3D Printing CPU Trays

Better protection and storage for old Socket 7 and Socket 370 CPUs.

As you may know, I’ve been amassing a bit of a collection of retro hardware from the early to late nineties. This includes a number of CPUs from that era – especially those of the socket 7 variety. Storing these has been a bit of a challenge. I’ve never been satisfied with the protection a static bag alone provides for the delicate pins, and I don’t want to wrap up each CPU in bubble wrap either.

About ten years ago, I used to write PC hardware reviews and would quite often get processors from AMD in these neat little trays. Sometimes they held a single CPU, and sometimes as many as eight. They weren’t anything fancy but were perfectly sized for the chips and made of rigid plastic to protect the pins. You can still find these trays on eBay for more modern socket types, but they are much harder to come by for old processors.

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There are many varying socket 7 and socket 370 CPU designs out there.

Having acquired a 3D printer earlier this year, I thought this would be the perfect project to learn how to create 3D models from scratch. Up until now, I’ve mainly just printed community provided models and haven’t really done anything from scratch aside from some very basic shapes.

Getting the Measurements

I had already printed a couple of single CPU protectors from Thingiverse, but they were either not a good fit, used too much filament or took too long to print. I also wanted something that I could put a lid on and create trays that hold more than one CPU. These existing models gave me some ideas, but ultimately, I’d need to take some precise measurements of my CPUs and start from the ground up.

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A digital measurement caliper. A must-have for anyone with a 3D printer.

To begin, I used a ‘digital caliper’ tool that I purchased on Amazon for about $15. I can’t say enough how helpful this tool is to get precise measurements – it makes designing your objects so much easier.

To make sure the tray would work with a wide variety of socket 7 and socket 370 processors, I took a sample of each type I had in my collection:

  • Intel Pentium P54C (133MHz, ceramic top)
  • Intel Celeron Mendocino (400MHz, metal heatspreader). Same design and dimensions as later Pentium MMX CPUs.
  • Intel Pentium 3 (1000MHz Coppermine, no heatspreader)
  • Intel Pentium 3 (1400MHz, Tulatin, different heatspreader design)
  • Cyrix 6x86L (133MHz, gold-top, short heatspreader)
  • AMD K6-2 (500MHz, full heatspreader)
  • AMD K5 (100MHz, similar to Cyrix heatspreader).

Measuring all of these processors got me to the following conclusions:

  • The dimensions varied very slightly, but all were about 49.5mmx49.5mm +/- 0.1mm.
  • Pin height is 3mm on all CPUs
  • Most CPUs had a notch out of the corner, but some didn’t – like Coppermine P3s.
  • CPU thickness (not including pin height) varied from processor to processor due to the heatspreader designs. The thinnest was the P3 coppermine at only 2mm where the exposed core is located. The thickest was the Tulatin at 3.4mm.

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The 286 Revival

Being a retro PC enthusiast, my eyes are always open for deals on old hardware. A couple of weeks ago I came across an eBay listing for an as-is “Motherboard with ISA slots”. Looking closely at the posted images, I could see that the board was late-80s to early-90s vintage with sockets for individual memory ICs rather than the usual 30-pin SIMMs. Straining my eyes, I could faintly make out the markings on a Siemens brand 12MHz 286 processor. Having never owned a 286, I thought this may make a fun new project.

 

It was listed as-is because the seller didn’t have the hardware to test it. This is always a risky proposition, but when dealing with AT based systems, chances are that most people genuinely won’t have what’s needed. This is especially true if the seller doesn’t specialize in vintage hardware – which seemed to be the case here. At only $17.99 CDN, I thought it was worth the risk and I bought it.

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5.25″ Floppy Drive Alignment

About a year ago, I bought a dusty old Panasonic WU-475 1.2MB 5.25” floppy drive from someone on Kijiji. It was being sold as-is, but for the price I decided to give it a go. To my surprise, it seemed to work initially, but within a few minutes it began to emit a horrid clanging and grinding noise. After opening the drive up, it was clear that the stepper motor had completely ceased up.

After applying some lubricant to the rail and cleaning the drive out, the motor was again functional. Thinking it would be good to go, I installed it and tested it out again. Excitement quickly turned to disappointment, however, when I discovered that the drive could no longer read any of my 5.25” floppies. After troubleshooting for a while, I discovered that if I formatted a disk using the drive, it could be read/written just fine. It was only diskettes from other sources that wouldn’t work. This behavior seemed to indicate that the drive somehow went out of alignment during my disassembly and cleaning.

I didn’t know much about floppy alignment aside from the fact that some specialized equipment that I didn’t have would be needed to correct the problem. Generally an oscilloscope is used to take readings during sector reads and then fine adjustments are made until the waveform looks correct. This was the suggested method I discovered in the Panasonic service guide for the WU-475.

