Macintosh 128K Teardown

Teardown

Teardown

Teardowns provide a look inside a device and should not be used as disassembly instructions.

Featured Guide

Featured Guide

This guide has been found to be exceptionally cool by the iFixit staff.

Join us as we live the time-traveler's dream—the deep, lucid, Orwellian vision of hope, fear, and nostalgia that is 1984. Just in time for its 30th anniversary, we laid hands on an '84 original: the Macintosh 128K. And, you guessed it—we're tearing it down like it's the Berlin Wall.

Today's blast from the past is brought to you with some awesome help from Cult of Mac and The Vintage Mac Museum. Cult of Mac will have us note that no vintage Macinti were harmed in the making of this guide. Our 128K had already passed beyond the veil before its noble sacrifice.

Fire up the flux capacitors and find our Facebook, track our timely Tweets, and get a dose of nostalgia from our filter-friendly Instagram.

Want some sweet Mac 128K wallpapers? Come get some!

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Edit Step 1 Macintosh 128K Teardown  ¶ 

  • The original Mac retailed for $2,495—that's $5,594.11 in today's dollars. So what did you get for all that coin?

    • 8 MHz Motorola 68000 processor

    • 128 KB DRAM

    • 9" black-and-white CRT display running at 512 x 342 (72 dpi)

    • 400 KB total storage via a single-sided 3.5-inch floppy disk drive

    • Single-button mouse and hefty keyboard

  • Inflation notwithstanding, this treasure of the '80s didn’t cost us a cent. A big thanks to our friends at the Vintage Mac Museum for lending us this Mac, and to Cult of Mac for injecting some extra '80s flavor into the teardown!

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Edit Step 2  ¶ 

  • Before we crack open this time capsule (no, not these Time Capsules), let's take a moment to see just how far we've come in three decades.

  • First up, displays. 1984's Mac 128K featured a 9" CRT with 512 x 342 resolution and support for two colors: black, and white. On the right, our lovely comparison Late 2013 iMac has a 21.5" 1920 x 1080 pixel display with millions of colors. Oh, and the original iPhone had a 480 × 320 pixel screen at 163 ppi.

  • As Apple works to popularize Thunderbolt, a 20 Gb/s IO interface, let's reflect back on the high-speed Serial port, sporting speeds measured in thousands of bps, rather than billions.

  • But hey, at least the AC plug is the same.

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Edit Step 3  ¶ 

  • Thirty years of progress yields some impressive changes to input peripherals. Keyboards and mice are now wireless, thinner, and comprised mainly of sturdy, non-yellow metal.

  • And we now have arrow keys! In typical Apple fashion, they ditched the arrows on the original Mac to force people to use the mouse, a strange new accessory at the time.

    • Cult of Mac adds: This trend-setting streak continued. Apple jettisoned SCSI and serial ports with the release of the first iMac in 1998, hastening the acceptance of USB. Plus ça change, plus c'est pareil.

  • Here's a side-by-side comparison of a single-button voice command peripheral and a magic-based, gesture-capable, wireless input device.

    • Okay, technically that boxy one is an Apple Mouse II, Model Number M0100. It utilizes a D-subminiature serial connector (DE-9 to be exact). The spacey egg is a Magic Mouse.

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Edit Step 4  ¶ 

  • Now that's a model number: Macintosh Model M0001. (Apple built in just a teensy bit of headroom for future models.)

  • These early labels are sad tidings— even in Apple's younger, wilder days they didn't want people to service their own gadgets.

    • This is it, the beginning of an exciting challenge—to fight for the right to repair!

  • That FCC label means business: if you're going to tinker with your Mac, you run the risk of local radio interference. (We're guessing Pandora wasn't a viable alternative in 1984.)

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Edit Step 5  ¶ 

  • It makes no difference to our Pro Tech Toolkit when this Mac was manufactured—it's packed with all the tools you need for the repairs of yesterday, today, and tomorrow.

  • Our flex extension takes on the deeply recessed T15 screws in the case.

  • True to form, Apple hid a screw; this time, it's under the clock battery door. No fuss for us, it's out and we're spudgering into history.

