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I am finally a Macintosh II owner again

markkrueg

Member
All my first jobs went toward saving up enough to buy a Macintosh II in my Junior year of high school in 1987. It was my prize possession and jump started my tech career. But I had to sell it around 1990. Today I received a working Macintosh II that is in much better condition than I expected. It boots off its original hard drive!

I've just begun cleaning and assessing on my ESD safe bench. I only booted once off the drive and then unplugged it. I plan to only spin it up one more time to do a full backup if I'm lucky. I'll install a newer SCSI drive from my stash or maybe some sort of modern replacement.

The board looks perfect. I can see no damage. I'll have to look over all the caps with magnification. I know many people say the batteries should be immediately cut out; so I'll probably have to do that soon as well. They look so perfect it will be hard to do it.

My next step is to find the keyboard I plan to use with it. I have my Apple Adjustable Keyboard in a box somewhere along with an ADB mouse. Time to search the house. Can't do much more with this machine until I find those.

Any advice is appreciated on proper maintenance necessary to keep this machine running for many years to come.

Mac_II.jpgdrive.jpgbooting.jpgmotherboard.jpg
 

ObeyDaleks

Well-known member
Congrats!! I too am especially fond of the OG Macintosh II and have a similar history with it. Looks like you have the Rev A board which is the better of the two since it has no surface mount caps. I never replaced any caps and most people agree that it's not needed. The batteries are actually pretty easy to replace with battery holders. I included a picture of mine for reference.

Otherwise, I would say give it a good dusting and you're good to go. Your board looks very clean. If you feel like pimping it out, these can run a Powercache or Turbo 040 (with an adapter), and of course any of the nubus graphics accelerators. Without the PMMU or the superdrive upgrade, you'll be a bit limited on RAM, but OS 7.1 runs great on it stock. The only thing I still plan to do is recap the PSU and find a quieter fan for it. But a part of me thinks the noise is part of the charm.

IMG_2907.jpg
 

markkrueg

Member
Thank you so much @ObeyDaleks! Your machine looks wonderful.

I do think mine is a Rev A, which is likely what my first Macintosh II was as well since I purchased it right when it came out. I'm thrilled to learn this, and also that I can avoid re-cap. I think I will do the same battery mod you did, as it looks really nice. I may cheat and try to cut the leads close to the battery and solder the new holders to those leads to avoid having to actually solder on the board. Or something. I'm not very confident in my soldering skills, but hope to improve by practicing on less precious equipment.

motherboard_rev.jpg

Do you know how to tell if it had a PMMU upgrade? Which socket would it be in?

chips.jpg

I believe I currently have 2MB RAM (8 NEC boards). Which is probably fine for my needs; but who knows.

It's all a lot nicer than my original machine; as I actually have a color monitor now. I was pleasantly surprised (and relieved) when my Dell 2001fp display worked just fine with one of my VGA dongles connected to the Toby card. Toby appears to have the RAM upgrade as all sockets are populated. Happy I kept those dipswitch video dongles around all these years.

I could never afford the color screen for my original Macintosh II so always only had the grayscale. I'm looking forward to some color Crystal Quest :)
 

Phipli

Well-known member
Not much to add. As above, no preemptive recap required.
I know many people say the batteries should be immediately cut out; so I'll probably have to do that soon as well. They look so perfect it will be hard to do it.
Batteries need replacing. Note it won't boot normally with no batteries, so get some new ones before you cut the old ones out. They should be OK for a few more weeks (do not leave it longer, they can go fairly suddenly and cause horrible damage) - since it's booting at least one still has some charge.
I believe I currently have 2MB RAM (8 NEC boards). Which is probably fine for my needs; but who knows.
You should be able to lift it to 8MB total pretty easily. Bigger SIMMs need to be super rare "PAL" SIMMs, but 1MB SIMMs don't have that limitation. 8MB works regardless of ROMs and MMU setup, and is fine for System 6 and even some stuff up to about System 7.1 or so.
 

ObeyDaleks

Well-known member
You can compare the board revisions here: Rev A, Rev B.