Discouraged, I had shelved the drive and let it sit for the better part of a year. Fast forward to May 5th – the 26th anniversary of the classic PC game Wolfenstein 3D. It was time to do something retro. I really wanted to get this drive working again, so I did some more research on the subject. That’s when I came across an old thread at the Vintage Computer Forum. A commenter named Rick discussed a great piece of software called ImageDisk by Dave Dunfield. Because I had some brand new 1.2MB IBM formatted diskettes that had never been used or formatted by another drive, I could use these as a reference point and make the necessary adjustments. At any rate, it was certainly worth a try!

 

Every drive is different, but the WU-475 has a pair of screws that hold the stepper motor in position. The screw openings are not perfect circles and allow the mechanism to be slid back and forth a millimeter or so in each direction.

 

Firing up ImageDisk and running the alignment test, I was initially greeted by lots of question marks scrolling down the screen indicating that each sector could not be read. As I loosened the screws and slid the mechanism forward slowly, the PC speaker sprung to life and began to beep indicating successful reads. Once I had it in the position that seemed to yield the best results, I scrolled through all 80 tracks to ensure they could all be read. I then tightened the screws well and lo and behold, the drive works wonderfully again! I’m sure my alignment isn’t perfect, but for all intents and purposes, the drive works.

It’s always a great feeling when you can restore something old and forgotten. As always, do this at your own risk. Making adjustments like this on a live system is inherently risky, so be careful!

Unboxing a 22 Year Old Microsoft Mouse

Finding a functional serial mouse for my ongoing 486 restoration project has been a challenge. Up until now, my retro rigs have had PS/2 ports that work with a variety of older optical mice. This isn’t the case with many custom-built systems from the early to mid-nineties. Unless your system was an IBM or some other name brand, you likely had to use a serial mouse.

Because of the peripheral divide in those days, there was demand for PS/2 as well as serial mice. This prompted manufacturers to create what was then known as ‘combo mice’. These mice would come with a simple PS/2 to serial adapter to allow support for both standards. When it came to keyboards, most if not all PS/2 keyboards were compatible with the common 5-pin DIN connector with a simple adapter. This is because the two connectors are electrically compatible and just need pin translation. With mice, however, this is not the case. For a PS/2 mouse to work with a PS/2 to serial adapter, it must have hardware support for both standards under the hood. Today I’m going to be looking at one of the iconic combo mice from the mid-nineties – the Microsoft Mouse.

msmouse_1

I was fortunate enough to find this ‘new old stock’ mouse on eBay from a Canadian seller. It was brand new and still sealed, which is quite rare these days. Most of the serial compatible mice I’ve come across are quite worse for wear and demand exorbitant prices.

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The 486 Restoration – Part 3

Welcome to part three of my 486 restoration project! Check out part one and two for more information on the parts I rescued from a badly neglected machine. I’m happy to report that the purchase of this banged up machine was not in vain. It didn’t come without it’s share of challenges but as you’ll see in this installment – it’s alive!

After removing the barrel battery and constructing an external battery pack in part 2, the next order of business was to get the machine put together on the work bench and powered up.

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My test-bench isn’t pretty but it’s functional!

I’m using a modern PFC Seasonic 350W power supply with an AT 12-pin adapter. These old systems run almost entirely on 5 volt power and draw nothing from the 3.3V and little from the +12V rails. This can cause problems with some newer PSUs, but this Seasonic model fairs well with a 130W rating on the 5V rail. The only side effect of this power draw imbalance is a higher than usual +12.6V on the 12V rail. It’s not ideal, but I’d rather this than a flaky 25 year old AT power supply.

Since the system didn’t come with a video card, I pulled out an old ATI Mach 32 ISA card from the parts bin.

 

I recently picked this up from the great folks in the computer recycling department of The Working Center in Kitchener. It was sitting in a box full of old PCI graphics cards destined for e-waste. It’s always awesome to keep classic parts out of the landfill and support a great cause at the same time.

Continue reading “The 486 Restoration – Part 3”

The 486 Restoration – Part 2

Welcome to part two of my 486 restoration project! In my last post, I took a look at some of the rescued parts from a badly neglected tower. Today, I’ll be going through my adventures of getting a functional CMOS battery working on this system.

As mentioned briefly in part one, most 386 and early 486 systems included what are referred to as ‘barrel batteries’. These are rechargeable nickel cadmium (NiCAD) batteries and are usually rated at 3.6V fully charged. Unlike the coin cell batteries in newer systems, the battery charges whenever the system is powered on. In theory, this was great because the CMOS battery could last a long time in the system. Using a multi-cell rechargeable battery increases the cost of the board, so the CR2032 coin cell solutions were most likely used for cost savings first and foremost in the years following. This is all well and good, but nobody really envisioned these systems to be in use 25 years later as is the case with this system here.

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A 25 year old Varta 3.6V NiCAD – it’s gotta go before the inevitable happens.

A quick google search on these barrel batteries, and you’ll see just how problematic these can be when they age. Not only can they leak and cease to function, but when they do they are very corrosive to copper traces and other types of metal on the board. If caught early enough, the board can be cleaned and may still be functional. Unfortunately, the damage can sometimes be permanent.