  • Cult of Mac adds: Fortunately these early Macs were not glued together—and even had a user-replaceable battery.

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Edit Step 6  ¶ 

  • We deliver and open the vault; we're only slightly disappointed at the lack of a cool pneumatic sound effects.

  • The entire machine slides out of the back case, revealing the power supply, CRT display, 3.5-inch floppy drive, and hiding beneath it all, the logic board.

  • Molded into the inside rear plastic casing are runes of technology past the autographs of Steven Jobs, Woz, Bill Atkinson, Andy Hertzfeld, Bruce Horn, Jef Raskin and the rest of the historic team.

  • Cult of Mac adds: Real artists sign their work.

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Edit Step 7  ¶ 

  • Now that we're in authorized-service-personnel-only land, we found a few calibration potentiometers for fine-tuning the display.

  • Ye olde CRTs were a mixed bag for repair purposes—easier to access than today's tight-fitting flat panel displays, but boy were they dangerous if mishandled. Those high voltage warnings are no joke.

  • Present, meet your past, face to face. And if you're both here in 30 years, maybe you'll meet the future.

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Edit Step 8  ¶ 

  • Between the CRT and the capacitors, disconnecting this power supply sort of feels like disarming a bomb.

  • Apple did their best to keep average users out of the Macintosh, using Torx screws on the exterior. But once you're inside, it's a fun mix of screw types, including Phillips and flathead. Time to pull out our favorite roll of fixed-handle drivers, the Pro Tech Screwdriver Set.

  • Cult of Mac adds: We'd still rather disassemble a 128K Mac than an iMac any day!

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Edit Step 9  ¶ 

  • To the tune of Mission Impossible, we quickly and safely remove the power supply. No electrocuted technical writers... today.

  • This 60-watt power supply is Apple Part number 630-0102.

    • We think 60 watts peak is pretty dang impressive for an entire computer and CRT display.

  • Our comparison iMac features a 186 watt power supply, that fits onto a considerably smaller circuit board than the 128K's.

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Edit Step 10  ¶ 

  • And the award for most noticeable technological advancement goes to: Mac displays. This enormous old CRT is a far cry from the graphics offered by today's ultra-thin Retina displays.

  • Bulky, heavy, and full of lead, these old-school electron guns in vacuum tubes and their deflection coils were all the rage in the '80s. Totally tubular!

  • Cult of Mac adds: The original Macintosh display was only 1-bit black & white, yet ushered in the revolutionary era of WYSIWYG (What You See Is What You Get) graphics and desktop publishing.

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Edit Step 11  ¶ 

  • Even 30 years ago, Apple had a thing for tidy packaging. With just a little coaxing, the logic board slides neatly out of its tray.

  • There's no active cooling on this daddy Mac. The Motorola 68000 has a little breathing room, but nothing more.

  • Cult of Mac adds: The 68k also powered the Lisa, Apple's predecessor to the Macintosh.

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Edit Step 12  ¶ 

  • Notable ICs on the Mac 128K logic board:

    • Motorola MC68000G8 Microprocessor

    • Fairchild Semiconductor 74LS393 Video Counter

    • Micron 4264 64 kb RAM (64 kb x 16 chips = 1024 kb, or 128 KB)

      • The namesake for the 128K was this non-upgradable array of RAM. Anticipating that customers would want more power, Apple engineers secretly designed the logic board to facilitate manufacturing a 512 KB version, which was released only nine months later.

    • Simtek C19728 and C19729 32 KB ROM (32 KB x 2 ICs = 64 KB)

    • Simtek 344-0041-A "Integrated Woz Machine" Disk Controller

    • Zilog Z8530PS Serial Communications Controller

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Edit Step 13  ¶ 

  • What do we have here? A Sony…printing press? Planer? Turbo Encabulator?

  • We know you guessed right; it's a 3.5-inch floppy disk again leading the charge to new technology, leaving the old 5.25-inch drives in the past.

  • Cult of Mac adds: The Macintosh almost shipped with the same 5.25-inch "Twiggy" floppy disk drive the early Lisa used, but the Sony 3.5-inch drive earned its job in a rather entertaining fashion.

