Noob SE/30 question: how do you attach the backplate for a PDS card?

[bigmessowires]

The opening in the back of my SE/30's case is just a rectangle. There are no screw holes, tabs, or other obvious ways to attach the backplate for an SE/30 video card's monitor connector. Is my SE/30 missing a piece? I feel like this is an intelligence test and I failed it.

 

[LaPorta]

Normally, there are small plastic tabs on the cover itself; there is nothing in the case to secure it. The chassis of the machine, however, should have a metal riser that fits right there for you to secure the port faceplate to. Is your SE/30 missing that?

EDIT: This guy circled in the photo:

 

[bigmessowires]

Yes, mine doesn't have that riser piece on the frame. I seem to recall encountering it years ago, not knowing what it was, and removing it since it was in my way. Ouch.

Anybody have a 3D model for a printable replacement? Or a riser from a dead SE/30's frame they'd be willing to sell?

 

[jajan547]

Yes, mine doesn't have that riser piece on the frame. I seem to recall encountering it years ago, not knowing what it was, and removing it since it was in my way. Ouch.

Anybody have a 3D model for a printable replacement? Or a riser from a dead SE/30's frame they'd be willing to sell?

Yep can print them here:

Macintosh SE Addon Bracket (Apple P/N 805-0939-B NATD) by GGigabiteM

This model is a re-creation of the metal addon slot bracket used in the Macintosh SE and a few other Compact Macintosh systems of the late 80s and early 90s. An original metal bracket was used to get the measurements for this part. The only major change between the metal original and this model...

www.thingiverse.com

 

[LaPorta]

Nice! I sold an extra a few years ago; it was the last free one I had. Hope that plastic one gets you going.

 

[jajan547]

Nice! I sold an extra a few years ago; it was the last free one I had. Hope that plastic one gets you going.

If not I have a spare case I can pull one from if @bigmessowires wants a metal one.

 

[bigmessowires]

If not I have a spare case I can pull one from if @bigmessowires wants a metal one.

Thanks, that might be best if you're willing. I don't currently have a 3D printer and the model notes "You may have to experiment with rafts and supports to get a good quality print." Having a 3D part is awesome and I'd definitely try that first if I were more literate at 3D printing.

 

[jajan547]

No worries PM me and we'll get one your way

 

[bigmessowires]

Thanks to @jajan547 I now have the coveted bracket. What I apparently don't have are the right screws needed to attach the bracket to the SE/30 chassis frame. I went through a huge collection of assorted screws with different diameters and thread pitches and none seem to fit.

Can anybody offer a clue what the correct screws look like? As far as I can tell, it's supposed to thread into a tapped hole in the chassis, rather than slide through the chassis and be secured by a nut on the other side? Is the thread fine pitch or coarse? Any guess if it would be an imperial size or metric? I think nearly all my assorted screws are imperial. I tried stealing screws out of other Mac hardware I have lying around, but none seem right.

 

[jajan547]

Hey there I’m so sorry bout that. I didn’t know you needed the screws too. I can send the screws you need too just PM me. I went through my service guides and here’s all I can find:

 

[s_pupp]

4-40 works with my SE/30
The screw is about 9mm long

 

[bigmessowires]

No worries, I'd assumed it was a common screw. After lots of experimentation, I discovered it's the same as the screw that attaches the ground wire from the power supply. I'm going to bring that screw to the hardware store and use it as a reference to get more.

4-40 works with my SE/30

Huh, I'm positive that some of my stash are #4-40. Actually, my ground screw (which fits) looks different than the screw you pictured. The thread is more coarse:

 

[bigmessowires]

I think maybe it's these? https://www.amazon.com/Stainless-Phillips-Sheetmetal-Listing-Degrees/dp/B07CRP9GQL?th=1

 

[Phipli]

No worries, I'd assumed it was a common screw. After lots of experimentation, I discovered it's the same as the screw that attaches the ground wire from the power supply. I'm going to bring that screw to the hardware store and use it as a reference to get more.



Huh, I'm positive that some of my stash are #4-40. Actually, my ground screw (which fits) looks different than the screw you pictured. The thread is more coarse:

View attachment 65160

That is some kind of self tapper you have. Make sure it isn't meant to be a metric machine screw of some kind. I can't tell which screw you mean exactly, a picture would help.

Putting a self tapper in a machine screw hole will chew up the hole horribly.

 

[s_pupp]

No worries, I'd assumed it was a common screw. After lots of experimentation, I discovered it's the same as the screw that attaches the ground wire from the power supply. I'm going to bring that screw to the hardware store and use it as a reference to get more.



Huh, I'm positive that some of my stash are #4-40. Actually, my ground screw (which fits) looks different than the screw you pictured. The thread is more coarse:

View attachment 65160

The coarsely threaded ground screw will fit in the finer threaded bracket screw hole, but it does not belong there, and will distort the hole in the process. My screw gauge kit does not have a gauge that fits the course ground screw.

The picture below shows that the ground screw has coarser threads.

 

[Phipli]

The coarsely threaded ground screw will fit in the finer threaded bracket screw hole, but it does not belong there, and will distort the hole in the process. My screw gauge kit does not have a gauge that fits the course ground screw.

The picture below shows that the ground screw has coarser threads.

Yeah, the finer thread there looks like a metric machine screw. Apple like M3.5 screws which can be tricky to find. If someone can clearly tell me which screw it is, I can measure on from my machine.

 

[s_pupp]

I was under the impression Apple used metric screws, but the bracket screw does not fit any of my metric screw gauges. It does fit the 4-40. It falls out of an M3.5 gauge, and won’t go into an M3.0-0.5 or M3.0-0.35.

Pic of the screw fitting perfectly in the 4-40 gauge, which itself fits perfectly into the bracket screw hole is below.

If the bracket screw hole was damaged by the ground screw, the 4-40 screws that were attempted might not fit.

 

[bigmessowires]

If someone can clearly tell me which screw it is, I can measure on from my machine.

It's the three screws that attach the PDS card bracket to the rest of the frame, circled in red in the photo here: https://68kmla.org/bb/index.php?thr...e-backplate-for-a-pds-card.45756/#post-507475

 

[bigmessowires]

Pic of the screw fitting perfectly in the 4-40 gauge, which itself fits perfectly into the bracket screw hole is below.

OK, I will get some more 4-40 screws and try again. I'm almost sure that some of my mixed screw collection are 4-40, but maybe I'm wrong.

I tried to be gentle when testing different screws, not applying much force so as to avoid damaging the threads in the frame. But I suppose that's no guarantee.

Thanks for the measurements!

 

[bigmessowires]

Extreme close-up of @LaPorta's earlier photo looks like the coarse-threaded self-tapping screw I also pictured, and not like a 4-40. Look at the thread pitch: