As a child of the late 70's and elementary school student of the 80's, I have always been fascinated by these little beige and platinum boxes and their tiny B&W screens. A few popped up beside the Commodore Pets and Apple ][e's in our school library. Of course, we were never actually allowed to touch one of these icons of design and function. Stray too close and the librarian would appear out of nowhere to protect the secrets of the box of mystery.
For years I've wanted to convert one of these 'all in one' 1980's Mac's into a useful, modern computer. With the memory of that librarian reduced to only a few nightmarish flashbacks a month and my own money to waste how I see fit (with the blessing of my very patient and understanding wife), I give you a step by step account of the merger of a 1987 Mac Plus and Raspberry Pi2 model B, creating...
Teachers! Did you use this instructable in your classroom?
Add a Teacher Note to share how you incorporated it into your lesson.
Step 1: ApplePi: So You Want to Build a Modern Vintage Computer?
The first step was to find a suitable 68K compact Mac to serve as host for the modern components.
A quick search of Kijiji and eBay will reveal hundreds of available machines, most of which are priced around the same as when they were new in the 1980's...
I have seen these machines at garage sales from time to time, so it took a bit of digging but I finally found a person selling a non-working Classic II (circa 1991) in Ottawa for $10 (about a 3 hour drive each way).
1991 is a little 'modern' for my taste, but beggars can't be choosers.
We made made a trip of it, visiting friends in the area. I met with the seller who actually had a basement full of vintage computers, from TRS80's to Amiga's and even a few Unisys Icons.
I noticed a Mac Plus in the corner which he agreed to sell me for $40. Perfect!
Being an quasi-antique, not to mention a piece of art, I really wanted to avoid altering the case in anyway that involved physically cutting or destroying parts of it, inside or out.
Now, pretty much all electronics from the 1990's, 80's and even 1970's, the once pristine plastic cases have turned a hideous smokers cough yellow due to UV light reacting with the fire retardant chemical Bromine.
This can b fixed by making and applying a simple concoction you can search for on the internet called Retr0bright.
Extra... Bonus points for naming the game the Step 1 title is referencing (no searching). :)
Step 2: Retr0bright the Simpsons Out of Your Vintage Case
After locating the vintage computer, the first thing you'll notice is that it looks more like a refuge from the Simpsons then the original colour in your memory.
This is common in all vintage case plastic. It is caused by UV light reacting with the chemical Bromine which was added to plastic as a fire retardant.
To restore the case to it's near original colour, I experimented with several percentages of the ingredients and found the following recipe worked well.
I applied the Retr0bright to the Classic II case first, as it was the more expendable test subject then the Mac Plus case I really wanted.
You can see the before/after comparison in the side-by-side image of the two case bezels. The now platinum Classic II bezel on the right was originally the same yellowish colour as the Plus bezel on the left.
- Oxi Clean (powder, not liquid)
- 3% Hydrogen peroxide
- Xanthan gum
- Container to mix it all up in
Make the goop like this:
Safety glasses and gloves on.
Pour 473ML Hydrogen peroxide into a container you plan to make this in.
Slowly add 1TBSP of Xanthan gum.
~Mix until there are no clumps.
Add 2 TSP of Glycerine.
~Blend it all up.
Add 1/4 TSP of Oxi Clean
Start applying in the sun or under a UV light.
Search the web for more recopies and ideas. The one here worked well for me, you may find others that work even better.
I popped off the multi-coloured apple badge from the front bezel. It is made of metal and held in place with a little glue. It's easily removed by pressing a paperclip through the hole in the rear of the bezel, directly behind the apple badge.
I opted to wait for a nice sunny day and use the sun as my UV light source instead of buying a specialty UV light bulb. You don't actually have to have a fully cloudless sky, UV penetrates the cloud layer no problem. It's just nicer to work outside when it's nice out.
I applied the concoction to the case plastic using a narrow paintbrush, rotating the case and bezel regularly for even sun exposure.
The whole fun in the sun process took approx. 4 hours to complete. Time will vary based on the amount of discolouration to correct, UV amount, H2O2 %, etc...
