My summer project: A colour Stacy
Posted: Wed Jul 01, 2020 10:59 am
Heh, who would have guessed that @Atarian Computing and I were coincidentally working on similar projects?
I acquired a broken French Stacy early this year and fixed it (bad MMU and bad power switch), but the backlight was in terrible condition, so I decided to explore replacing the display with something modern, and preferably supporting all three graphics modes. People who have tried this before have found that there really isn't a good drop-in replacement for the old screen, but it occurred to me that there's really no reason I can't install a screen that's actually a bit too big, and just ensure that I can scale its input to fit the bezel opening.
I opened up the Stacy and measured the minimum size that would fill the bezel and also the maximum size that would fit between the screw anchors, and plugged that range into an LCD panel search engine and found that the HannStar HSD121PHW1-A03 was a good candidate, and available on AliExpress for around 40€, and I paired it up with this LVDS controller board.
After waiting ages for both parts to arrive from China, I 3D printed some brackets to hold the panel into the Stacy lid, and here's the result (note that the protective plastic is still on the screen here, as I won't remove that until everything is done):
I hooked up the controller board and plugged the monitor output from the Stacy into an OSSC, and voila...
(TOS 2.06 provided by the excellent Cloudy flash TOS board.)
(Still need to work on the OSSC timings to make that look a little better, but I won't do that until the end.)
The LCD controller board has a little daughterboard with buttons to adjust its settings, so I 3D printed a replacement RAM access door, with buttons blatantly pilfered from this great design:
I have replaced the internal PSU (no longer needed since the exotic backlight in the original screen is gone) with a picoPSU, and I've 3D printed a bracket to allow the OSSC board to sit where the old SCSI controller used to live. Today I am in the process of tapping the internal video, which I plan to feed through an internally mounted exxos V4 colour/mono switcher, and also on the roadmap is a Thunder for USB/IDE, and a Storm ST for ALT-RAM. And if I can make it work, possibly a TF536 eventually. I just sent off a little PCB design to Aisler for a CPU relocator that should make it fit, but I admit that I am not anticipating full success on this part.
I don't know how well this stuff will all eventually work together, but progress so far has been pretty promising. Time will tell!
I acquired a broken French Stacy early this year and fixed it (bad MMU and bad power switch), but the backlight was in terrible condition, so I decided to explore replacing the display with something modern, and preferably supporting all three graphics modes. People who have tried this before have found that there really isn't a good drop-in replacement for the old screen, but it occurred to me that there's really no reason I can't install a screen that's actually a bit too big, and just ensure that I can scale its input to fit the bezel opening.
I opened up the Stacy and measured the minimum size that would fill the bezel and also the maximum size that would fit between the screw anchors, and plugged that range into an LCD panel search engine and found that the HannStar HSD121PHW1-A03 was a good candidate, and available on AliExpress for around 40€, and I paired it up with this LVDS controller board.
After waiting ages for both parts to arrive from China, I 3D printed some brackets to hold the panel into the Stacy lid, and here's the result (note that the protective plastic is still on the screen here, as I won't remove that until everything is done):
I hooked up the controller board and plugged the monitor output from the Stacy into an OSSC, and voila...
(TOS 2.06 provided by the excellent Cloudy flash TOS board.)
(Still need to work on the OSSC timings to make that look a little better, but I won't do that until the end.)
The LCD controller board has a little daughterboard with buttons to adjust its settings, so I 3D printed a replacement RAM access door, with buttons blatantly pilfered from this great design:
I have replaced the internal PSU (no longer needed since the exotic backlight in the original screen is gone) with a picoPSU, and I've 3D printed a bracket to allow the OSSC board to sit where the old SCSI controller used to live. Today I am in the process of tapping the internal video, which I plan to feed through an internally mounted exxos V4 colour/mono switcher, and also on the roadmap is a Thunder for USB/IDE, and a Storm ST for ALT-RAM. And if I can make it work, possibly a TF536 eventually. I just sent off a little PCB design to Aisler for a CPU relocator that should make it fit, but I admit that I am not anticipating full success on this part.
I don't know how well this stuff will all eventually work together, but progress so far has been pretty promising. Time will tell!