Edit Step 14  ¶ 

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Edit Step 15  ¶ 

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Edit Step 16  ¶ 

  • Now for some mouse dissection! Don't worry—this will be much more humane than what went down in high school biology class.

  • We pop out the eye ball with a quick twist.

  • Opened up, we find plenty of plastic viscera, two quadrature encoders and a few resistors. Surprisingly, that's about all we find.

  • This simplified design decreased costs and improved reliability by moving the complex circuitry out of the mouse and into the desktop, paving the way for cheap desktop mice for years to come.

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Edit Step 17  ¶ 

  • Macintosh 128K Repairability Score 7 out of 10 (10 is easiest to repair).

  • Once you’re inside, it’s simple and straightforward to replace any of the main components: floppy drive, power supply, logic board, or CRT display.

  • No adhesive anywhere.

  • User-replaceable clock battery.

  • Limited upgradability: The RAM is soldered to the logic board and can’t be replaced, and there’s no slot/port to add an internal drive. However, you can expand storage via an optional external floppy drive.

  • The case is fairly difficult to open, with deeply recessed screws and a tight panel fit.

  • There are some dangerous high voltages on both the power supply and the CRT that make repair potentially hazardous.

Required Tools

Spudger

$2.95 · 50+ In stock

Phillips #1 Screwdriver

$5.95 · 50+ In stock

6-in-1 Screwdriver

$4.95 · 6 In stock

T15 Torx Screwdriver

$6.95 · 15 In stock

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Universal Drive Adapter

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Comments Comments are onturn off

I can remember upgrading a Mac - kinda scary since new it cost me like $3,000! All went well and I did a couple of more for friends.

The Lisa was much easier to work with - the stuff just slide out like a tray. Had one that had been converted by Sun Computer in UT. I was the envy of all my friends with that machine - 'big' screen!

Richard Stevens, · Reply

I didn't see anything about discharging the CRT tube. And important step if you are working on such old technology.

Sam Weiss, · Reply

The RAM 'could' be replaced. I know, because I can remember upgrading my 128k machine to 512k on my kitchen table. I wouldn't recommend anyone try it because it's a lot of chips to unsolder.

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thuysearching, · Reply

Not true -- the serial port was RS-422, supporting much faster speeds

Joel Finkle, · Reply

RS-422 was introduced with the Macintosh Plus. It was not on the Mac 128 or Mac 512.

Tom Schmidt, · Reply

Incorrect - RS422 was there from the beginning - perhaps you are thinking of the DIN-style ports, which did indeed come in with the Mac Plus.

JohnC,

No, JohnC is correct.

MCA,

You're typing: "The quick brown fox jumps over the lazy dog"

Chris Reites, · Reply

As a 128K Mac owner from 1984, I can confirm that it had two 9-pin RS422 ports from the very beginning.

Ted T, · Reply

I pulled the storage box containing my old documentation for the Mac 128K and Mac 512k, and they confirm that the serial ports were RS422. The Mac 128k in the garage also with the keyboard, now if I can just find the mouse...

John, · Reply

Hey, you forgot to include discharging the high voltage cap!

Fred Torres, · Reply

My neighbor Fred, of Fred's Retort, took apart my 128 to upgrade it to 512K! With an external floppy disk, I was in Hog Heaven!

Dave, · Reply

What? No case cracker or CRT discharge tool? Those were essential tools for cracking open a classic Mac back in the day. Especially the discharge tool, used to prevent you from finding out why they call the black box at the end of the anode lead to the CRT a 'flyback' transformer.

http://www.pcmag.com/encyclopedia/term/3...

johnhutchens, · Reply

That power supply board wasn't the same design as the first 128k Mac boards. the first design had a tin shield on the entire inside edge of the power supply board to keep the board from flexing. The first design flyback transformers were about 1/2 the size as the one in the picture. I have soldered probably 1000 Mac 128,512 and Plus power supply boards after replacing the flyback transformer and all of the caps as the ones Apple used were not long life rated and failed frequently in the early macs

derwurst, · Reply

The RS-422 chip had support for two ports, and would also drive RS-232 (which is unbalanced, whereas RS-422 is balanced). But Apple "stole" one of the control signals, making it a bit hard to work with standard modems of the day. You needed a hacked cable that worked around the issue (the missing one was RTS/CTS, I think).