VERY IMPORTANT - Keep applying the Retr0bight until the case has reached the desired de-yellowfication.
If you let it dry on the case it will discolour the plastic pertinently.
Once the plastic has reached a point you are happy with it, rinse it off well with water, getting into all the little nooks and crannies (see drying warning above).
Both the Classic II and the Plus bezels have a silk screened model name. With my 3% concentration of H2O2 I had no issues with the screening coming off. I have read you need to be careful with higher concentrations.
Just a note, This is not a permanent solution to de-yellowing plastic. It works very well, but Bromine still exists in the case plastic. In time, with exposure to UV light it will react as it did over the past few decades and re-yellow the plastic. So another Retr0bright treatment may be required 5, 10, 15 or 20 years from now.
Step 3: I Can See Clearly Now... 9" B&W Screen Swapout
The original screen for nearly all compact Mac's (the Colour Classic line was an exception) was a 9" B&W CRT with a 4:3 aspect ratio.
I searched for quite awhile for a 9" colour flat screen with a 4:3 aspect ratio that would be an easy swap out... but does such a beast exist? Maybe... I never found one.
Today's world is all about HD 16:9 screens. It was actually something of a minor miracle I came across an 8" 4:3, complete with driver board that accepted HDMI input.
The cost was around $50 Canadian for the screen with driver on eBay.
Just a heads up, the original CRT is connected to a flyback transformer and an array of capacitors which can hold a charge long after power has been removed from the computer. Before you start pulling wires off the CRT to remove it, discharge the unit safely first!
The original 9" CRT was secured to the front bezel by 4 screws, one in each corner (you can see the holes in the picture).
Due to the new flat screen being only 8" and also a flat screen with nowhere to actually screw through (bad idea), I opted to built a bracket of my own to fill the gap around the screen edge and bezel. It also provided a place to drill 4 mounting holes that match the location of the originals.
I love the appearance of aluminum checker plate, it's easy to work with cuttingwise and small sheets are readily available at most hardware or automotive stores (big plus in the smaller city I live in).
I used the physical flat screen dimensions to mark out the cut lines on the aluminum, marking them slightly smaller then the actual screen (we're talking a millimeter or 2 smaller), then drilled a pilot hole and used my jigsaw to zip out the center rectangle.
I measured the distance between the bezel's existing CRT screw holes then transferred that measurement to the aluminum and drilled the appropriate hole in each corner.
I filed the edges of the cut aluminum smooth from burrs and then painted the entire metal surface with a black rubberized spray paint.
This was personal preference, the bare metal or any other colour would finish it nicely too.
Be aware, if you are using 'normal' spray paint on aluminum, make sure to etch the aluminum first for proper adhesion.
The physical flat screen was attached to the metal bracket at first using good ol' duct tape, then, once temporarily placed in the bezel and verified as perfectly centered, I used PL adhesive (sparingly!) to secure it from the back.
Once dried, I applied painters tape to the screen and the surrounding metal bracket, leaving just the edged where the screen meets the exposed metal. This was just a few millimeters of space all the way around.
I ran a bead of black caulking around the exposed perimeter of the screen in the gap between the painters tape.
This hid the joint between the screen and the metal bracket a bit nicer then just the metal edge alone.
I opted to use the painters tape to assist in keeping the edge of the caulk straight and clean. Caulking is an art, and I'm still at the crayon level of caulking art class...
Remove the painters tape fairly soon after applying the caulk bead so it doesn't cure over the tape. Messy and peely...
Depending on the paint you use on the metal you may need to wait a set amount of time for it to be safe to apply painters tape to the painted metal, else the paint lift off with the tape!
That's pretty much the process of installing the screen. The only negative I ran into was that the original CRT had a curve it its surface. This curve was molded in the plastic bezel for a nice seamless fit.
The flat screen is just that... flat... so although not horrible looking, technically there is a small gap of varying distance around my new screen where the old CRT use to curve and meet the plastic bezel.
One day when I get time (haha, I can hear my wife laughing) I would like to try using the original CRT and molding a piece of transparent acrylic to match it's curvature, then attach it in front of the flat screen, giving it the original CRT bubble look. Maybe even airbrush the edges black to hide the gap more. But for now... the screen is in. :)
Step 4: May the ReinFORCEd Back Ports Be With You!