The MMU is the big black chip right above the CPU. The PMMU would be gold and would be labeled MC68851. Yours looks to be the original configuration which came with 2MB, upgradable to 8MB. The 68851 was later offered as an upgrade to allow for more RAM. The PMMU was exclusive to the Macintosh II due to its unique use of the 68020 processor. Later processors had paged memory handling built in. Just a bit of history. 8MB should be plenty for most software from that era. I would definitely upgrade to 8mb.

The Toby card is fine too, you don't need to upgrade unless you have a very specific use case.

Soldering the battery holders to existing leads may actually be more difficult than soldering the through-hole. Like you said, maybe you can practice some through-hole soldering first to get comfy with it. For most of these types of boards, you do need a decent iron that can supply enough power to heat up the ground plane. There are other options - for example, I believe I've seen some pictures of people using a battery pack attached with wires.

Good luck!
 

markkrueg

Member
Not much to add. As above, no preemptive recap required.

Batteries need replacing. Note it won't boot normally with no batteries, so get some new ones before you cut the old ones out. They should be OK for a few more weeks (do not leave it longer, they can go fairly suddenly and cause horrible damage) - since it's booting at least one still has some charge.

You should be able to lift it to 8MB total pretty easily. Bigger SIMMs need to be super rare "PAL" SIMMs, but 1MB SIMMs don't have that limitation. 8MB works regardless of ROMs and MMU setup, and is fine for System 6 and even some stuff up to about System 7.1 or so.

Great info, thanks! I'll get working on the battery components right away. Probably using https://www.digikey.com/en/products/detail/mpd-memory-protection-devices/6S-1-2AA/2077833

You can compare the board revisions here: Rev A, Rev B.

The MMU is the big black chip right above the CPU. The PMMU would be gold and would be labeled MC68851. Yours looks to be the original configuration which came with 2MB, upgradable to 8MB. The 68851 was later offered as an upgrade to allow for more RAM. The PMMU was exclusive to the Macintosh II due to its unique use of the 68020 processor. Later processors had paged memory handling built in. Just a bit of history. 8MB should be plenty for most software from that era. I would definitely upgrade to 8mb.

The Toby card is fine too, you don't need to upgrade unless you have a very specific use case.

Soldering the battery holders to existing leads may actually be more difficult than soldering the through-hole. Like you said, maybe you can practice some through-hole soldering first to get comfy with it. For most of these types of boards, you do need a decent iron that can supply enough power to heat up the ground plane. There are other options - for example, I believe I've seen some pictures of people using a battery pack attached with wires.

Good luck!

Ah, so I have a Rev A without PMMU. That's fine. When I dig out my keyboard and mouse I'll keep an eye out for that old anti-static bag of RAM I used to have. There may well be some 1MB SIMMS from old Macs in there. I have a good Weller PES50 soldering station; but I think I need a larger tip. The one I have is extremely fine and I'm not sure it will push enough heat to warm up the large ground plane.

I was able to use the Weller at 600 to desolder the shield from my C64; but I had to kind of use it side-on. Maybe I can order more tips from Digikey with the battery holders. Aside: My other projects are restoring my first and second computers; VIC-20 and C64 from 11yo and 13yo...these I have the originals of. So now I have a little museum of 11, 13, and 16yo geeky me.

Does anyone have any links to a good video or details on power supply re-cap or general risks? I saw someone testing a Macintosh II on YouTube that did a bang and started smoking; and now I am scared haha.
 

Phipli

Well-known member
Great info, thanks! I'll get working on the battery components right away. Probably using https://www.digikey.com/en/products/detail/mpd-memory-protection-devices/6S-1-2AA/2077833
Make sure you check the lead spacing. I haven't looked into that part, but at one point I ended up with ones that didn't fit.

Don't dismiss entirely just putting the same batteries back. The originals lasted 35 years.

I'm not in the US so it is tricky to find US listings, but for example :

 

ObeyDaleks

Well-known member
Those look right to me. The data sheet says 30mm spacing, which should be about right. I didn't buy mine, I just stole them off some donor boards.