And what was the missing signal used for? Why, that was where the mouse signal went - one port had the X-axis, the other one had the Y-axis. These were hardware interrupts so mouse tracking was very good.

vpndev, · Reply

Back in the day, "No user-serviceable parts inside" was a warning to older people that this was not a vacuum-tube device, and if it stopped working, you couldn't simply pop it open, pull the tube, and take it down to the drugstore's tube tester.

Mark, · Reply

Made in USA, now those were the days!

Clayton Fraga, · Reply

During POST it would sit there with a totally gray screen.....

But the mouse cursor still worked beautifully.

No driver...no OS loaded...the mouse just worked.

cns, · Reply

Simply backing out the 2 recessed screws about half way and then pinging the handle of the driver is the easiest way to "crack" the case open

egrau, · Reply

By the time the Mac Plus came out with user-replaceable SIMMs, vendors like TechWorks were bundling the a cheap Torx T15 wrench with your RAM. Also, anybody remember Larry Pina's Macintosh Repair & Upgrade Secrets? Man, I had to resolder plenty of cold solder joints on analog boards. Such a great feeling getting those machines running again.

Darryl, · Reply

A couple of things I remember: If you went to Home Depot, you could find a clamp with a thin plate ends that would fit in the groove around the back case, and all you had to do was squeeze the clamp (i.e. open the clamp) and glide it around the groove until the case popped open. Much easier than trying to use a spudger (or, like many of us, marring the case with a screwdriver). On the analog board, the 4 pin molex plug was the frequent overheating spot. It drove the high voltage into the CRT and the heat would melt the solder and subsequent cooling would cause a cold solder joint, which meant your video would go in and out, and whacking it on the side sometimes restored it.

owen, · Reply

One point to remember when disassembling a compact Mac: If you've installed the "Reset/programmer's buttons" over the vents at the bottom side back corner, you should pop them out before removing the case back. Otherwise, they'd tend to snag on the motherboard back plate. The buttons provided a way to reset the Mac without having to turn it off. There was also a NMI (non-maskable interrupt) button that could be useful for programmers (like a hardware ctrl-C to break into a hung program).

cityzen, · Reply

We included an upholstered desk chair in our teardown/upgrade tools for classic Macs: at least the first time you cracked the case of one. Take out the screws, hold the Mac screen down over the chair, and shake. You could also buy a special Mac cracking tool that looked like a cross between a pair of pliers and a door hinge.

Matt Mitchell, · Reply

Hey!!! You have to discharge the CRT! 1,500 Volts!!!. This is a big deal!

Also, after discharging the CRT, you want to pull the CRT socket cable (That white disc) off of the CRT because if you bump it, you'll snap off a bit of glass on the end of the CRT and that will be all for that CRT.

scottrlindsey, · Reply

I can attest to this. I snapped that bit of glass off a Mac Plus while the customer was waiting for a RAM upgradge. Doh.

Kevin Becker, · Reply

The board on the right is more than just the power supply: it's called the "Analog Board" and includes a fair amount of the video circuitry (don't remember if there's any audio stuff on there)

Joel Finkle, · Reply

That's not just the power supply -- it's the high voltage, deflection, and video drive circuitry for the CRT.

(...and audio amp, and speaker...)

Mark Spaeth, · Reply

The good news is that if you could take a battery from one of Apple's newer laptops (say, perhaps the last Macbook with a user-replaceable battery), wire it to the Macintosh, and get as much battery life as the laptop. Or perhaps much more since you couldn't actually use the old computer for much.

