The Macintosh Minus - pi-powered mini Mac Plus clone with 5" CRT display

vorg

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If e-ink could be used without refresh lag, it would literally take over the B&W flatscreen market. But after all these years, the tech hasn't really taken off due to that problem. They've reduced the time required for refreshes down to about 3 Hz, but compare that to 60Hz and higher for normal LCD screens, and you can see why e-ink has serious usability issues for anything outside a basic eBook reader.
They typically can do localized refresh now; so you start with a white background and can make text function like it does normally when typing.

Video is really the only thing you can't make useable now. For what the Macintosh Plus was capable of; I think it could work. Refresh rate is still gonna be faster than most of the processing.

 
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JDW

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They typically can do localized refresh now; so you start with a white background and can make text function like it does normally when typing.

Video is really the only thing you can't make useable now. For what the Macintosh Plus was capable of; I think it could work. Refresh rate is still gonna be faster than most of the processing.

I am aware, but as you know, moving a window around on a vintage Mac multiple times quickly is not too vastly different from a video. And if the window is large and filled with icons, the display wouldn't benefit that much from "localized" refresh.

There's a YouTube video on the following article page which gives you a general idea of what to expect:

Keep in mind that implementation doesn't allow moving around of windows.

I don't mention this to discourage ideas, but rather to merely speak about the technology in a away to keep expectations realistic.
 

vorg

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I understand what you mean, but we're fundamentally talking about a system from the mid 80's. None of them are as usable as a modern computing device. It's about the art/novelty more than anything.
 
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retr01

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Yeah, what we do with our beloved 68k and PPC Macs (and the Apple II series) is for the art, hobby, and straightforward enjoyment that we are entertained with those fun computers. We are like the Atari and Amiga folks in many ways that we know those will not have modern applications, but we could do retro stuff.

I think that includes doing things that weren't done back in the day within the simplicity and limited options of vintage computers. :)

Oh, by the way, @vorg, I mentioned that pocket Mac in a thread I started and made up the possibilities and specs that it could have:

 
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YMK

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Video is really the only thing you can't make useable now. For what the Macintosh Plus was capable of; I think it could work. Refresh rate is still gonna be faster than most of the processing.

Just about any action game is a bad time for e-ink. Think StuntCopter, Dark Castle etc.
 

vorg

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Really working out the details....

I realized the 1MB I have is totally a different fascia than the Mac Plus photos I referenced out of laziness on v1.

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I originally thought it would be cool to have the NFC reader inside the floppy slot so I can put a card in like a floppy, but they only old 1k outside of specialty ones, so that's not going to allow me to actually use it to mount a fake disk, it would have to be a software based linking.

I have a future idea though, that simply consists of a project to learn how to make custom PCBs. Should be super simple, just an "expander" for a normal micro SD card's terminals that I can use to make a scale floppy-sized giant SD card. Obviously I'd need to design a receiver too, but that would literally just be a smaller (not square) reverse of the design. I think that would be hilarious.


I'm thinking the best way to make this "modular"ish for as many 5 inch TVs as possible, I will either had mounting brackets or some reference points so people can easily make adapter brackets for their boards and tube mounts. I never mind using adhesives, since they are likely to be stronger than the underlying print, so that would be an easy low-profile solution. With actual mounts, that effectively doubles the screws and screwholes needed for holding the components in place.
 
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vorg

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I fried the first TV's vertical deflector and I fried the Pi Zero W as well. Oh well, more reason to work on V2. I already found and got the component working, although the switch is built into the component port, so for now I just need to stick a plug in to stop the noise. Hopefully I can figure out where the switch traces go to and just add a real switch.

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Sadly I caved for a new Pi Zero W 2, but its a major bummer at today's prices. I have a new ejector gear coming for my Plus, so I am hoping I can get that working while I wait for parts and prints for this.

Still working out the power part too. I need to find somewhere giving off 5 volts, otherwise I need to cut the 12-13.5v down to 5 at the barrel jack.
 
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vorg

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IMG_4662.jpg


Okay, I finally got a decent internal skeleton. My idea is to make it so you can print ore laser cut a base plate that interface with this and your own analog board.

I started printing the front of the case because it's what actually will sandwich the glass in place; it's floppy in this picture. I haven't added the proper mounts and whatnot for SD card readers and the USB c port in the keyboard port, but again, I don't mind gluing stuff until I finalize a design.

This frame is actually printed mostly in "2.5D" and glued together to save time and material. I think a laser cut design would be best but I don't have any kind of wood or acrylic cutter.

I think I might paint this to superficially look like metal.
 

vorg

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2 and a bit more hours to go for the front.


EBF55499-DA5B-4AE4-BFA6-703BCE900B34.jpeg


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Hot off the XYZ press. Somehow it printed way better than v1 in terms of support removal.

1663819045729.png


I can't wait to glue the front CRT frame to the fascia tomorrow, I want to see how tight that screen gap can get.

USB-C female fits in the RJ-9 keyboard slot so that's awesome. I'd love to get a 65% keyboard with a coiled wire to plug into the front.
 
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Trash80toG4

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Loving it! That last CAD profile pic has me wondering if the limiting factor is not the CRT, but the Monitor's board? Don't wanna push too hard on the BackPaq notion, but it seems perfect to wrench your design into perfect or near perfect profile of the Mac Bucket using the extra cubic available at just the right spot for the oversize board with an access panel to ports and controls.

If interested, throw the neck board into that CAD file with overlay on the standard Mac profile as before . . . playtime! :)
 

retr01

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Should the analog board be on the side so that a small fan blows heat out rather than under the CRT with the heat from the flyback and then the CRT? Doesn't that matter? :unsure:

If the case is PLA, then you have limited heat resistance. PETG has better heat resistance.
 

vorg

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Sep 3, 2022
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Should the analog board be on the side so that a small fan blows heat out rather than under the CRT with the heat from the flyback and then the CRT? Doesn't that matter? :unsure:

If the case is PLA, then you have limited heat resistance. PETG has better heat resistance.
I printed something functional ONCE in PLA and it immediately warped. I only print PETG now, except the occasional wood-filled PLA. I think I should be okay, I've got some fans that I will put in this and the case is more open with more vent holes that the original COBY TV case.

I really wanted to have the analog board on the side like the actual Macintosh, but I can't make it work without significantly changing the depth or height of the case, the flyback is always in the way. This set up keeps everything almost where it was in the original TV.

If the PETG does warp, I might try lost-PLA casting with aluminum.
 
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retr01

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If the PETG does warp, I might try lost-PLA casting with aluminum.

As long as the case is PETG, it should not warp. You should be fine. :)

You have the RPi board on the side and then the CRT's analog board on the bottom. I am wondering whether the analog board can be placed on the side and the RPi board on the bottom as an option or does the analog board have to be under the CRT due to the CRT design and connection?