Macintosh PortraitDisplay Recap and Geometry Adjustments

[naruse]

Not sure where to place this (mods let me know if its fine here, else I can move it )


The Apple Portrait Display, released in 1989, was a groundbreaking monitor that broke away from the conventional 4:3 aspect ratio of its time. Designed with productivity in mind, it featured a tall 15-inch grayscale screen with a unique 640x870 resolution with a refresh rate of 75Hz!, ideal for displaying entire pages of text or layouts without scrolling. This made it a favorite for desktop publishing, word processing, and other professional tasks requiring precise attention to detail.

Compatible primarily with Macintosh computers, the Portrait Display utilized Apple's innovative QuickDraw graphics technology to render crisp, detailed images and text. It connected via the Macintosh II series’ proprietary video cards and became a hallmark of Apple's commitment to design and functionality tailored to specific user needs.

The Apple Portrait Display remains a fascinating piece of computing history, exemplifying Apple's early efforts to cater to creative professionals. Its striking form factor and focus on vertical workspace set a precedent for modern portrait-oriented screens and remain an iconic reminder of a time when Apple pushed the boundaries of hardware design. More info can be found here https://lowendmac.com/1989/macintosh-portrait-display/

I created a small video on what it contains inside, how to recap it (it has LOTS of caps) and how to set the geometry adjustments. hope you enjoy it!

Important links:
* Display Service Utility
https://macintoshgarden.org/apps/disp...

* Portrait display capacitor list (NOTE: use it as a reference but be weary that you need 105c rated caps instead of 85c ones on the neck and sweep boards)
https://tinkerdifferent.com/threads/m...

 

[JDW]

Will there be a part II video where you show us the same desktop windows again to see if the problem you showed at the beginning of your video vanishes with that different video card? Before you even mentioned having discussed it on Discord, I too thought it might be the video card — specifically the VRAM on the card. I had a Micron Xceed with unusual artifacts and after a VRAM chip was replaced, the problem went away. I didn't repair that card myself but instead mailed it off to Belle in Germany who did a fine job repairing it. Just curious how everything looks now after your recap and different video card.

 

[naruse]

hey @JDW !

Thanks for checking out the video! . That's a great point, I didnt show how the monitor looks with a different video card .

But the plot gets better! -- with the same video card, I realized that I had the monitor set to black & white, that video card lets me set the video to B&W, 4 Colors, 16 and 256 iirc.

You will not believe it but I was checking it with the scope (the DHO804 that you recommended me!) and I noticed that one bank of the video card is not active when the colors are set to B&W (there is no clock signal on the vram ICs. Once I set the video card to at least 4 colors; the 2nd bank gets a clock signal and the portrait display issue gets fixed! -- it seems that the portrait display just doesnt like black and white colors only.

I think I have enough material to get a 2nd video going; thanks for the suggestion

 

[JDW]

It was the same when my Micron Xceed card had VRAM related issues. Switching between color and grayscale or switching between number of colors would sometimes resolve the problem. But ultimately, replacing the defective VRAM chip was the solution.

Congrats on the purchase of that excellent 12-bit scope! Incredibly low-cost, yet with resolution and features rivaling scopes that cost over $2,000.

 

[naruse]

Alright, it took me a bit to do this but here is the 2nd part!

I tested this out with another video card and with B&W works well. I then went ahead and changed the monitor + the original (defective) card and with B&W works "well" -- in regards that you still see the background as blue .

Still, I am quite relieved that the video card will work with a portrait display with 4+ colors (which will be normally the case). I hardly see myself toying around with the portrait display on B&W .

The portrait display image crispness is quite a pleasure to see in these old machines

It seems that video card I used originally could be a prototype video card https://68kmla.org/bb/index.php?thr...-630-0400-preproduction-trident-v1-0a1.47523/ so it could very well be a reason on why it doesnt like to play with the portrait display

 

[JDW]

I just watched your video. Very interesting. I’ll tag @David Cook since you linked to his 68kMLA post.

Some video cards like Radius required their driver to be loaded as an extension in order for the card to work as intended. Other cards didn’t have such INITs.

So I am wondering if there is an INIT required for your “prototype” card to work properly?