Re: My summer project: A colour Stacy
Posted: Wed Jul 01, 2020 12:08 pm
We welcome retro users & hardware gurus alike! Come and join the party :)
The Cloudy is a really nice upgrade. But of course as you well know, the space available above the 68000 in a stock Stacy with a stock internal PSU is basically nil after you socket the 68k. Early on in this Stacy project (before deciding to chuck the factory display), I designed a CPU relocator PCB for the Stacy that plugs into the 68k socket and provides a 68k socket over where the SCSI controller used to live. It actually worked fine with just the 68k plugged in, but I was never able to get it run stable with the Thunder and Cloudy boards installed, in part or perhaps entirely because that internal PSU generates a lot of EMI and my relocator board was necessarily running the entire CPU bus across the computer, right below the PSU. Fortunately, that whole operation became moot once I decided to replace the screen.
I suppose Thorsten confused the STacy with the ST Book. (The latter uses a modified TOS 2.0x.)
Just out of curiosity: Could you post a photo of the Cloudy fitted in the STacy? And, if you upgrade with Lightning ST (for IDE/USB) and Storm ST (for Alt-RAM), as you mentioned, I'd also love to see photos of that.
I sure will once it's back in there. Right now it's all pulled back out while I work on the video stuff.
My man. Thank you. I was just pulling the schematicsderkom wrote: ↑Thu Jul 02, 2020 5:13 pmGot the internal video connection built, and it actually works.
@Atarian Computing, in case you want to build own VGA tap, here's the places I tapped:
R - R54 toward rear (these resistors are right by the monitor port)
G - R56 toward rear
B - R59 toward rear
Mono - R62 toward rear
H - D15 toward rear (these diodes are by the ACSI port)
V - D5 toward front
GND - D15 toward front and R55 toward rear (my cable is shielded, and I grounded both ends of the Y split, also grounded the other end on the disk cage leg)
MONO ON - 68901 pin 29
+12V - R58 toward rear
Of course if you're shooting for mono only, this job is somewhat easier.
Note that the Stacy monitor port has a physical switch in it that forces MONO ON to GND if there is no monitor plugged in. For the moment I've just stuck in the DIN13 plug I removed from the VGA converter. I haven't decided yet how to deal with this long term, but plugging in 13 little antennas is likely not the best solution. I'll probably either build a DIN13 plug with only the shield (this is what pushes the switch) or 3D print a little wedge device to mount internally and hold the switch.
Also, at least on my Stacy (and I presume all of them), the 12V wire on the floppy drive connectors is not hooked up to anything, so if using the trick of feeding power for the Stacy into the floppy connector, a separate connection into the +12V net is required for the VGA converter to function.
As long as your (current) goal is only mono, you don't need to worry about it, since you'll want the mono detect grounded all the time anyway. But if you do later go for colour, you'll need to deal with it.
That was my initial plan, but then I decided to use the floppy connector simply because it was closer to where I'm mounting the picoPSU. I didn't discover the lack of 12V until after I'd already hooked that all up, and just decided to tap the high side of R58 right next to the shifter. If I had it all to do over, I would feed into the power connector like you did. Live and learn.I feed the voltages to the right DC-DC connector to get the -12v as well.
Today I realised that that the Lightning IDE/USB interface won't fit directly onto the CPU bus unless it is very nearly the bottom of the stack. Otherwise it runs into the keyboard. I'd forgotten that my CPU relocator folly not only moved the socket over to the right hand side, but also toward the back a bit, allowing the Lightning to fit into the space between the disk cage and the keyboard. But the problem with making the Lightning the bottom of the stack is that it runs into the old PSU header. So, thinking about what @Atarian Computing said about -12V (I'd forgotten that's necessary for serial!), I decided to use the old PSU header for power, and pull off the old header and install some 90° headers...