JM Palacios, · Reply

I have the common components (mostly caps) and a flyback tranformer, repair kit for a mac plus analog board still on hand. Use to repair these all the time.

egrau, · Reply

It's probably a good place to point out that the 128, 512, and Plus all shipped with no fans. All part of Steve Job's obsession with silent machines no matter how it harmed the hardware. There were many ways available to get Fans into the case. Kensington had a device that slid into the handle that was both power supply and case fan. Some of the various interior upgrade cards came with little internal case fans.

Jenevieve DeFer, · Reply

Don't forget, the m68k was in the first Palm PDAs! (For roughly a good decade, too!)

Donald Kirker, · Reply

Been awhile since I checked the specs, but I'm pretty sure my TI-89 has more RAM and power than this Mac!

JM Palacios, · Reply

You wrote, "Even 30 years ago, Apple had a thing for tidy packaging." While that's true, Apple's tidy packaging dates back at least to the Apple II. It had a compact (for its day) switching power supply, the motherboard layout was super clean (the Apple I mobo also had a neat layout), and don't forget the sleek plastic case.

John M, · Reply

In fact, hobbyists and renegade repair shops would field-upgrade 128K machines to 512K by piggybacking additional RAM atop the existing chips.

Joel Finkle, · Reply

Yup! A friend of mine (a former Cray field tech!) did that to my 128, giving me a cheap double-your-RAM upgrade!

Dmitri Fetisov, · Reply

Those chips are Synertek, not Simtek.

http://www.datasheetarchive.com/integrat...

Mark Spaeth, · Reply

I had a floor model which I believe was first week's production. In Jan 1985, a RAM upgrade cost ~$750 but by December, that had fallen to $75--if you wanted to solder it in yourself. I got mine from MacMemory--and I got a long Torx screwdriver from them also. I snipped off the old ram and sucked out the old solder. I had the option of soldering in chip holders or soldering the RAM in directly, and I chose to do it directly--it had to be fast and precise because the circuit board was four layers thick and you couldn't overheat the chips. You have no idea what a wonderful feeling it was when I turned it on, a smiley face appeared and it went dong!

Clyde Kahrl, · Reply

What the article doesn't say is who the secret of upgradablity of the MAC motherboard was for (who they had to keep it secret from), Steve Jobs. He forbade them from making the motherboard upgradable. They had the last laugh though. The row of platethroughs next to the processor can have a small board soldered into it with one IC on it. A 74S158 if I remember. You could then unsolder the 64K chips and put in 256k chips. I remember doing this to a hackintosh I made way back in 1986.

This lack of upgradablity/reparablity pervaded almost everything Jobs built. I think he was offended by the idea that anyone would want expand (this would mean they were not adequate) or alter his perfect creations.

Walter Peterson, · Reply

Re: Mac 512K upgrades. At the time I worked for a semiconductor manufacturer so getting the necessary 74S157 and 16 ea 256Kx1 DRAMs was fairly easy. Finding the correct Torx driver was the bigger challenge.

Friends would bring their 128K Macs over and in two hours had a 512K Mac ... and I had $200 in my pocket. Big money back in 1984!

Phil Wood, · Reply

I didn't own a mac 128 but I did have a couple of Macintosh Plus machines. When I opened one up, I was driven to ask why it was called "Plus" rather than "Minus." Because it was minus a disk controller, minus video hardware, minus anything but the simplest audio hardware, minus any kind of expansion bus other than SCSI. All this "hardware" was actually emlulated in software at boot time by the CPU.

While this is quite a tribute to the abilities of the 68000 processor, the task of creating and maintaining all this phantom hardware meant there wasn't much left for actually doing work.

I had to wonder why this machine cost so much when it had so little inside it. This, together with the intentional lack of upgradeability, epitomises the Jobs world view which influenced everything Apple did, even up to today. The amazing thing to me is that so many people seem to be ok with this.

freddyzdead, · Reply

And a box of 10 of these retailed for $50, if you could even find them in the early days.

Joel Finkle, · Reply

They were extremely expensive. Fortunately, HP were using the same drives in some of their systems. I was able to persuade a friend who worked at HP the buy a case of floppy disks (10 boxes, each box containing 10 floppies) at the employee discount price of only $290.