The Mac Plus had an array of ports located at the rear. I thought it would be fun to try and keep the look of the original ports but replace them with functioning modern equivalents.
The original ports were actually part of the logic board assembly (that means motherboard for the non-apple world) which sat horizontally at the bottom of the case. It was held in a metal frame along with the floppy drive, etc...
Under the logic board and then turning 90 degrees, extending up the back to just above the port holes (no, not the kind on a ship... har har) was a 'paper-ish' shield. The bottom part that ran under the logic board was this paper like material, the rear port section was actually a thin metal sheet glued to the paper material.
Using this shield as a template made it very easy to build my own metal port support so I would have something rigid to attach the new modern ports to, as plugging in USB devices and yanking them out is fairly stressful and fatiguing on materials.
I wanted to keep the DB9 connector look of the originals, so I purchased a bag of DB9 ports, used my drill press to "hollow them out" (basically drill out the plastic bit in the middle that's holding the pins, leaving only the outer metal shell).
I purchased a dozen male/female USB extension cables that had perfectly sized female ends and used PL adhesive to secure the female ends into the now hollowed out DB9 shells (see images).
Doing this also allowed me to secure the USB/DB9 shells to the metal bracket I made using the original hex nuts.
I added a keystone style wall jack RJ45 connector to one of the port locations for wired Ethernet, a small female stereo audio jack to the original audio out port location, a DB9 male connector with a TTL serial converter and the Pièce De Résistance... an original 1990's Griffin iMate ADB to USB converter so you can connect any vintage ADB keyboard, mouse or possibly other device from years gone past directly to the Raspberry Pi. :)
The brace is made from a piece of scrap aluminum, I used the original shielding paper/metal to trace out the exact dimensions of the existing port openings, and held the db9 USB connectors in place to marked out where the holes for each of the hex nuts would need to be drilled.
I used a jigsaw to cut the basic outline of the plate from the scrap of aluminum, then I used my rotary tool to cut and grind out the actual keyed DB9 port holes.
The original SCSI connector port hole was wide enough to squeeze two USB/DB9's into side by side. I just had to slightly trim the inside edges of the two DB9's to fit (see images).
The keystone jack for the Ethernet port I attached with PL and the audio jack used it's actual screw on nut to sandwich the port to the brace.
The serial port TTL board attached the same as the modified USB/DB9 connectors, with the included hex nuts.
The ADB converter was removed from it's plastic housing and placed inline with the printer port hole, slightly recessed inside the plastic for protection.
Each of the USB port and ADB cables run back to a 7 port powered USB hub, which then runs into the Raspberry Pi.
The Ethernet jack has a short jumper cat5e cable punched down to it that runs to the RJ45 Ethernet port of the Pi.
I matched the location of the original screw holes on each side at the rear of the case, and used nuts to secure the new back brace plate using the original torx screws.
So far, no vintage cases has been maimed or cut in the making of this project. :)
Step 5: Securing the Bits N' Bytes
So with the screen installed and the back brace plate securely holding an array of cool looking db9 USB ports (among other things) it's time to install the actual Raspberry Pi and support components into the little Plus case.
The first issue was, where to mount the modern hardware?
I had to install the driver board for the screen, the Pi itself, and a 7 port USB hub, plus power distribution for all of them.
I was determined to mount the components without modify the original case by drilling or running screws through it. But there isn't really a good way to do this, it's pretty much bare, flat plastic walls inside.
Luckily, I had the original components laying on the table beside me. The power/sweep board, which originally mounted vertically against the right wall (patient right) of the Plus case was the perfect size and dimensions to fit in the space, complete with the little 45 degree angle edge following the cooling vent design on the top of the box.
Why not build a wooden mounting board matching these dimensions and use the existing molded plastic in the case to hold it in place?
Wait... why not use the actual original power/sweep board itself?
Impressive... most impressive...
The power/sweep board was pretty much either going into a storage box and into the basement, or more likely, into the trash.