In my case, the holes were slightly too close to make the two holders sit cleanly side by side, so I had to bend the leads slightly sideways to make them fit. The holders also usually have a plastic nub on the bottom that needs to be cut off. Lastly, when soldering, make sure you push them very tight and flush with the board. You don't want them sitting above the surface.

I would leave the PSU alone if it’s working. If, as you said, you’re not comfortable with soldering, a PSU recap might be a doozy. And a chance of it failing catastrophically and destroying your Mac is very low, imho.
 

markkrueg

Member
Those look right to me. The data sheet says 30mm spacing, which should be about right. I didn't buy mine, I just stole them off some donor boards.

In my case, the holes were slightly too close to make the two holders sit cleanly side by side, so I had to bend the leads slightly sideways to make them fit. The holders also usually have a plastic nub on the bottom that needs to be cut off. Lastly, when soldering, make sure you push them very tight and flush with the board. You don't want them sitting above the surface.

I would leave the PSU alone if it’s working. If, as you said, you’re not comfortable with soldering, a PSU recap might be a doozy. And a chance of it failing catastrophically and destroying your Mac is very low, imho.

Sounds good. Thanks again for the advice.

I'm trying to get my Zip 100 drive to boot it with 6.0.8 at the moment.
 

volvo242gt

Well-known member
Looks to be a decent machine. Another option for the battery situation would be to get a couple AAA battery holders. Attach them to the front of the case, then connect them to the clipped leads on the board where the batteries are currently located. Gets the batteries off the board itself and allows you to use something more common.

I'm using one of these in my Apple IIgs. When I get another Mac II, I'm thinking about getting two more, then extending the leads so they're long enough to reach the front panel of the machine.

Hard drive-wise, I'd be tempted to grab something in the 230-250MB range. Enough space to handle System 6, plus a bunch of games and other programs that you'll be running on it. Use a Mac SE hard drive bracket to mount said drive in place. You can also add a second floppy drive, if desired...
 

hauke

Active member
Great info, thanks! I'll get working on the battery components right away. Probably using https://www.digikey.com/en/products/detail/mpd-memory-protection-devices/6S-1-2AA/2077833

Ah, so I have a Rev A without PMMU. That's fine.
The German magazine c't had a project for a small 68020-68030 adapter board, which might be a more viable alternative to finding a PMMU chip:

Hochsitz Adapter für 68030-CPU in 68020-Sockel Holger Zimmermann, Carsten Meyer Projekt, 68020/030-Adapter, PAK68/2, 68000, Prozessor-Austausch c't 7/93 S. 202 (cm)

I gave my issues away a few years ago, but others might be able to provide a scan.
 

markkrueg

Member
Looks to be a decent machine. Another option for the battery situation would be to get a couple AAA battery holders. Attach them to the front of the case, then connect them to the clipped leads on the board where the batteries are currently located. Gets the batteries off the board itself and allows you to use something more common.

I'm using one of these in my Apple IIgs. When I get another Mac II, I'm thinking about getting two more, then extending the leads so they're long enough to reach the front panel of the machine.

Hard drive-wise, I'd be tempted to grab something in the 230-250MB range. Enough space to handle System 6, plus a bunch of games and other programs that you'll be running on it. Use a Mac SE hard drive bracket to mount said drive in place. You can also add a second floppy drive, if desired...

Thanks! It’s not a museum piece, but it’s perfect in my eyes :)

This AA battery idea intrigues me because I think I can find all the parts here at home. AA battery holders are common and I think I have some clip wire connectors. It might be a good idea as a temporary solution until I make an order from Digi-Key. It would be more efficient to wait until I have a number of things to buy, as shipping is killer. Also I have been spending way too much on my hobbies lately and should really give the credit card a break for a couple months (wife is angry at me). Use what I have first.

Good idea on drive. I think I will make today‘s mission to go through my stack of drives and find a quiet running one in the 250 range. It would be amusing if I found one that already had a compatible OS installed, as many probably came from my days fixing Macs professionally. I feel like I’ve lost so much of what I knew; but a little is coming back. There was a time when I went through the full Apple certification on this era machine, but of course that was mostly just about swapping components and running diagnostics, no soldering required haha. I did have to cut resistor leads on thousands of classic Macs for RAM upgrades though.

