Project30 - IIsi NuBus adapter in SE/30 trials - take 2

[Trash80toHP_Mini]

This one I started working on two years ago and have been procrastinating for most of it. If you wanna check out the false starts, sudden stops, feeling my way toward a workable physical solution and the utter silliness of installing everything in my ZipMacPlus™ as a sleeper, check out Project30. Otherwise, I'm posting the highlights of development and the final physical configuration.

I began by drawing up the outline of the "Largest allowable Macintosh SE/30 expansion card" and left lots of room around the edges making up the Plexi chassis for the prototyping testbed:



The white grease pencil indicates Apple's requirements, the clear Plexi surround would be mine! HEH!



Pretty sure all of these Pics show the ZipMacPlus™ front bezel and Zip Drive over the SE/30 FDD cage, which would have become the HDD cage.

View attachment 11111

Doesn't matter, the twin NuBus Slot configuration for the SE/30 version is exactly the same, but the HDD mounts over the FDD cage.

View attachment 11112

I laid out the components for the final spec out in case this hack actually goes the distance. Juuuust enough room, maybe.



These are the recent developments. Using one of the crazy EuroDin 96 extension cables olePigeon found, I was finally able to contort the NuBus adapter and slot breakout into this unlikely setup for the Project30 testbed.

View attachment 11114

This view shows a single LittleRedRadiusPixelRocket™ in what would be the top of two NuBus Slots if/when the TWO SLOT IIsi Nubus Card hack . . . bears fruit. As in the pics above, the backplane plate(s) of the NuBus Card(s) sit a distance away from the back of the bucket. This allows jumper cables from any given card installed to terminate in connectors mounted on an SE/30 breakout panel in the usual IIsi/SE/30 manner.. The VGA Adapter for a VidCard could be mounted behind that firewall so a VGA cable could be hooked up right there on the backplane instead of one or two inches behind the Mac on the adapter.



This is a profile view of the assembly as it stands. The IIsi NuBus Adapter is mounted on the outside of the chassis, that was the only way to get things jury rigged for the testing phase with parts on hand. Right now the Plexi chassis is bolted to an SE/30 NIC and the Chassis attachment points. It all fits just so, but I have to explore a few possibilities for the NIC's functional replacement.



I love the deliciousness of this kluge! I had to spin the NuBus connection or the PDS connection 180 degrees to mount the cards so they're keyed correctly and facing in the proper direction, hopefully while preserving a straight shot for the PDS extension on a future PCB incarnation. Luckily, choosing the NuBus extension cable just barely worked out. Check out how unwieldy the Male end of that cable is, looks about three stories tall!



There are several levels to test for these components on the IIsi first and then on the SE/30, one step at a time to make sure all the connections function as they should on one machine or the other.

Meanwhile, I need a working SE/30 board. I'll try to get mine straightened out, but I think I may need to do some kind of trade for one. Lots of wire wrap connector and parts expenses coming up soon. If someone wants to donate troubleshooting my board to the cause, that'd be wonderful, there's just so much time, money and sanity to go around. :

 

[techfury90]

Hooooly crap, where'd you find that extension cable? This is very relevant to my hacking plans.

 

[techknight]

Since its standard eurocard stuff, I can only assume lab equipment, test equipment, etc suppliers have stuff like that. 

Problem I would be worried about is tons of noise and reflections causing bus contention and failure. 

 

[Trash80toHP_Mini]

The cable's short and NuBus is only 10MHz, so it should be good for testing.

I certainly don't expect to be using NuBus cards in this feasibility testing kluge. All I really need to see is the card's DeclROM reporting in to Slot Manager that there's a NuBus card installed in slot $9 and what it is. Hopefully the 2 Slots in a IIsi hack will work out and the SE/30 will also see a NuBus card in slot $A if/when I get past the first hurdle..

LOTS of incremental testing needs to be done on the IIsi and then I'll need to find a working SE/30 board.

 

[Trash80toHP_Mini]

 

[jimjimx]

Are you looking for the PDS pinouts? 

I found them at this page, and at the bottom it says

"Additional information may be found in the the Motorola 68000 manual."

http://www.ccadams.org/se/pinouts.html

edit. Let me know if there is anything I can do to help, or anything I can look for.

 

[Trash80toHP_Mini]

Thanks for the offer of help, jj. It was much appreciated then as it is now, but I've been a bit busy.

I was indeed checking pinouts for those signals between the IIsi (top) and SE/30 (bottom) so I uploaded the pic here to go over it at work. So of course I grabbed the second edition instead of the third of DCaDftMF by mistake and wasted a bit of time determining that they were the same. 3e shows a single diagram for the two and says flat out that they're the same, though with the caveat that they handle memory calls using different signals. This turned out to be important. [] ]'>

The biggest favor anyone could do to help out with the overall project would be to run down uniserver's diagram/parts list for recapping the IIsi. If that were to be translated into a list of part numbers/quantities for me to easily order up four sets at DigiKey to give it a go that would be awesome! Haven't done a recap yet, but the odds of my killing all four  .  .  . 

.  .  .  anyways  .  .  .  I really need a working IIsi board (or all four!) to sort some issues out in that machine and to act as a "Control Group" for NuBus in SE/30. Not to mention taking some of the risk burden off the shoulders of my single working example of that breed.

BTW: this thread has played out and some serious work has begun in the next: Project30 - IIsi NuBus adapter in SE/30 trials - take 3

 

[demik]

Working link post XenForo migration: Project30 - IIsi NuBus adapter in SE/30 trials - take 3