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

skeptechsguide

New Tinkerer
Jun 13, 2022
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Hello Everyone,

I've been lurking a bit, and I've fervently absorbed hours of @Branchus YouTube content. 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.

<EXECUTIVE SUMMARY>

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?


</EXECUTIVE SUMMARY>

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.

HAAALLLLLP!
 
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Kai Robinson

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Just my tuppence here, honestly, in this case, the II is worth restoring on it's own. IIfx cases are more abundant than working IIfx's, due to the double maxell bombs they frequently contain - I have two IIfx cases, one of which is being given away to @mg.man simply because it's huge, bulky and I only have the need/want for a single IIfx!

Find a case for the IIfx, even if it's just a II or IIx one, and rebuild the IIfx into it, instead - the II is often overlooked, and if it was knackered, I might say sure, dump the innards and use the IIfx in there, but if you genuinely have an original one with the original drive, IWM chip, AMMU chip etc - it's worth preserving and financially, if you were to resell, worth more in that state, too.
 

skeptechsguide

New Tinkerer
Jun 13, 2022
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I'm honestly surprised. I've been getting a lot of feedback along a similar vein. I'll try to document the fixes. Cap replacement kit is en-route.

So this is me formally putting out a call for a IIfx case in good nick. Happy to fairly compensate. I'm in NYC so if anyone has a lead....

Here's a bit of documentation from the eBay auction and some photos I've taken.

✔ Original FDD and HDD (800k/40MB) Drive
✔ IWM, HMMU, ROM,
✔ Tobi graphics with 8bit RAM
✔ Accessories, foams and box
 

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skeptechsguide

New Tinkerer
Jun 13, 2022
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Hello All,

So, I figured I'd post an update.

I ordered and received my capacitor repair kits and pulled the board and gave it a good look-over. I dusted it, cleaned it with iso and pulled all the bad SMD electrolytics via the twisting method. It was very quick and smooth and incurred no damage.

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I strongly endorse this method. I desoldered the large electrolytics.

I painted DeoxIT on to the corroded areas, SIMM slots and connectors. I let it sit overnight. I cleaned the DeoxIT treated areas with green scrubbing sponge (It's the perfect hardness to clean oxidation while minimizing damage to the solder mask, but it will cause minor degradation to raised areas and painted or silkscreen markings on chips, so be careful 😉). I searched the board and found only two traces that were visibly severed, connecting to the power button area.

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I repaired these traces with tinned wire strands. Additional to these I found several pads for the removed SMD electrolytic caps were corroded beyond usefulness and I had to use additional wire strands to build up areas to connect the new tantalum caps. Once those were in place I decided I should probably reflow solder paste for the new caps so that I wouldn't mechanically disturb the fragile ad-hoc pads. I gently applied the solder paste and used tweezers to place the new caps. I flowed the paste and was very happy with the behavior of the pads and the new SMD caps. It was surprisingly smooth.

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Then I added the large axial electrolytics. I created a wire harness for the new battery harness to attach to the back of the board. I used thin solid CAT5e wire terminated at the far end with JST-SM 4 pin locking connectors. I built a small holder from some perf board and two 1/2AA holders.

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This means the batteries can be held apart from the logic board and adhered with hook and loop straps in an archival way.

Finally it was the moment of truth. I have no idea how long it had been since the system had been powered on, but at some point you've got to try. I'd done a lot of work so I was skeptical that it would work... BUT IT DID!!! No chime, and I'd only installed one bank of RAM, but it WORKED! The hard drive spun up and booted in to System 7.0! Amazing!

I figured I was on borrowed time with the OEM Quantum 40MB HDD so I connected my RaSCSI and cloned the drive over to a new image. I'm glad I did, because the drive only lasted a few hours.... 💔 Luckily I'd gotten everything, so the software install can remain contemporary. The system must have come with 1MB of RAM, because it had 4x 256KB SIMMs and 4x 1MB SIMMs. I added the 256KB modules back so now I have a pretty humorous 5MB of RAM. I've ordered some Garrett's Workshop GW4194A 4MB modules that are supposed to behave on the Mac II. I'll see how they behave with the HMMU. My understanding is that it'll only see 8MB without the PMMU upgrade.

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So now my system is up and running with it's original graphics card, RAM and software configuration running off an external RaSCSI. The 800K floppy is very sticky so I still have to deal with that. Not sure if there's anything I can do to refurb the HDD. That certainly seems unlikely.

Refurbishment includes:

  • SMD recap to tantalums
  • Axial electrolytics replaced
  • Electrolyte corrosion cleaned
  • Corroded traces replaced
  • Servicable parts contacts cleaned and treated (SIMMs, NuBus, MOLEX, SCSI, Serial, ADB, Audio, Speaker, PSU)
  • Battery harness relocated and modified
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