Fitting a IIsi Color Pivot card inside an SE/30 - How?

[bigmessowires]

I'm interested in squeezing a IIsi Color Pivot card inside my SE/30. Has anyone else done this, or attempted it? I know the card works electrically but is slightly too big to fit inside the case, and some physical modification is needed. I'd love to know more. Is it just a question of sawing a few millimeters off the "panhandle" where there are no traces? Or is it something more?



Some years ago @Trash80toHP_Mini posted a lot of thoughts about this, but never arrived at a working solution as far as I know. Searching the web I found a couple of people who've apparently made it work, but they're slightly vague about how it's done. Here is one from Reddit:

https://www.reddit.com/r/VintageApple/comments/9xxrzc

They say "the end of the board shaved off so it fits", but there's no clear photo show what was shaved where. From some of this person's other posts, I think they are also using a second PDS card as a riser for the IIsi Pivot card, and it might be impossible to fit the Pivot card without that.

Here is a thread from @tact discussing a IIsi Pivot card in their SE/30: https://68kmla.org/bb/index.php?thr...or-se30-weird-random-grayscale-problem.38354/ They are also using a second PDS card as a riser for the Pivot, and they mentioned needing to remove the pin headers for the slot address jumper because it was hitting the CRT.

Some other old posts have mentioned cutting into the SE/30 frame to make the card fit, but are short on details.

So far I haven't found any examples of somebody using the IIsi Pivot card plugged directly into the SE/30 PDS with a minimum amount of physical modding.

 

[Bolle]

IIsi Pivot card plugged directly into the SE/30 PDS

Nope. Even with cutting the edge off on the end of the card that faces the back of the machine the bucket is still going to bump into the card.
You need another card with a PDS passthrough that also moves the Pivot card slightly towards the CRT, so the back end of the Pivot card fits into the case. Either a DiiMO accelerator with the PDS passthrough on top, a Twinspark or my ethernet/adapter combo cards will fulfill that purpose and position the card so it just about fits.



Here's the unmodified card vs. one that has been modified to fit into the SE/30:


I removed the FPU socket as well just for good measure - it can stay on.
The ID selection jumpers should be removed. In addition I covered the whole area in insulating tape.

 

[Phipli]

I'm interested in squeezing a IIsi Color Pivot card inside my SE/30. Has anyone else done this, or attempted it? I know the card works electrically but is slightly too big to fit inside the case, and some physical modification is needed. I'd love to know more. Is it just a question of sawing a few millimeters off the "panhandle" where there are no traces? Or is it something more?

View attachment 63782

Some years ago @Trash80toHP_Mini posted a lot of thoughts about this, but never arrived at a working solution as far as I know. Searching the web I found a couple of people who've apparently made it work, but they're slightly vague about how it's done. Here is one from Reddit:

https://www.reddit.com/r/VintageApple/comments/9xxrzc

They say "the end of the board shaved off so it fits", but there's no clear photo show what was shaved where. From some of this person's other posts, I think they are also using a second PDS card as a riser for the IIsi Pivot card, and it might be impossible to fit the Pivot card without that.

Here is a thread from @tact discussing a IIsi Pivot card in their SE/30: https://68kmla.org/bb/index.php?thr...or-se30-weird-random-grayscale-problem.38354/ They are also using a second PDS card as a riser for the Pivot, and they mentioned needing to remove the pin headers for the slot address jumper because it was hitting the CRT.

Some other old posts have mentioned cutting into the SE/30 frame to make the card fit, but are short on details.

So far I haven't found any examples of somebody using the IIsi Pivot card plugged directly into the SE/30 PDS with a minimum amount of physical modding.

Looks like people were stacking them on a MacCon 30si an ethernet card with a pass through :

SE/30 hack: MacCon + IIsi Pivot = Fits (sorta...)

Hey guys. I just received a special package from our very own Bolle. It's an Asante MacCon. Thanks again mate! It's looking great. I wanted to add ethernet to my SE/30 but I also wanted color... And as some of you may already know, the Radius IIsi Pivot is electronically compatible with the...

68kmla.org

Trimming just involves cutting back closer to the traces. I've not done it, but I'd probably Dremel, then use a sander to tidy it up.

 

[Melkhior]

I'm interested in squeezing a IIsi Color Pivot card inside my SE/30

Perhaps you could just add a passive PDS adapter so the card would sit in a slightly difference place? Just need to figure out where it needs to be and do a very simple PCB with a pair of DIN connectors. Basically a simplified version of the IIsi adapter; you can find an example in my github (it's KiCad again, sorry ;-) ).

 

[Phipli]

Perhaps you could just add a passive PDS adapter so the card would sit in a slightly difference place? Just need to figure out where it needs to be and do a very simple PCB with a pair of DIN connectors. Basically a simplified version of the IIsi adapter; you can find an example in my github (it's KiCad again, sorry ;-) ).

At 45°?

(Warning, dissimilar path lengths)

 

[Melkhior]

At 45°?

I don't know the SE/30 - an angle might be necessary I suppose?
The second DIN connector would have to be right-angle, not straight, same as the first, unlike in the IIsi adapter; of course.

