Mac SE/30 ATX - any takers?

[jonathanschilling]

Hello altogether,

this is my first post on this wonderful forum and I would like to use the opportunity to say a big Thank You to all members sharing their insights into classic Macs.

I was wondering the other day what you guys think about an ATX mainboard, created based on @Bolle's recreated Mac SE/30 logic board, potentially spiced up with some additional circuits discussed in the community.

The standard layout of ATX on-board connectors could be repurposed to some degree for the connections present on the back side of the Mac SE/30:
* parallel port <--> SCSI
* serial port <--> VGA (with converter, see below)
* PS/2 <--> ADB (via S-Video connectors)

In a first iteration, the first ATX slot could be used for the PDS.
Do Nubus adapters exist for the SE/30?
Maybe one could integrate such a circuit in a future iteration of the ATX board, thereby making use of additional slot options in the ATX specification.

An ATX-compatible power supply adapter seems to exist already in this project:

mAcTX - ATX to Classic Macs

Hey all, just wanted to gauge community interest to see if anyone would be interested in an ATX to Mac 10-pin adapter board. I've got a IIsi with a dead power supply (surface mount caps got REALLY bad inside) and @Compgeke and I have been working on an adapter board that'll take any ATX power...

68kmla.org

Also, a screen adapter for converting the Mac SE/30 internal monitor to VGA is available here:

GitHub - guruthree/mac-se-video-converter: Convert video from a Mac Plus/SE/Classic to a VESA VGA signal using a Raspberry Pi Pico

Convert video from a Mac Plus/SE/Classic to a VESA VGA signal using a Raspberry Pi Pico - GitHub - guruthree/mac-se-video-converter: Convert video from a Mac Plus/SE/Classic to a VESA VGA signal u...

github.com

The main purpose of this would be to have a fully open-source (well, as of now except the ASICs used on the Mac SE/30 logic board) computer for which a whole lot of software exists that would actually make it usable for some productive work.

The major showstopper to me is the small B/W display in classic Macs, which would additionally (on top of the VGA adapter) require an add-on video card.
In this regard, two projects on this forum come to my mind:
https://68kmla.org/bb/index.php?threads/building-an-internal-grayscale-card-for-the-se-30.39910/ and
https://68kmla.org/bb/index.php?threads/nubusfpga-hdmi-on-nubus-macs.40760/ (via a NuBus adapter).

I don't have the time to pull this of myself these days, but I would like to put the idea up for discussion and hear what people think about it.

Sorry if this was brought up in another context already. Please feel free to point out related threads.
Any other related thoughts and useful info is of course highly appreciated as well.

Have a nice weekend,
Jonathan

 

[Nixontheknight]

Hello altogether,

this is my first post on this wonderful forum and I would like to use the opportunity to say a big Thank You to all members sharing their insights into classic Macs.

I was wondering the other day what you guys think about an ATX mainboard, created based on @Bolle's recreated Mac SE/30 logic board, potentially spiced up with some additional circuits discussed in the community.

The standard layout of ATX on-board connectors could be repurposed to some degree for the connections present on the back side of the Mac SE/30:
* parallel port <--> SCSI
* serial port <--> VGA (with converter, see below)
* PS/2 <--> ADB (via S-Video connectors)

In a first iteration, the first ATX slot could be used for the PDS.
Do Nubus adapters exist for the SE/30?
Maybe one could integrate such a circuit in a future iteration of the ATX board, thereby making use of additional slot options in the ATX specification.

An ATX-compatible power supply adapter seems to exist already in this project:

mAcTX - ATX to Classic Macs

Hey all, just wanted to gauge community interest to see if anyone would be interested in an ATX to Mac 10-pin adapter board. I've got a IIsi with a dead power supply (surface mount caps got REALLY bad inside) and @Compgeke and I have been working on an adapter board that'll take any ATX power...

68kmla.org

Also, a screen adapter for converting the Mac SE/30 internal monitor to VGA is available here:

GitHub - guruthree/mac-se-video-converter: Convert video from a Mac Plus/SE/Classic to a VESA VGA signal using a Raspberry Pi Pico

Convert video from a Mac Plus/SE/Classic to a VESA VGA signal using a Raspberry Pi Pico - GitHub - guruthree/mac-se-video-converter: Convert video from a Mac Plus/SE/Classic to a VESA VGA signal u...

github.com

The main purpose of this would be to have a fully open-source (well, as of now except the ASICs used on the Mac SE/30 logic board) computer for which a whole lot of software exists that would actually make it usable for some productive work.

The major showstopper to me is the small B/W display in classic Macs, which would additionally (on top of the VGA adapter) require an add-on video card.
In this regard, two projects on this forum come to my mind:
https://68kmla.org/bb/index.php?threads/building-an-internal-grayscale-card-for-the-se-30.39910/ and
https://68kmla.org/bb/index.php?threads/nubusfpga-hdmi-on-nubus-macs.40760/ (via a NuBus adapter).

I don't have the time to pull this of myself these days, but I would like to put the idea up for discussion and hear what people think about it.

Sorry if this was brought up in another context already. Please feel free to point out related threads.
Any other related thoughts and useful info is of course highly appreciated as well.

Have a nice weekend,
Jonathan

instead of ADB to PS/2, they could instead do USB for keyboards and mice

 

[eharmon]

If I remember correctly, an old Outbound was an entirely custom logic board with Plus/SE ROM chips, and they were generally quite compatible clones. So not just practical, but definitely done before.

Adding NuBus back seems imminently possible given the SE/30 was derived from a IIx which had 6 NuBus slots.

A "modern" SE/30 with a ROM SIMM would definitely be a lot of fun!

 

[shadedream]

It's a cool idea, but I think I'd lean towards ITX or maybe mATX if you were trying to add some card clots or something to the hardware. Without additional expansion, I can't think of why one would need a large ATX board and case. But I'm a bit of an ITX weirdo and like small computers.

 

[gheem]

Interesting, I’d be happy to beta test any production candidates and work on a case for the thing……

 

[demik]

In a first iteration, the first ATX slot could be used for the PDS.
Do Nubus adapters exist for the SE/30?

The IIsi NuBus adapters do sort of work.

However, they will be running at 8 MHz which is not standard (early NuBus is 10 MHz) so some cards will not work.

 

[eharmon]

The IIsi NuBus adapters do sort of work.

However, they will be running at 8 MHz which is not standard (early NuBus is 10 MHz) so some cards will not work.

Huh.....that's really interesting as I thought they didn't work at all. Obviously there's physical incompatibility with the SE/30 case, but that presumes a IIsi adapter could sit on top of a passthrough card like an ethernet adapter in a real SE/30 to provide clearance? For a project like this you wouldn't need that, of course.

At any rate, if you could integrate a cloned adapter onto the ATX board, seems like you could easily have 8MHz NuBus if that's the case.

 

[paws]

How about moving all the custom chips to a daughterboard, and then making a replacement daughterboard with a CPLD/FPGA? Then you'd be able to make new Macs.