Continue reading “The 486 Restoration – Part 2”

The 486 Restoration – Part 1

As you may have noticed in my recent Building a Retro Gaming Rig series, I’m quite passionate about 1990s era PC hardware. Machines from this time are very nostalgic to me as this is when I really started getting interested in PCs and technology in general. Granted, PC gaming is what really drove my interest in hardware initially, but down the line, I really started enjoyed the hardware just for the sake of it.

I’ve only recently started acquiring and collecting vintage hardware in the last year or so, but I’ve always been drawn to 486 systems. Although we had an old monochrome 8-bit machine growing up – some kind of XT clone – the first PC I was really interested in was a 486 system bought in 1994.

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This won’t be the first 486 system I have in my collection. I got a well maintained DEC low profile system from my brother-in-law last summer. It’s a nice system that I hope to take a look at in another post, but it’s very integrated. Everything is on-board and proprietary so it leaves very little room for tweaking. That said, I really wanted something I could customize.

Today’s project all started with an ad on Kijiji I stumbled on a few weeks back – a 486 tower system in “working condition”. Inspecting the posted images carefully, I could see that the system was far from complete – it was missing a video card and didn’t have a hard drive.

Continue reading “The 486 Restoration – Part 1”

Building a Retro Gaming Rig – Part 6

It’s been a while since my last retro build post, but the build is finally complete! Actually, it’s been done for several weeks, but I just haven’t have time to break out the camera and get some pictures.

Without further ado, let’s have a look at the finishing touches and the final build!

Completed Build

For the case, I decided to use an old Antec NSK 3480 that I had lying around. I love the very simple appearance, but most of all, the small dimensions. With a depth of only 14 inches, it’s only as deep as it is tall. This can make for some challenges, but also makes it a perfect fit for slim boards.

Although it really doesn’t look like a retro box, I like that it’s very unassuming and feels a lot like a ‘sleeper’ build. I’ve got an old Pentium 90 and yellowed 486 rig that I’ll save for that true old-school appearance!

retro6-4

The Antec case was perfect for the MSI MS-6160 board. It even left enough space at the front of the case for the IDE-to-SD adapter board. For more detail on the motherboard, check out Part 3 of the series.

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Building a Retro Gaming Rig – Part 5

In Part 4 of this series, I took a look at some sound card options. I’m now getting a lot closer to having this build finished, but there is still one key piece missing – storage.

When dealing with old hardware, hard drives simply don’t age well. Anything with moving parts is prone to failure and degradation over time. Not only this, but as the bearings wear down, the drives begin to have an annoying whine and droning noise that can be heard rooms away.

I’m all for the genuine nostalgic experience, but slow and noisy drives with 20 years of wear behind them are not something I’m particularly interested in. That said, I knew that I wanted to retrofit a modern storage solution to work with this machine.

Challenges and Limitations

Having worked with older hardware before, I was prepared for some challenges along the way. There are numerous drive size limitations and other BIOS quirks that I’d need to navigate around. Below are just a few:

  • Most 486 and older systems are limited to a 504MB hard drive due to a limit of 1024 cylinders being supported in the BIOS.
  • Many systems in the late nineties simply didn’t support drives larger than 32GB due to other BIOS limitations.
  • With a newer BIOS, some IDE systems can support drives as large as 128GB, which was the LBA limit with an ATA interface.

Clearly there are newer IDE drives with capacities beyond 128GB, but these drives require newer Ultra ATA 100/133 controllers. After doing some testing, I discovered that the Asus P2B that I outlined in Part 1 of this series had a 32GB drive limitation with the latest production BIOS and a 128GB limitation with the newest beta BIOS. The MSI MS-6160 that I covered in Part 3 was limited to 32GB. Since this was the board I wanted to use, I could only consider IDE solutions of 32GB or less if I wanted to stick with the onboard controller.

Continue reading “Building a Retro Gaming Rig – Part 5”

Building a Retro Gaming Rig – Part 4

Welcome to part 4 of my Building a Retro Gaming Rig series. Today I’ll be looking at some sound cards for the build.

Back in the early nineties when I first started taking an interest in PC gaming, most entry-level systems didn’t come with a proper sound card. I still remember playing the original Wolfenstein 3D using the integrated PC speaker on my friend’s 386 system. All of the beeps, boops and tones that speaker could produce still feel somewhat nostalgic to me. We had a lot of fun with games of that era so didn’t really think much about it. It wasn’t until 1994 that I got my first 486 system and a proper Sound Blaster 16. It was then that I really realized what I was missing out on. Despite having really crappy non-amplified speakers, the FM synthesized MIDI music and sound effects were just so awesome. And who can forget messing around with ‘Sound Recorder’ or playing CD audio in Windows 3.11!

With all that in mind, it was clear that I needed a proper sound card for my retro build. But that really isn’t just a ‘checkbox’ to tick – on machines of this era there really was quite a difference between cards and to get the proper vintage experience I’d have to choose correctly.

Continue reading “Building a Retro Gaming Rig – Part 4”