Somewhere in the mid to late 1990s I picked myself up a Macintosh Plus for the sum of $60AUD. At that time there were still computer Swap Meets where old and interesting equipment was around, so I headed over to one at some point (at the St Kilda Town Hall if memory serves) and picked myself up four 1MB SIMMs to boost the RAM of it from the standard 1MB to the insane amount of 4MB. Why? Umm… because I could? The RAM was pretty cheap, and somewhere in the house to this day, I sometimes stumble over the 256KB SIMMs as I just can’t bring myself to get rid of them.
This upgrade probably would have cost close to $2,000 at the system’s release. If the Macintosh system software were better at disk caching you could have easily held the whole 800k of the floppy disk in memory and still run useful software!
One of the annoying things that started with the Macintosh was odd screws and Apple gear being hard to get into. Compare to say, the Apple ][ which had handy clips to jump inside whenever. In fitting my massive FOUR MEGABYTES of RAM back in the day, I recall using a couple of allen keys sticky-taped together to be able to reach in and get the recessed Torx screws. These days, I can just order a torx bit off Amazon and have it arrive pretty quickly. Well, two torx bits, one of which is just too short for the job.
One thing had always struck me about it, it never really looked like the photos of the Macintosh Plus I saw in books. In what is an embarrassing number of years later, I learned that a lot can be gotten from the serial number printed on the underside of the front of the case.
Manufactured in: F => Fremont, California, USA Year of production: 1985 Week of production: 14 Production number: 3V3 => 4457 Model ID: M0001WP => Macintosh 512K (European Macintosh ED)
Your Macintosh 512K (European Macintosh ED) was the 4457th Mac manufactured during the 14th week of 1985 in Fremont, California, USA.
Pretty cool! So it is certainly a Plus as the logic board says that, but it’s actually an upgraded 512k! If you think it was madness to have a GUI with only 128k of RAM in the original Macintosh, you’d be right. I do not envy anybody who had one of those.
Some time a decent (but not too many, less than 10) years ago, I turn on the Mac Plus to see if it still worked. It did! But then… some magic smoke started to come out (which isn’t so good), but the computer kept working! There’s something utterly bizarre about looking at a computer with smoke coming out of it that continues to function perfectly fine.
Anyway, as the smoke was coming out, I decided that it would be an opportune time to turn it off, open doors and windows, and put it away until I was ready to deal with it.
One Global Pandemic Later, and now was the time.
I suspected it was going to be a capacitor somewhere that blew, and figured that I should replace it, and probably preemptively replace all the other electrolytic capacitors that could likely leak and cause problems.
First thing’s first though: dismantle it and clean everything. First, taking the case off. Apple is not new to the game of annoying screws to get into things. I ended up spending $12 on this set on Amazon, as the T10 bit can actually reach the screws holding the case on.
Cathode Ray Tubes are not to be messed with. We’re talking lethal voltages here. It had been many years since electricity went into this thing, so all was good. If this all doesn’t work first time when reassembling it, I’m not exactly looking forward to discharging a CRT and working on it.
You can see there’s grime everywhere. It’s not the worst in the world, but it’s not great (and kinda sticky). Obviously, this needs to be cleaned! The best way to do that is take a lot of photos, dismantle everything, and clean it a bit at a time.
There’s four main electronic components inside a Macintosh Plus:
The CRT itself
The floppy disk drive
The Logic Board (what Mac people call what PC people call the motherboard)
The Analog Board
There’s also some metal structure that keeps some things in place. There’s only a few connectors between things, which are pretty easy to remove. If you don’t know how to discharge a CRT and what the dangers of them are you should immediately go and find out through reading rather than finding out by dying. I would much prefer it if you dyed (because creative fun) rather than died.
Once the floppy connector and the power connector is unplugged, the logic board slides out pretty easily. You can see from the photo below that I have the 4MB of RAM installed and the resistor you need to snip is, well, snipped (but look really closely for that). Also, grime.
Cleaning things? Well, there’s two ways that I have used (and considering I haven’t yet written the post with “hurray, it all works”, currently take it with a grain of salt until I write that post). One: contact cleaner. Two: detergent.
I took the route of cleaning things first, and then doing recapping adventures. So it was some contact cleaner on the boards, and then some soaking with detergent. This actually all worked pretty well.
Note that C30, C32, C38, C39, and C37 were missing from the kit I received (probably due to differences in the US and International boards). I did have an X2 cap (for C37) but it was 0.1uF not 0.47uF. I also had two extra 1000uF 16V caps.
Macintosh Repair and Upgrade Secrets (up to the Mac SE no less!) holds an Appendix with the parts listing for both the US and International Analog boards, and this led me to conclude that they are in fact different boards rather than just a few wires that are different. I am not sure what the “For 120V operation, W12 must be in place” and “for 240V operation, W12 must be removed” writing is about on the International Analog board, but I’m not quite up to messing with that at the moment.
So, I ordered the parts (linked above) and waited (again) to be able to finish re-capping the board.
I found https://youtu.be/H9dxJ7uNXOA video to be a good one for learning a bunch about the insides of compact Macs, I recommend it and several others on his YouTube channel. One interesting thing I learned is that the X2 cap (C37 on the International one) is before the power switch, so could blow just by having the system plugged in and not turned on! Okay, so I’m kind of assuming that it also applies to the International board, and mine exploded while it was plugged in and switched on, so YMMV.
Additionally, there’s an interesting list of commonly failing parts. Unfortunately, this is also for the US logic board, so the tables in Macintosh Repair and Upgrade Secrets are useful. I’m hoping that I don’t have to replace anything more there, but we’ll see.
But, after the Nth round of parts being delivered….
Yep, that’s where the exploded cap was before. Cleanup up all pretty nicely actually. Annoyingly, I had to run it all through a step-up transformer as the board is all set for Australian 240V rather than US 120V. This isn’t going to be an everyday computer though, so it’s fine.
Woohoo! It works. While I haven’t found my supply of floppy disks that (at least used to) work, the floppy mechanism also seems to work okay.
Next up: waiting for my Floppy Emu to arrive as it’ll certainly let it boot. Also, it’s now time to rip the house apart to find a floppy disk that certainly should have made its way across the ocean with the move…. Oh, and also to clean up the mouse and keyboard.
Thanks to my most recent PR being merged, op-build v2.5 will have full support for the Raptor Blackbird! This includes support for the “IPL Monitor” that’s required to get fan control going.
Note that if you’re running Fedora 32 then you need some patches to buildroot to have it build, but if you’re building on something a little older, then upstream should build and work straight out of the box (err… git tree).
I also note that the work to get Secure Boot for an OS Kernel going is starting to make its way out for code reviews, so that’s something to look forward to (although without a TPM we’re going to need extra code).
I have done a few builds of firmware for the Raptor Blackbird since I got mine, each of them based on upstream op-build plus a few patches. The previous one was Yet another near-upstream Raptor Blackbird firmware build that I built a couple of months ago. This new build is based off the release candidate of op-build v2.5. Here’s what’s changed: