More than one Nubus card in IIsi Nubus adapter

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Joined: Feb 23 2007
Posts: 4

Is it possible?
Is there a such adapter?
I have not looked any nubus mobo in detail yet, but is it possible to just duplicate the nubus slot with a cable similar to SCSI or IDE cable?

Any ideas?

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Eudimorphodon's picture
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Joined: Dec 21 2003
Posts: 1204
More then just a cable

The simple answer is of course an expansion chassis, something like this. (A company called "Second Wave" apparently made a four slot version specifically for the IIsi that plugged in in place of the Apple NuBus adapter)

Lacking that, well... NuBus isn't simply a dumb "backplane" sort of bus like, say, ISA or PDS. A NuBus card depends on per-slot decoders to assign it a memory address and perform some simple arbitration functions. To add additional slots to the existing Apple adapter would mean extending the "generic" parts of the backplane and adding a little chunk of glue logic to decode the additional slot(s). The only way to really do it cleanly would be to make a new circuit board based on the original but with additional slots, desolder (or duplicate) the PDS to NuBus bits from the old board, and transfer them to the new whilst adding the necessary per-slot decoder logic. Anything involving cables and soldered hackery would be electrically very "noisy" and likely to crash the machine and/or damage the adapter cards.

Obviously the smarter choice at this point is to buy/beg/steal a NuBus Mac with more slots built-in.

--Peace

Oddball's picture
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Joined: Apr 4 2009
Posts: 93
The Duo Dock NuBus riser coul

The Duo Dock NuBus riser could give you some clues about how to go about getting 2 slots out of the IIsi adapter.

Is there any chance you, or anyone out there, cuold scan both sides of the IIsi NuBus adapter card for the NuBus Mafia project. IIRC it has the NuBus controller ICs on board & I'd love to get a look at it.

I just got a scanner/printer copierfor my new netbook, I'll try to send in scans of the DuoDock riser once I've got the scanner figured out.

jt

ps: finally back online, mobile only so far.

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Joined: Feb 23 2007
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Not a scan but photoes I'll t

Not a scan but photoes I'll try

Oddball's picture
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Joined: Apr 4 2009
Posts: 93
Solder Side Needed

There's a good scan of the component side of the IIsi NuBus riser board in the NuBus Mafia archive here on 'fritter, but I couldn't find the solder side. I haven't looked for the DuoDock NuBus Riser there as yet, if you can't find it, let me know and I'll try to figure out how to use the new scanner/copier/printer/fax I picked up yesterday for my NetBook: HP Mini/PowerBook Duo replacement.

jt

ps: might be a good idea to shoot the component side too, just in case yours is a different rev than the one posted here.

Oddball's picture
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Joined: Apr 4 2009
Posts: 93
Snagged the lil' sucker on eBay . . . .

. . . but I haven't had time to even open the package . . .

. . . and I'll bet I've got another one stashed away somewhere from a previous lifetime. :Smile

IIRC there was a two NuBus Slot riser board posted on eBay a while back. Dunno what it was actually for, but it's SURE to have the additional curcuitry to compare for the lack thereof on the IIsi Adapter/Riser.

jt

Oddball's picture
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Joined: Apr 4 2009
Posts: 93
Snagged the lil' sucker on eBay . . . .

. . . but I haven't had time to even open the package . . .

. . . and I'll bet I've got another one stashed away somewhere from a previous lifetime. :Smile

IIRC there was a two NuBus Slot riser board posted on eBay a while back. Dunno what it was actually for, but it's SURE to have the additional circuitry to compare for the lack thereof on the IIsi Adapter/Riser.

jt