So I set about desoldering all of the components from the power/sweep board, except for the original speaker, and the rheostat that served as the brightness knob located just under the screen at the front of the Plus.
I planned to connect the Pi's audio out through the rheostat to the audio jack so it can act as a crude volume control, or maybe even utilize that internal speaker somehow for that vintage sound quality.
As an added bonus, the outline of all components and their ID's were silk screened onto the power/sweep board, so it actually looked pretty nice with all the components removed. Like a perverse LEAN obsessed Engineer's dream (don't ask). :)
I have a collection of motherboard standoffs (brass hex nuts of varying lengths with a threaded male and female end) that I used to mount each of the modern components to various spots on the power/sweep board. I marked out the mounting holes with the actual components on the board, then used my drill press to zip the holes for the standoffs.
Make sure you mount the components within reach of each other for the cables/jumpers you have. Also, make sure you have enough clearance around things like ports/connectors to plug in everything that needs to be plugged in. :)
I mounted the Raspberry Pi just inset from the original PRAM battery door at the rear of the case, so I can access it's USB and Ethernet ports without having to open up the case should he need arise.
I did mount the Pi a little too high, since the top of the case is molded down to form a handle. So I had to use a couple of 90degree HDMI elbows to get the video cable up over and down to the video driver board. :)
Because the original internal metal chassis has been removed, I had to build two little "L" brackets, one for the top rear of the board, and one for the bottom rear, again utilizing the original torx screws with a nut to secure it in place. The bottom screw is shared with the rear port mounting plate I built earlier.
Another bonus of reusing the power/sweep board was that I could use the original AC power connector and on/off switch which were perfectly aligned to fit in the original power/switch openings at the rear of the case.
Because I had three separate components with 3 separate voltage & current draw requirements to power, I opted to cheat and just bought a small 4 port power block (powerbar) which I secured to the bottom of the case with PL.
I cut the 3 prong plug off (and most of the 4 foot cord) and soldered the power block into series with the original power receptacle and switch.
Just a heads up... by doing this you are playing with power off the mains (in my case, 120v AC up to 15A).
Don't do this unless you are confident in your experience and knowledge of electricity and tracing out the circuit paths.
By using the original receptacle and switch, I also used the original copper runs on the backside of the power/sweep board. I had to make sure none of these runs went anywhere I wasn't aware of, else I could have electrified portions of the power/sweep board (and more) that could pose a serious electrical shock or fire hazard.
If you are not comfortable using AC on the switch, you could wire up an alternative external supply, or even a battery powered option or you could still use the original switch with a relay or DC supply.
Note: in one of my photos, the grounding wire is not connected to the receptacle yet, I assure you it is in the final machine. :)
Step 6: USB, SD and RS-232... Oh My!
So back in step 4 I talked about the ports on the rear of the Plus case, the homemade db9 USB ports, Ethernet, rs232, audio and ADB.
On the front of the Plus, there is the standard 3.5" floppy disk slot (I can still hear the wine of the auto-eject) that was begging to be filled with something.
There's also the original telephone jack (RJ11) style connector that the keyboard used to connect to the machine in the lower front corner. Now a lonely empty hole.
First the floppy slot...
I searched and found a multi-card USB reader that had a nice long & slim profile. I didn't care about all the never-used cards it had sockets to accept, all I wanted was the SD and micro SD slots which were conveniently mounted directly on top of each other. I cut a small strip of aluminum to cover the narrow portion of the 3.5" floppy slot, filed the edges and painted it black with the same rubberized paint I used for the screen mount and used PL to secure it in place.
I then removed the plastic casing from the card reader and used PL to secure it to the rear of the bezel, keeping the SD/micro SD slots centered in the larger portion of the floppy opening.
For the original front keyboard port hole, I purchased a 90 degree USB elbow (male/female), and using my favorite tube of PL, secured it in place. I used a small clamp on both to hold them in place while the PL cured.
Both the card reader and front USB port are connected to the USB hub with short extension cables.
Step 7: Up and at Them!
It was a fun project I'd wanted to do for years.
I'm surprised how often I've actually used the little Plus for semi-serious work since it's completion.
Please contact me if you have any questions or comments!
Thanks for reading.