Project STacy (STaceX, TOS 2.06 & others)

[Atarian Computing]

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[exxos]

[keli]

Do you happen to have a part number/digikey link/etc. for the mega bus connector on that adapter?

[Atarian Computing]

Do you happen to have a part number/digikey link/etc. for the mega bus connector on that adapter?

Yes, it’s this one: https://www.digikey.fi/product-detail/e ... ND/1036427

[Atarian Computing]

Stuff I did on Saturday.

Waiting for EPROMs.

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I managed to get my “development” unit up and running. Had to hack in a Mega ST keyboard and external trackball. I also needed to replace 5 transistors on the DC/DC board. 2xD1060 and 3xC3691.

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My messy but working sipps. Need to be almost 90 degree angle, otherwise they won’t fit.

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[Atarian Computing]

Just waiting for the MACH210 chips to be programmed and shipped. Fingers crossed that it works!

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[Atarian Computing]

Hi, just a brief message from my website:

I apologize for no updates in the recent months. I'm still fully committed to running this website. Due to major changes in my full-time employment, all my free time has been diverted to learning the ropes and teaching myself new skills. The changes are very positive and my employer has remained the same. I now work in IT for a major insurance company where I can fully utilize my skillset.

With the holiday season coming up as well, I expect that it will be a couple of months before I can start working on my Atari projects. Merry Christmas and a Happy New Year to all.

Josh.

[Atarian Computing]

Alright, I'm slowly starting to get some free time. A generous Atarian has promised to lend me their non-working Magnum ST with a known working SIMM. I'm sure that I can troubleshoot with that. From my website:

So, it's almost the end of April. Crazy. Things have been great at my new job. I've learned a lot. I've already programmed several tools with GUIs with my new best friend; PowerShell. It's amazing.

I feel like I'm at a place where I can focus a bit of my time to running Atarian Computing again although, I will be busy renovating my place of operations (roof and exterior). You should be hearing more of me in the coming weeks.

[Atarian Computing]

Well, regarding the Magnum ST, I haven't really learned enough to make conclusions. I did get a loaner and was able to confirm that my SIMMs were ok.

However, the loaner's MACH210 wouldn't even boot on my unit and vice versa. With the same ROMs too and same machine. So don't know what to think of that. The fact that my Magnum ST boots (It has TOS 2.06) says that my MACH210s at least work in decoding and therefore one could expect it to work in the other department which is alt-ram. Why then would that Mach210 not even boot on a known working Magnum ST? And why won't my Magnum ST boot with a MACH210 from a known working Magnum ST? So I decided that I'll shelve this project for now and pick it up some other time. I did some repairs and improvements that were necessary on the loaner unit and sent it back.

Since getting a blank PAK68/3 PCB, I've toyed with the idea of a SuperSTacy like DarkLord's. But I'd really hate to work with the original DC to DC board due to its size and performance (or lack thereof). Despite the various opinions of Pico PSU's and their place in Atari machines, I think everyone would agree that it would be justified due to space restrictions.

Problem is the LCD bias supply of -20V. I know that one could use a MAX629 (https://datasheets.maximintegrated.com/en/ds/MAX629.pdf) in a circuit to generate that voltage but I'm afraid of high frequency noise that would affect everything and show up everywhere and also the resulting spikes from the switching.

How would one go ahead and create a suitable -20V for the Stacy LCD?

[Atarian Computing]

Project is far from dead. I've been thinking and planning. I haven't been entirely happy with the current STaceX as it doesn't allow for serious upgrades due to space restrictions and the bus extension. That's why I haven't bothered with getting the Magnum ST to work.

Major pitfall is the DC-DC converter. It's huge, and almost unnecessary. Many don't realize that you can actually toss the DC-DC away and power the STacy by feeding power to the floppy power connector. However, this would require the use of an external monitor as the LCD is deprived of the -20V bias supply and the EL-backlight of 85V AC @ 590Hz. So all that bulk just for the LCD? There has got to be a better way.

Darklord and AlanH are pioneers with experimenting on the STacy. AlanH showed us the trick of powering the STacy with just the floppy power cable. Darklord went as far as anyone could with trying to adapt another, much more modern DC-DC converter we love or hate, the PicoPSU. One of the two obstacles was overcome with Darklord finding a separate inverter for the EL-backlight. That remains the best alternative so far. The -20V source sadly has been elusive.

I already mentioned the MAX629 in my previous post just above. I'm no engineer. I made my first PCB exactly a year ago. But I did find Maxim's datasheet for an evaluation board for said IC. Layout and all and for -20V. See here: https://datasheets.maximintegrated.com/ ... 9EVKIT.pdf. Seems trivial enough to do.

So would open all kinds of possibilities. Here's what I've been thinking of:

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It's crude. I might have overlooked something, but physically it should fit.

So, lot's of space now. So here's where I'm gonna need help. Considering how far I've come in a year, I'm sure I could cook up something really cool in a few years time. Right now it's just basic stuff.

If there could be some collab to get alt-ram, flash-TOS, IDE, and a booster in there, that would be sweet. I can do all those individually but to get them working together on a single board...yeah...not there yet.

Otherwise it's plan B:

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