Category: Blog

This took a lot of tinkering and quite a bit of frustration too, but I’ve finally got Direct working with new EPROMS that I wrote myself. Going through a lot of issues with various assemblers (being on a Mac) and not knowing all the details obviously of coding ASM for Motorola which is still quite […]

Where you just can’t stop tinkering. The machine started somewhat and I did a quick check to see that the HALT line and RESET line were both ok, indicating that the CPU is in working mode. I was googleing on various 68000 related diagnostics issues when a single post caught my eye that talked about […]

A very long day of building. Today the new panel board came in, so I assembled that and the fit was perfect. I also reinstalled the powersupply in the case, along with a slight modification to make it somewhat better accesible, using some connector blocks. Also some small parts were delivered so I could finish […]

I repainted most of the case. I didn’t want to paint over the existing “direct” labels and other text, but everything else is painted. It came out ok enough, certainly a lot better than it was. To get it really good though, the whole case should have been stripped & sandblasted. Some rusty area’s really […]

While other parts of the renovation are calmly cooking, I thought I’d spend some time on actual coding. I dumped the original EPROM’s, analyzed its contents (even tried to disassemble), but they are hopelessly corrupt. No real problem, code is available so I can build new ones. I had two avenue’s to choose from. In […]

That was a really quick turnaround! Here’s the new switchboard.   I build it up with the switches, diodes, resistors and new extra long header pins.     A test fit to the front panel showed that it was nearly perfect. Only the lower row could use a nudge (less than 1 mm) up and […]

I have to replace a few components on the mainboard as well as a voltage regulator on the powersupply and some other bits & pieces. So first up is checking in detail what I need. Some of the coding on diodes etc has been worn off, so I’m using a desktop microscope to see if […]

Went to a local specialized paintsshop yesterday to have the colors scanned and mixed in machine grade paints. There will always be a color difference because the current paint is old and was subject to years of wear and stuff. But it will be better than rust. 🙂 Also included a high end primer, the […]

Thanks to Paul, who did the Zyklus boards as well, a new panel board is taking shape. I’ve been toying a bit with Kicad, but Paul is such a master in it, it takes me a day to do what he can do in a minute. With a pinch of luck, in about a week […]

Upon close inspection, the panel board suffered enough moisture damage to decide to scrap the board and create a new one. It’s not a complex board at all, thankfully. I started by removing all the switches so all the traces could be reviewed. During this process it became obvious that most switches have snuffed it […]

And I got to inspect it up close to see where we’re at. First I took a ton of close up pictures I can use for referencing wiring etc. Next up was to remove the mainboard. This yielded a surprise on the backside. Some kind of rubbery substance was splashed over the backside. I noticed […]

Here starts an important and cool restoration project. A lot has been said and written in the past about Vangelis custom “Direct” machine – as a result, this particular device has retained a certain ‘mystique’ on what exactly it did. We’ll probably never fully know for sure as some things like the most recent software […]

There is a little update, now that I’ve receieved one of the Most Amazing frontpanels created by Paul – and holy cow does it look good! He made one for himself compleet with wooden sides etc, and oh my…. I’m working on the Teensy version as well and mostly actually on the software, which is […]

So now that we have succesfully cloned the Zyklus with that learned a great deal on how it all works from a hardware perspective, it’s time to get deep with the code and try a new hardware platform. Obviously the Z80 is limited, which is why the code included some very handy bank switching to […]

The original Zyklus code was written in Z80 Assmebly, using a Macro assembler from 1985. Thanks to the current popularity of retro computing and the vast resources of the internet, I managed to obtain a copy of the assembler (though not the linker, although I’m fairly certain I have one from an earlier release that […]

After having new MCLZ8 boards created, this time with the components pre-populated (and thanks Paul for guiding me through the ordering process on that), I now have a working MCLZ8 emulator running. The emulator supports various modes, two of whcih are interesting for us: Mode 0, which means the emulator runs without acceleration, using external […]

I want to introduce our user PaulMC a bit. This gentleman has been responsible for a lot of the succeses we’ve had. He took the schematics and created new PCB layouts and basically nailed them in the first try. Then he surprised us with a completely redesigned modern power supply, suitable as a drop-in replacement. […]

This gentleman (https://microcorelabs.wordpress.com/) has created a Z80 Emulator, based on a Teensy 4.1 module. It is supposed to be a drop-in replacement for the cpu, with which we can use its features to easilly develop new features for the Zyklus. Using this emulator would negate the need to burn new EPROMS, as we can simply […]

I’m trying to think of ways to deal with the software. My thoughts for now are to create a hardware abstraction layer with API’s that the software can interact with. By decoupling the logic from the hardware, it should theoretically be easier to develop new functions. And to simulate these. Not sure yet how I’m […]

It’s been a while – I’ve been a bit busy. But here we go. A new Zyklus is born. Actually, quite a while ago, User PaulMc and myself managed to finsih building the first version of the mainboard. While there were one or two little bugs, it ended up working quite nicely! So with that, […]

It’s been a while, but there was a lot of progress. All the boards have now been built. The powersupply board works as should. There was an issue with the voltage regulator being not strong enough (1.5A), so it’s been replaced with a 2A variant and now it works nicely. It gets hot though. The […]

So after spending some time debugging and not getting why the new button panel board didn’t work, as it measssured exactly how it should following the schematics, and after basically replacing every TTL chip (I did find some dodgy ones), it was time to start comparing it to the original and soon enough the issue […]