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Tokamac Nubus card? Need help identifying
Hi all - I just acquired this card from an auction. I don’t know much about older Mac hardware, only that they are nostalgic to me because I used an SE in high school. The card is a Nubus card I think. It has a 68040 33mhz chip. It is marked Donoho Design Group, 1992. I believe Fusion changed their name to Donoho in the early 90s? Thank you for any help! Posted by: Capt_Redbeard on 2025-12-17 20:12:30
I think you may have just found the only 68040 accelerator for IIfx. Only explanation I can come up with for that particular inline arrangement of a 120 pin PDS connector and 96 pin nubus connector. That might be the only card confirmed to exist either, as far as I'm aware it's not even been pictured before. Going off that picture, it has 128K of cache onboard and it seems to be set up to run both nubus and PDS. Maybe something to do with the weird bus segmentation of the IIfx. Miiiiight be clonable if those are FPGAs hiding under the labels as U43 and U44 look like configuration PROMs. More pictures and some of the rear might shed a little more light. Nice find! Posted by: zigzagjoe on 2025-12-17 20:45:29
Congrats you found a rarity, IIfx Tokamac 68040/33. Now you need to find a IIfx motherboard with a modified UK7 Pal chip to run it on (busmastering is needed and Apple shipped the IIfx without it working correctly). I have the drivers stored here somewhere. Posted by: Unknown_K on 2025-12-17 21:00:50
As @Unknown_K already said the card is useless if you don't have a modified Macintosh IIfx logicboard with the PAL at UK7 replaced by Donoho/Fusion. There's only one person I know of that has one of those logicboard and I never got a reply from them when asking if I could get my hands on the logicboard to reverse engineer the replacement chip. Posted by: Bolle on 2025-12-18 02:06:12
I think you may have just found the only 68040 accelerator for IIfx Except the Rocket? Posted by: cheesestraws on 2025-12-18 05:26:25
Except the Rocket? "native" PDS accelerator was the intent but I start dropping words when posting while tired 😛 "it seems to be set up to run both nubus and PDS" was also supposed to be it can bus master on both nubus and PDS, to work around segmentation issues of the IIfx architecture. So it would talk to nubus cards directly from the card rather than going via IIfx LB. Posted by: zigzagjoe on 2025-12-18 06:33:42
As @Unknown_K already said the card is useless if you don't have a modified Macintosh IIfx logicboard with the PAL at UK7 replaced by Donoho/Fusion. There's only one person I know of that has one of those logicboard and I never got a reply from them when asking if I could get my hands on the logicboard to reverse engineer the replacement chip. Is the replacement very hard to find these days? Posted by: LaPorta on 2025-12-18 08:01:25
seems there's only one known replacement PAL in existence so I'd assume it is rather hard to find Posted by: finkmac on 2025-12-18 08:25:50
Is the replacement very hard to find these days? PAL is a programmable logic chip, if someone got a hold of this particular Donoho PAL they could read out or reverse engineer the logic it was programmed with and write that to new PALs or GALs. But I guess the person who owns this special IIfx logic board is a total douchecanoe for not donating it to science Posted by: luRaichu on 2025-12-18 08:32:50
Wow, extremely lucky. Would love to get one of those even without the required motherboard. It's one of those things that I'd hang onto just incase the motherboard shows up. Congrats. Posted by: olePigeon on 2025-12-18 08:49:40
seems there's only one known replacement PAL in existence so I'd assume it is rather hard to find Yeah. I've been scouring eBay off and on for probably the past 20 years checking II, IIx, and IIfx auctions to take a peak at the motherboards. I figure it's just as likely a IIfx-upgraded II or IIx would be a likely candidate for a Tokamac as any IIfx, especially if the owner is trying to stretch every dollar and upgrade. The problem is convincing the listers to send you pictures of the motherboard, especially when it's a e-waste company that doesn't show the inside of the computer. Posted by: olePigeon on 2025-12-18 08:52:56
But I guess the person who owns this special IIfx logic board is a total douchecanoe for not donating it to science I would think it's more a language barrier kind of thing in this case. The fellow is a member here as well and they're located in Japan. I think they don't speak English at all because, so I'm not sure they did understand anything of what I messaged them. Posted by: Bolle on 2025-12-18 12:27:44
@Bolle I presume you already reached out to JDW? He speaks Japanese. (I feel like we've already discussed this several times before. 😛) Posted by: olePigeon on 2025-12-18 14:27:08
Perhaps a dumb question, but you know what they say about that... @Capt_Redbeard - you say you acquired the card in an auction... was there a Mac IIfx also in that auction at the same time - or previously on that auction site? Which auction site / provider was it? Posted by: mg.man on 2025-12-18 14:57:07
Perhaps a dumb question, but you know what they say about that... @Capt_Redbeard - you say you acquired the card in an auction... was there a Mac IIfx also in that auction at the same time - or previously on that auction site? Which auction site / provider was it? @Capt_Redbeard This is a really good point. It'd be well worth it to contact the seller to see if they have the computer that this card belonged to. You might strike gold twice. Posted by: olePigeon on 2025-12-18 15:13:59
@Capt_Redbeard This is a really good point. It'd be well worth it to contact the seller to see if they have the computer that this card belonged to. You might strike gold twice. Good point all - If I would have known this was a thing then I would have checked to see if there was a IIfx listed. I just looked at the site today but since the auction is over I can’t go back and look 🙁 Posted by: Capt_Redbeard on 2025-12-18 17:58:08
Can this card be cloned, given it’s rarity? Posted by: TimHD on 2025-12-18 20:31:32
To clone the card, you need to know it works, and how do you do that? Posted by: Unknown_K on 2025-12-19 00:20:19
Can this card be cloned, given it’s rarity? Well, this is the problem @Bolle alluded to above - you can't really clone the card without also cloning the modification to the IIfx LB, and that isn't available for cloning. As @Unknown_K says, the cloner wouldn't be able to check that their clone actually was correct or worked unless the modification was also available for cloning and it appears not to be. Posted by: cheesestraws on 2025-12-19 00:38:26
When I snagged my card ages ago, I directly contacted one of the designers who had the drivers for the card but not the data for the GAL. From what I recall the control panel either hung up or did nothing. I have no idea if my card works, but it's nice to have anyway. Posted by: Unknown_K on 2025-12-19 10:39:38