• Updated 2023-07-12: Hello, Guest! Welcome back, and be sure to check out this follow-up post about our outage a week or so ago.

Terrible IIsi

Kouzui

Well-known member
Hello Everyone!

Picked up a IIsi for very cheap the other day (for reasons that will quickly become obvious.)

iisidirt.jpg

Looks a little dirty, but don't worry. It's not dirt.

Inside this machine was some of the worst battery-bomb carnage I've ever seen.
iisigrotesque1.jpgiisigrotesque2.jpgiisigrotesque3.jpgiisigrotesque4.jpg

The "MDU" chip seems to be the primary victim, but everything looks like it got a good helping of battery acid. Just look at those oscillators! They look like a 4-piece nugget from Wendy's! Where's the ranch?

Oh, and the board wasn't the only victim.
floppyrust.jpg
This floppy drive shroud looks like it spent some time on the Titanic. Or, perhaps, this IIsi came from the USS Cyclops?
Needless to say, the metal coating on the inside of the case plastic was completely eaten away.
casecarnage.jpg
This Mac did not come with a power supply. We're simply left to imagine how horrible that thing looked.

But anyways, as I poked around inside the computer and began taking it apart, I didn't come across any ranch to go with the oscillator nuggets.
I did, however, find the culprit behind most of this mess:
culpritMaxell.jpg
It was the usual suspect, a Maxell. But it had an accomplice, as I found a mummified silverfish nearby it:
deadsilverfish.jpg
Interesting to see one of these guys instead of a roach. But you know what they say, "If you have silverfish, you don't have roaches."

After getting everything out, (the fan was a bit of a bitch to undo), I started disassembling things to see what the real state the computer was in.

floppydirty.jpg
Well how about that? The floppy looks incredibly dusty/dirty, but doesn't look ruined! The board side didn't seem to have any corrosion, except on the metal plate-thing around the motor:
maya.jpg
Though maybe I shouldn't get too excited, if all of those stickers are repair tags or something like that. There's like 3 or 4 layered on top of the serial number sticker.
Also, before I actually got to cleaning, I noticed a component was missing:

whereisit.jpg

And after looking around, I actually found it!
peekaboo.jpg
Missing every. Single. Leg. Not very useful, but it feels good to track it down.

Actually, missing legs became a bit of a theme as I cleaned the board. I also washed the case and sanded the rusty pieces of metal, but the main attraction is the Logic board so I'll show you what it came down to.
Whole board before, for reference:
wholeboard.jpg

As expected, the MDU chip took the brunt of the Maxell's wrath, losing most of the legs facing the battery, and a fair amount on the other side where the battery acid flowed.
mdumissinglegs.jpgmissinglegsdestroyed.jpg
Another victim was the ram and whatever these smaller chips are, which were positioned both downstream of the battery acid and beneath the PSU
moremissinglegs.jpg
The ram chips don't appear to be missing legs, but they are corroded to hell and back.
I thought the CPU was a lucky survivor of this carnage, but upon cleanup and closer inspection, one of its legs has indeed rusted away:
cpumissinglegs.jpg

And all through the board, the caps wreaked their own havoc in places the battery couldn't reach.

So, in conclusion, and in my not-professional opinion, if there was ever an example of a "goner" board, this is it. It's fucked. I haven't searched for an MDU chip as I assume it's proprietary (due to saying APPLE on it). At the same time, I still want to do something with it. I've basically got two ideas so far:

- Get a less damaged iisi board and attempt to repair THAT one
- Use the case to make a sweet sleeper PC

What do you guys think? Could I save this thing? I do know about the ATX mods/converters you can do, so I'm not worried about finding or repairing a PSU.
 

superjer2000

Well-known member
I have no advice as that machine seems done and the logic board seems to have minimal useful parts for future uses but…. That was one of the best write ups I have ever read. You need to keep a journal of this stuff and publish it!!
 

Forrest

Well-known member
Looks like the case is OK. You might want to install a Raspberry Pi 4, and download and install PiMega 4. This is an excellent Amiga emulator that runs faster than any real Amiga, and it also includes a fully working Shapeshifter (Mac emulator). You’ll need to buy a licensed Amiga 1200 Kickstart ROM for $10-$20. Details on YouTube at
 

JC8080

Well-known member
The easiest thing would be to just put an old Mac Mini inside the case. Otherwise I think finding a working/fixable logic board and doing the ATX PSU upgrade makes sense.

And yeah... That's the most trashed board I have seen. True carnage.
 

mg.man

Well-known member
That's the most trashed board I have seen. True carnage.
I've seen worse :cry: -
 

ArmorAlley

Well-known member
Clean the board and keep it until you find someone who needs experience in basic soldering. This will be good board to practice on: removing components, adding components and so on.
I was given a damaged Classic board for this very purpose and I can testify to their usefulness.
 

Kouzui

Well-known member
Clean the board and keep it until you find someone who needs experience in basic soldering. This will be good board to practice on: removing components, adding components and so on.
I was given a damaged Classic board for this very purpose and I can testify to their usefulness.
I don't plan on throwing anything away, but I am currently looking into making the IIsi case into my next gaming PC. I'll keep everyone updated if it seems like it will work (the dimensions are really tight).
 

crazyben

Well-known member
If you are interested I have a spare iisi coming in shortly. I can recap and test that it works and sell you.
 
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