but Commodore, and Commodore was somewhat infamous when it came to intentionally crippling things in order to upsell the consumer. All common versions of the PET all the way back to the static RAM versions had two memory banks, and when Commodore discovered that customers were buying the lower memory models and soldering in the sockets to populate the second bank themselves they started literally sawing that part of the motherboard out on the cheaper models.)

 
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