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Any known caveats with a IIsi?

Nifty950

Well-known member
Wait... a Twosie runs A/UX?! Oh i am so buying that machine! That bit of information made my day. I cant think of anything better in life than running A/UX!
 

MrFahrenheit

Well-known member
Wait... a Twosie runs A/UX?! Oh i am so buying that machine! That bit of information made my day. I cant think of anything better in life than running A/UX!
It does so long as you have an FPU installed. A/UX 2.0.1 and above are supported.
 

MrFahrenheit

Well-known member
Where do i get an FPU? did they come as brand names? Useful search term?

The FPU is installed in a socket, which is contained on an adapter board.

Some adapter boards have the socket, some don't. Some come with the FPU pre-installed.

Like this one:

1651021491889.png
 

Danamania

Official 68k Muse
A IIsi resto is my current project, and it's up and running happily - I recapped its PSU last weekend, which went a lot quicker than expected (I haven't done many recaps, and it was a horrid mess beforehand). It was all through-hole except for the daughterboard SMD caps, which were just a little fiddly. The PSU was *wet* over most of its main board surface with capacitor goo. After doing that, the logic board booted happily, though with sound at about 5% maximum. A logic board recap fixed the sound, and now it's next to me turned on doing busy little system 7.1 things.

This one was overclocked to 25Mhz by its original owner in the 90s, and still is. It makes very little difference, but still it's nice. There's also 4x16MB SIMMs from a Q950 I picked up 20 years ago. It has 65MB RAM and a 40MB HD, which is just daft but amusing. Original 40MB Conner still works, too, and relatively quietly!

In the pic: 7.1 on the IIsi, connected to a Quadra in the other room (Storage), Synology elsewhere in the house (Ankylosaur) via AppleShare IP, running ssheven into my iMac with irssi, word in the background, and netscape hiding there at the bottom.

ssheven_iisi.jpg
 

beachycove

Well-known member
I’d personally recommend something like a Quadra 650 for A/UX, which is also a vastly more robust and expandable machine generally. A IIsi will run A/UX, but it will be kind of slow. Where a IIsi really shines in my view is running System 6, with a Nubus video card and a decent monitor — just my view, of course — but the little thing runs it like greased lightning.

As for the IIsi adapter with FPU, generally an FPU is included on the IIsi PDS Nubus adapter. Those are easily found, and so need not be remade.
 

mattsoft

Well-known member
have there been any projects to remanufacture these boards?

I have a spare FPU board for the IIsi. If you end up buying one, PM me and you can have the FPU board for the cost of shipping, assuming you're in the U.S. it's re-capped and works great.
 

volvo242gt

Well-known member
First color Mac I owned was a IIsi (two-sigh, btw). Not a bad machine, but the IIci that eventually replaced it was a much better machine. Didn't have to choose between a PDS accelerator, a network card, or a video card (if you want more than 640x870 at 16 colors or 640x480 at 256 colors, you'll need a video card on either a IIsi or a IIci). Instead, I could do all three, plus have an extra card in another slot.

One of the issues I had with my original IIsi was with the speaker contacts. Lots of built-up gunk on them, so the speaker would randomly go silent, as well as the power LED shutting off at the same time. Another issue was with the cooling fan. Same kind of contacts.
 

joshc

Well-known member
The IIsi is a nice Mac but it's a nice slow one, the aforementiond trick with disk cache to offset the usage of slow RAM for the onboard video helps, but you'd really want an accelerated QuickDraw NuBus video card in there to get better graphics performance + higher resolutions (I think the IIsi onboard video is just 640x480). You only have one expansion slot in a IIsi, and it can't take full height NuBus cards, you need the PDS->NuBus adapter which is not easy to come by.

Also, as mentioned, A/UX is going to be fairly slow on it. Get something with a 68040 processor instead - like a Quadra or Centris 650.

The other issue is lack of Ethernet of any kind, whereas most 650s have onboard AAUI Ethernet.

No FPU by default either as you've seen, but you would also get around that by purchasing a 650 instead as a full 68040 has a built-in FPU.

Just a few things there to think about - if I was spending $300 on a machine, I'd really be going for a 650 not a IIsi. You'd also get a built-in CD-ROM drive.

And one more thing... a 650 logic board does not need recapping because Apple used tantalum capacitors from the factory in those.
 

volvo242gt

Well-known member
All the aforementioned points, plus the Centris 650 is frequently less than a IIsi, price-wise. Then, there is the dedicated VRAM for the video circuitry, and the ability to run a 640x480 monitor at 16-bit color, or a 21" monitor at 8-bit color. The 650s with an FPU are the ones with 8MB of RAM and the AAUI port for ethernet. The 4MB Centris and Quadra 650 machines use the 68LC040 processor.

Specs on the Centris 650: https://everymac.com/systems/apple/mac_centris/specs/mac_centris_650.html

For the Quadra 650, the differences are a 33MHz '040, and a manual inject floppy drive, instead of the older auto-inject drive.

Personally, I wouldn't go for a IIsi. It really isn't much better than an LCII, except for the fact that, yes, it can go to 65MB, and, with an adapter, can use either SE/30 PDS cards, or a Nubus card. It then has the inferior VampireVideo, whereas, at least the LC series has VRAM.

If you must have a pizza box Mac, get a Centris or Quadra 610. Still kinda limited, expansion card-wise, but, at least has an '040 chip, and the ability to use a built-in CD-ROM drive.
 

mikes-macs

Well-known member
Reports of A/UX only working with specific Ethernet Adapters. There should be a list of compatible Ethernet Adapters that will work with A/UX in a Mac IIsi somewhere here.
 

cruff

Well-known member
BTW, if you go the Quadra route to run A/UX, don't get a 631 or other model that has an IDE drive instead of SCSI. A/UX doesn't support IDE drives out of the box. Not sure if anyone ever made a mod to A/UX to support one.
 

MrFahrenheit

Well-known member
BTW, if you go the Quadra route to run A/UX, don't get a 631 or other model that has an IDE drive instead of SCSI. A/UX doesn't support IDE drives out of the box. Not sure if anyone ever made a mod to A/UX to support one.

Its not just the IDE not being supported on those, it’s the video circuitry, too.
 
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