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A connundrum: Super clean original Macintosh II... keep it stock or swap in MEGA IIfx upgrade

Hello Everyone,

I've been lurking a bit. Your perspectives are greatly respected and appreciated.

So: I've been a vintage collector (read, borderline hoarder with a vague curatorial philosophy) for years. I've been lucky enough to come across lots of great finds and not have to put too big a financial investment in to my collection. Now I'm trying to take stock and really decide where the value and enjoyment in my collection comes from... clean up and curate what's valuable, and either sell, give away or ethically recycle the rest. (Tale as old as time around here I'd expect)

Many years ago I was gifted a Macintosh IIfx. I was fairly ignorant at the time, but it was from a client I was working for and I was assured it had been A BEAST back in the day. I didn't have space for the whole thing so I pulled the board, cards and HDD, and discarded the rest (it pains me to admit that now). It's been sitting on my museum wall for about 15 years. After doing some contemporary research I've discovered that it's an AVID MEDIA COMPOSER I box. It's got all the amazing cards. A full suite. RasterOps PaintBoard Prism GT video, DigiDesign ProTools card, ATTO Silicon Express IV Fast SCSI, NuvoTech NuvoLink II Ethernet, and the AVID Base+Composer and Janus MJPEG boards... all connecting cables... and the whole thing collecting a little dust and UV but in a carefully climate and humidity controlled setting. There is a tiny bit of capacitor induced corrosion but the open air display has minimized it and I can find no PCB lead degradation. I'm fairly adept at SMD rework and I've already ordered a cap replacement kit. I'm going to get it properly tended to no matter what. Incidentally if anyone on these forums has more knowledge or experience of the AVID MC I system I'd LOVE some more insights in to it. I do have a chain of 9.1GB SCSI drives I could attempt to get going... but I'm curious if my RaSCSI can emulate such madness 😇

Aaaaaaanyway, I know I could bench it and mock up a modern PSU, but that baby deserves some respect, so I was looking for IIfx chassis on Craigslist and eBay. Accessible history suggests that the IIfx is the white wale it is often reported to be, and I've only found ones that are either precious in their own right or KNACKERED. So I put my sights on a standard Mac II. I figured I'd find something with nice plastics but awful battery leakage and swap things in, mount the destroyed board on my museum wall as an homage and get that beast up. Lo and behold I found a full Macintosh II IN ORIGINAL BOX with foams and its original mouse and power cord... apparently excellent condition, with some paperwork and provenance for $300 delivered. I jumped on it.

I opened my "new" Macintosh II with joy, and it was in fact as advertised. EXCELLENT condition, and entirely stock... No PMMU, no IIx ROM, no upgraded SWIM.... original video card, 40MB SCSI and 800k floppy. Soldered VARTA batteries "Made in West Germany"🧐. No leakage. Visible but apparently minor electrolyte corrosion.


I've got both a clean FANCY IIfx board set and a clean STOCK Mac II. It's an embarrassment of riches.

What would you good folks do?


I will obviously clean, polish, recap and re-battery both systems in the least invasive way possible. My instinct is to swap in the IIfx board, get it a modern 128MB RAM kit, a SuperDrive, and put 7.6.1 on it, and just make the killer 68k mac of all time... with AVID and ProTools if I can find them... and relegate the Macintosh II stock board to a nice, grounded, climate controlled place on my museum wall, but then my IIfx will have a II faceplate, and it provenance will be nearly wiped clean.



Well-known member
Me being me: leave the II stock. If it survived that long, it would be nice being left as it was.


Is the Macintosh II the first rev (A?) with discrete NuBus controller and multiplexing ICs or the later NuChip rev?

If the former, leave is as is (unless you want to send the board my way of course!) If it's the NuChip revision, only LaPorta cares! ;)


Well-known member
mmm... what tasty caps you've got there...
I can smell the fish from here!
Great finds! I'd try to look for a donor case for your IIfx setup, but it's up to you in the end :)


Well-known member
If you want a complete collection, keep the II stock. If you only care about having a working IIfx, use the II case for that instead and enjoy it.


Well-known member
It sounds like such a nice Macintosh II, I'd keep it stock - provided it works well. If it was an old dodgy one not working, I'd throw that IIfx board in without question. A good proportion of Macintosh II were upgraded to IIfx machines so you're not committing any sins.


Well-known member
Because logic boards keep dying, there are significantly more cases out there than there are LBs. So if this were mine, I'd be inclined to keep the II stock, and look for another donor case for the IIfx. Might actually be worth posting in the Trading Post here to see if anyone has one (I only have one big box II, so that won't be me, I'm afraid!)

borderline hoarder with a vague curatorial philosophy

Well put. :-D


A - IIfx swap is totally reversible, no? So so fix both boards and use whichever you fancy until you can get a clean IIfx case.
B - Laser cut clear plexi display case for the IIfx board and NuBus Cards or the II?
C - mix of options A & B


Quarter inch laser cut Plexi and captive nuts. ;)


Well-known member
Since it's a revision B, I'd be tempted to pull the board, remove the old caps, recap it, pull the batteries, then stuff it into an antistatic bag. Save it for a nice II case, or, if you wind up finding another IIfx case somewhere, swap it back in when that arrives. Use the current II case for the IIfx guts for now. It'll just be a stealth FX, like the Apple IIgs upgrade kit machines, except that it'll look like an fx, minus the "fx".


Well-known member
I know for the IIfx, its at the top left of the board, right after the number (model number maybe?). Either A, B, or there's some really early ones I think with numbers?


Well-known member
A little OT: how does one tell II board revisions?

The main visual difference is that Rev A has more through hole components. Rev B has some early SMD components including leaky electrolytic caps.

Mac II Rev A:


Mac II Rev B:


Pics courtesey of https://recapamac.com.au/ (hope he doesn't mind me posting them here, you just never know when stuff is going to dissapear off the web!)
These are all great thoughts. My laser cutter is only 500x300mm, so I might have to make some phone calls. Does anyone have any drawings for Macintosh II dimensions or will this be from scratch... 🤔

I've attached a board shot of the "new" Macintosh II along with pictures from the eBay listing. It arrived unscathed and they boxed the box...

I'll try to scan the AVID card set soon


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Well-known member
Yeah, that's a Rev B board but since it's most likely fixable and you've got the original Mac II packaging I'd say leave it as is. Find another case for your IIfx project. Sorry, going back on what I said earlier. :)
As per @Unknown_K 's request here's the IIfx card set... There's something fishy. One of these cards doesn't fit in the Macintosh II... Now I'm wondering. I have a PowerMac 8100/80 that I'm pretty sure I got from the same client. It might be that they upgraded in to that when they got the "Janus Board" MJPEG card. I know the rest were originally in the IIfx. Does anyone have any experience with old Avid's? I'm finding scant info, as they seem to have been largely sold as complete suites with individual hardware not really marketed.

I've scanned them and reversed the backs so the circuits line up. Depth of field isn't great so detail is blah. I didn't have good lighting set up to do beauty shots 😉, but they should be okay for documentation. There's a backhaul connector between the two Avid boards. I don't have the breakout for the Pro Tools card... 😢


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