John,

You can actually see that the opening in the front of the metal frame, through which the little 3.5" drive pokes, is designed for the full width 5.25" Twiggy floppy mechanism. Strangely this extra wide opening in the frame survived several original Mac redesigns, and was present in the SE series, and the Classic series of compact Macs for almost 10 years.

MinerAl, · Reply

The quick brown fox jumps over the lazy dog.

vwlou89, · Reply

You got it! Congrats, vwlou89, we'll get your prize out to you ASAP :D

Andrew Optimus Goldberg,

The Quick Brown Fox Jumps Over the Lazy Dog

Ben Chernicoff, · Reply

Jackdaws love my big sphinx of quartz!

Dmitri Fetisov, · Reply

In the video you guys are typing: the quick brown fox jumps over the lazy dog

dave, · Reply

Thank you for the video and Audio. Music to my ears!

chuckmcmillen, · Reply

Does anyone have an extra keyboard cable or could you lend me yours, so I can scan it and make a 3D copy of the jacks. I need to get my old Mac up and running again (@vassko)

Vassil Mladjov, · Reply

I have a good supply of brand new Mac 128K-Plus keyboard cables. But they are Platinum in color, for the later version of the Plus model.

Raymond Flowers,

You can crimp your own; just crimp one of the standard RJ9 connectors upside down from the other, producing a "straight through" cable.

Tom Spindler,

The keyboard key-switches were not that hard. Apple Service taught key switch replacement as part of Apple //e certification.

chuckmcmillen, · Reply

A third party offered a hard drive that mounted internally, using a clip atop the CPU.

Joel Finkle, · Reply

You're thinking of the SCSI interface upgrade. It clipped over the CPU and a ribbon cable was snaked out through the battery door. As far as installing an internal drive, you had to remember that it would be a while before 3.5" HDs would even be available, and that they were initially the same height as 5.25" 1/2-height drives (full height being about 3.25").

cityzen,

Ah, the Hyperdrive: http://www.flickr.com/search/?q=hyperdri...

I was thinking of something like the Dove MacSnap: http://www.vintagemacworld.com/macsnap.h...

The Hyperdrive was pretty rare & expensive, whereas upgrade kits like the MacSnap eventually became cheap & common.

cityzen,

You are thinking of the Hyperdrive. That pre-dated SCSI by quite some time.

dave, · Reply

There was the Paradise hard drive that tried to match the Design of the mac and was connected to the serial port. Needed a boot disk to activate and was a bit slower than the disk drive, but had 10 MB! (at least mine has - there was a 20MB version too)

ReiZu, · Reply

The RAM 'could' be replaced. I know, because I can remember upgrading my 128k machine to 512k on my kitchen table. I wouldn't recommend anyone try it because it's a lot of chips to unsolder.

john, · Reply

Back in those days I made a good bit of money upgrading and repairing these old Macs. The RAM upgrade was unsoldering the old RAM, replacing with 256K x 1 chips, and there was a little circuit board that soldered into the 7 solder flow through holes located at one end of the 68000 CPU (next to the resistor pack).

I still have a good bit of Mac 128K parts and pieces in storage.

Raymond Flowers,

Please please please shine a flashlight in the case. It has the signatures of the team that designed this mac engraved in the plastic.

pinky, · Reply

Seriously, iFixit? Complaining about the non-user upgradeable RAM? Who would ever need more than 128k of RAM??

JM Palacios, · Reply

But you could upgrade the memory. I did it on mine!! Going from memory:

1) order 16 DIP dynamic RAM memory chips (4164, with 64 kilobits each) for a few hundred bucks total.

2) Carefully bend up the /RAS pin (or maybe it was the /CAS pin) of each DIP

3) Piggyback the DIPS onto the existing memory chips, and solder the other 15 pins on each one.

4) Solder a wire daisy-chaining the bent /RAS pins on all 16 of the new 4164s.

5) I forget whether you had to dead-bug a 74xx TTL onto the board, or if the appropriate chip-select was already in the circuitry, but somehow you got the right signal to go to the daisy-chained RAS line.

And that's all there is to it.

David Palmer, · Reply

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