(Warning, dissimilar path lengths)

Signal propagation in a PCB is very roughly half the speed of light, so you need about 15cm (half a foot) for a 1 ns difference. At 16 MHz, it's unlikely the difference between traces would make much differences. And modern tools make length-matching easy - in fact, my PDS adapters *are* length-matched despite the (just argued in the previous sentence) uselessness of it... It's the "go-faster stripes" of PCBs design

 

[bigmessowires]

Perhaps you could just add a passive PDS adapter so the card would sit in a slightly difference place?

Yes, I'm going to try doing this. Hopefully it won't end in frustration.

You need another card with a PDS passthrough that also moves the Pivot card slightly towards the CRT, so the back end of the Pivot card fits into the case.

Could you tell me which axis you mean by "moves the Pivot card slightly towards the CRT"? If you mean to move it towards the visible screen surface, the front of the CRT and front of the computer, that shouldn't be too difficult. But if you mean move it towards the CRT body, towards the center line of the Mac and away from the plane of the PDS connector, that sounds harder. I'm not sure how that could be accomplished with a passive PDS adapter card - it seems like it would require a second-level adapter at right angles to the first, or something else more complex.

 

[Phipli]

I'm not sure how that could be accomplished with a passive PDS adapter card - it seems like it would require a second-level adapter at right angles to the first, or something else more complex.

Not sure if it is what Bolle meant, but you can step over about a cm by using two 90° connectors (one left handed, one right handed), one on each side of the PCB. Forgive the horror, drawn without reference to the handed-ness of the Radius card, and with an arse cheak on my phone. Apparently.

 

[bigmessowires]

Nice drawing. I see what you mean. Hmm. I didn't realize there are left-handed and right-handed versions of the right-angle connector. This may be more complicated than I thought. I suppose I just need to get the Pivot card and then take some measurements.

 

[Bolle]

Nope, you want to stay in line with the PDS connector on the logicboard. You want to move the card up (enough to clear the metal frame and sit above it) and towards the front of the machine.
Take a look at the existing adapters or the DiiMO accelerator (they all use the same connector layout) and you'll have the perfect position:



Card is moved high enough so to clear the chassis and CRT mounting tabs and just a tiny little bit towards the front of the machine so the trimmed end of the card will sit flush with the back of the case.

 

[bigmessowires]

I wonder if the passive PDS adapter could include a 90 degree turn, so the Pivot card would end up vertical with its panhandle section at the top of the case? That might enable it to fit without needing to shave the Pivot card PCB. @Trash80toHP_Mini mocked up something like this a while back, but never actually built the adapter. Here is his diagram:

 

[Trash80toHP_Mini]

I've looked int redirecting/patching the traces on the panhandle (modifying the connector too IIRC?) so as to shorten it for a good fit. I think I ran across the docs recently. Not as easily done as I'd originally thought, but doable with some logic tracing I think. Let me know if you need an experimental victim/backup board if you go that way. I can loan one to you for that project.

Search my byline for the card, maybe the pics/PDS links are still intact?

 

[Trash80toHP_Mini]

I don't see why I couldn't mount my P33 vertically, connector parallel to the Pivot's passthru. There should be plenty of cubic available for it as it would be positioned far enough back from the wide section of the CRT to fit. Second bedroom/computer/bench/storage room will be set up again over the next month or so! Too many tools from those that built the family farm before the civil war and on to the present along with antiques from there and at least eight cubic feet of slides/pics/negatives made the trip back from FL. Sealing the slab and not having it carpeted takes a huge load off. Then back to hacking!

@Trash80toHP_Mini mocked up something like this a while back, but never actually built the adapter. Here is his diagram:

BGE did a PDS extension cable, that's why I dropped out on this. Here's the front view:

When I get a chance I'll have some AI playtime and build a mockup to see what fits. If necessary, there should be plenty of room to meander the traces if it should prove necessary, maybe even on a two layer board?


edit: looking at it just now I, see no obvious reason the P33/RCPIIsi can't be mounted a bit forward for more clearance from the back wall. Being on a higher plane, they won't interfere with the required chassis mounting bolts. with a non-conductive sticker applied, I can probably make it work with soldertail connectors, eliminating the need for wire wrap sockets for clearance? @bigmessowires thanks for getting the crufty wooden gears between my ears into motion again!

 

[bigmessowires]

Did @BadGoldEagle ever build that IIsi Pivot adapter? I know it was discussed, but I don't think it went beyond that.

Just doing a quick test fit, it looks like there's room to fit an unmodified Pivot card vertically, with a little extra room to spare. There's also plenty of room to shift it forwards or backwards too, if necessary.

What I'm imagining is a simple passive PDS adapter PCB that plugs directly into the SE/30 PDS slot, without relying on an Asante MacCon or any other cards. This PCB would have two PDS connectors with traces running straight between them, and no other components, so it would be as simple as possible. The upper PDS connector would be rotated 90 degrees so that the Pivot card could be installed vertically with its panhandle section pointing down and its section with the empty chip socket pointing up.

Aside from the Pivot card itself, I discovered that the metal Pivot faceplate which contains the monitor connector doesn't fit in the opening in the back of the SE/30 case. It's just a tiny bit too wide. So you'd need enlarge the case opening, or 3D-print a new faceplate, or something else to make it fit.

I have another SE/30 video card, so I'm probably going to set aside this Pivot adapter idea for the time being.

 

[joshc]

I have another SE/30 video card, so I'm probably going to set aside this Pivot adapter idea for the time being.

You are pivoting to another project?