Eventually I want to build a piSCSI as the idea of using that as my main drive and also network adapter with the ability to remotely add files to the machine is very cool. Plus parts should only be $30 or so and I have a spare Pi.
 

markkrueg

Member
The German magazine c't had a project for a small 68020-68030 adapter board, which might be a more viable alternative to finding a PMMU chip:

Hochsitz Adapter für 68030-CPU in 68020-Sockel Holger Zimmermann, Carsten Meyer Projekt, 68020/030-Adapter, PAK68/2, 68000, Prozessor-Austausch c't 7/93 S. 202 (cm)

I gave my issues away a few years ago, but others might be able to provide a scan.
Thanks! I love this idea! I’m not sure I want to spend a lot on aftermarket upgrades for this machine, as I’m trying to keep it like my original. But building something myself could be a lot of fun, and possibly inexpensive. I’ll do some digging to try to find the article. And if I can find some RAM laying around it could be a path to a nice modernization of the II. I found a bag of SIMMs yesterday and need to go through them all.

I also found a box in the furthest reaches of the back of my garage containing these:

IMG_7984.jpeg
And also one more mouse. Unfortunately I haven’t found the short ADB cable that connects the two halves of the keyboard but any ADB will do if I don’t find it (and I found a couple spare cables as well).
 

markkrueg

Member
Today I cut the 36 year old Varta batteries off the board and temporarily replaced them with AA battery packs. Initially I clipped the AA packs on but decided it was too janky and soldered them with shrink wrap. My Macintosh II is booting 6.0.8 and 7.5.5 with new batteries!

The amazing thing is BOTH Varta batteries still registered more than 3V (which is their nominal voltage). How is this possible after 36 years? I made a video when I removed them to show the voltages:


IMG_7994.jpeg

I went with temporary battery packs because total cost to me was $5.42 (delivered) from Amazon. My wife saw me placing the order for new Vartas and proper battery holders and put a stop to it. Total with shipping was about $40 (mostly shipping). This should get me by for a few months and will let me safely use my machine.

 
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markkrueg

Member
Today was a big day for my Macintosh II:

- Installed 8MB RAM from MemoryMasters
- Connected a PiSCSI using an old Raspberry Pi 2 board as a SCSI drive
- Moved it from the workshop into the house proper

IMG_8018.jpgIMG_8019.jpg

I know the sticker might be upsetting to some; but my Mac once had a large number written across the front and I wasn't able to completely remove it. This PiSCSI sticker covers the blemish nicely; and I am REALLY loving the PiSCSI. It makes disk management (and hopefully networking also) painless. It can simultaneously emulate any number of disks, and was very inexpensive as well.
 

3lectr1cPPC

Well-known member
Not uncommon at all to see those VARTA batteries still good. They aren't the same NiCad or NiMH ones used in PCs and laptops - their Lithium ones last. Still can leak though so yeah get em out.
 

volvo242gt

Well-known member
Today was a big day for my Macintosh II:

- Installed 8MB RAM from MemoryMasters
- Connected a PiSCSI using an old Raspberry Pi 2 board as a SCSI drive
- Moved it from the workshop into the house proper

View attachment 56986View attachment 56987

I know the sticker might be upsetting to some; but my Mac once had a large number written across the front and I wasn't able to completely remove it. This PiSCSI sticker covers the blemish nicely; and I am REALLY loving the PiSCSI. It makes disk management (and hopefully networking also) painless. It can simultaneously emulate any number of disks, and was very inexpensive as well.
Looks good. I'd add a period correct Apple Computer sticker somewhere on it as well.
 

markkrueg

Member
Over the last few weeks I restored my Apple Extended Keyboard II and purchased and restored an AppleColor High Resolution RGB display. I also swapped the fan in my PSU to reduce noise, My Macintosh II Is working very well now, and I’m so happy.
 

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