The original had 3x 5V and 1x 12V out. (still haven’t taken the time to figure out where the 12v is for but that will come later)

Thankfully I had a Mean Well switching PS around and Paul mentioned to me that it would easilly do so I set out to replace the old PSU with this one. Cleaned up the connectors as well, where originally the lines were directly soldered to the mainboard.

The new PSU is autoswitching, so the voltage selector is now disonnected.

The emulator supports various modes, two of whcih are interesting for us:

• Mode 0, which means the emulator runs without acceleration, using external roms and memory
• Mode 1, which means the emulator runs without acceleration, using internal roms and memory (basically defined as arrays within the emulator code).

Mode 0 works perfectly, after I set the Teensy to slightly overclock (816 Mhz).

Mode 1 will be a bit more cumbersome, simply because the original software employed bank switching to deal with memory limitations.

This is still doable in the emulator, it needs some custom code though. Also, I’m not quite sure yet which memory limitation they worked around – The EPROMS in total are 40K, well less than the Z80 64K limit.  Here I’m entering the vast learning curve of the Z80 and how it controls hardware.  Below is a picture of the zyklus running on the Teensy. Right now, I’m using this setup but with the USB connected to the computer, so I can see directly what happens. This requires to cut a trace on the Teensy, as it’s powered through the Zyklus (VIN from VUSB).

I’m going to try a few things, meanwhile:

• Write some short diagnostics code that will enable and disable all the LED’s, Buzzer and write something cute on the LCD in Z80 assembly and run that from the Emulator internal ROM.
• Adjust the emulator software so I can define 3 ROM arrays and somehow work out the correct addressing for switching.

Then he surprised us with a completely redesigned modern power supply, suitable as a drop-in replacement. Then dedicated boards for the jacks & midi. And converter boards.
And a new cartridge. And case designs… and .. and…

Meanwhile finding the time to help others with their builds and n00b questions (the n00b’s being mine mostly).

Chapeau Paul, you’re a driving force behind this little hobby project for sure.

Below are a few examples of his hard work:

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, Paul made  a few changes to the KiCad files and ordered a new series of boards to build.
These would be the definite Clone builds.

I’ve test fitted everything in the Original Zyklus enclosure to test:

And it nearly completely fits. The display is taking too much space, using the hex offsets, so I let it rest now on the screws and that fits, but the screws are too short, and the display moved while mounting the board…

Once I got that fixed, I can start testing midi!.

The original devlopers used a different pin order on the IDC flatcable. Not sure if there were standards for them back then, but now there are that was what was used. A new flatcable constructed out of Ardiuno Jumper wires showed this beautiful image:

All buttons and LED’s work as they should. So does the buzzer.  I’m attaching the encoder later, but I have no doubt it will work too.

With that, the power PCB and the panel PCB are done. There is a revision coming of the panel PCB, but that is to clear up a small layout issue and one trace error for which I now use small jumpers.

Onto the mainboard!

One user, PaulMC, has created the KiCad files for the 3 PCB’s and had a first run printed. We’re trying to build these.

I’ve started with the button panel PCB:

Actually, this machine was Pete’s and suffered moisture damage. It was considered dead, but recently it actually did show some signs of life. Given the rarity, all the more reason to refurbish. Besides that,  now I can use this machine as a template while leaving the Vangelis machine in tact. There are some slight differences anyway, both in hardware and software.

So today it arrived and after unpacking it, i noticed with was ratteling a LOT. The case is spotted quite a bit, even some moisture blisters under the paint. Not sure yet how I will tacke this, but that’s for later.

The mainboard and powerboard are sitting on Nylon PCB standoffs, but these were all broken. As a result, everything roamed freely inside, causeing a bit of damage:

So far the list of damage:

• The Voltage selector is wrecked
• The main caps on the powerboard have all come off
• all the standoffs are broken
• one of the EProms has been pushed (but still ok)
• onf of the TTL chips has been pushed (but appears to be conneted ok)
• The 1uf Philips poly cap (yellow block) was pushed and likely is broken
• The two pots on the bottomside of the mainbaord are trashed.

That seems to be the extend of the damage so far. I can see that there’s some corrosion on some of the IC feet, but nothing too bad.

So here were the firs few steps I took with this:

First step was disassemble the machine completely so I could inspect everything in detail.

Next up: getting the EPROMS out and make a dump. This machine has V1.2A, whereas the old Vangelis machine has only V1.2.

Note though, EPROM 0 and 1 are always 1.2. Only EPROM 2 needs the 1.2A.  But I grabbed copies of all the EPROMS anyway.

Next up: Fixing the powerboard.

Replaced the caps with new ones:

And upon close inpsection, there were a few cold solder joints, so I reflowd the entire board.

With that, the powerboard is in optima forma again. In order to move on, I have to do some shopping. Find the poly capacitors and suitable replacement standoffs.

I’m also looking into getting a better desoldering station as that makes life a LOT easier.  To Be Continued……

Yesterday, I started with the powersupply, as that is the most important part and these capacitors have to work the hardest.

This is the powersupply board. It has three 4700uf 16v axial caps:

The procedure is quite simple:

• Desolder the old cap
• Clean the solder pad with wick so that it’s flat, nice and shiny.
• Add flux (I always add extra flux, even when using resin core tin)
• insert the new cap (mind the polarity!!)
• Neatly solder quickly and snipe off the excess.

While looking at the backside, I discovered a ‘cold’ solder joint. This happens on older equipment, where a solder joint just breaks. It can cause interemittend contact or completely no contact.

especially on parts that warm up, these can be a cause for weird behaviour. My Zyklus crashed often on seemingly weird moments. This could have been the cause.

Thankfully, the solution is easy: just reflow:

• Heat up with additional solder until the old joint melts and flows into a new joint.
• After cooling down, it should be a shiny joint again.

Last stap is a check, *before* connecting the PS to the boards:

• Connect the PS to the mains and turn it on
• Measssure the power rails to make sure you get a nice clean 5v output.
• wait 10 minutes with power on and check again.

If you still have a clean 5v output, disconnect the mains and put everything together.

All done!

Shopping list:

3x  4700uF 16v (originals are axials, but with a bit of creatativity, I’ll use normal radials.

3x 220uF 16V (there’s one on the switch/display board as well)

2x 10uF 50v

1x 100uF 6.3V

These things are dirt cheap, so I ordered a ton of each so I have enough for the proto’s as well.

If I have an hour to spare this weekend, I’ll do the recap.

Time to take it apart:

It’s a transforer, transitor, some caps & resistors.  Soon enough I found the culprit:

That is a classic case of a cold solder joint. The tip has broken and the wire which was sodered in here, spun around freely.

A quick heatup with a soldering iron to reflow the solder and it was fixed:

Re-assemble and voila, the display was bright again.

However, since the inverter was severly humming, indicating it was on its last legs and since I’ve seen a few Zyklus machines upgraded with OLED displays, I set out to find a few OLED’s and replace the old LCD anyway.

Coming soon….