Stiga SD 98 ride-on lawnmower repair and mod
(Also includes how to seriously mess something up creating even bigger repair needs) When we bought our property we also purchased a lot of the equipment the previous owner had acquired. An integral part of that is the lawnmower tractor - total size is close to two acres and most of that is covered with grass. It’s a Hurricane HTG 98 SD, which is a model also sold under many other brands. In Sweden the most known one would probably be Stiga SD 98, but in the UK it’s likely an MTD. It has a Briggs & Stratton 17.5HP engine and does a pretty good job, we use it also to transport things around, collect leaves and tidy up the driveway gravel. A week ago it suddenly wouldn’t start. It’s been a bit finicky since we got it, but no matter what I tried it simply didn’t even engage the starter. This points to an electrical issue, right up my alley. Or so you would think. I have degrees in Mechanical Engineering and Software Engineering, but all the electronics stuff I blog about is all self taught. I also looked forward to tearing it down. Like other ride-ons, it has a safety switch where the engine cuts out immediately when it doesn’t detect a driver in the seat. This is all good and well, I really understand why, but when you have a huge lawn there’s just no way you can walk around in preparation for mowing, getting rid of all small rocks, large twigs and the constantly falling pears and apples now during the autumn. I really need to be able to keep it running while quickly moving things out of the way. Since I had a hunch that the reason it didn’t start was another one of the safety switches, I stripped it down and started to search for both where they originated, and where the mower made the decision to whether it was safe to engage the engine or not. Also, to figure out which one it was that was currently not enabling.
English · Htg · Mower · Mtd · Stiga · Tractor · Uncategorized
2099 words
10 minutes
Bitcoin press has gone through the roof in the last few weeks. So has the exchange rate between traditional currencies and bitcoins - a fact that has seen as many different explanations as I’ve seen people wrapping their heads around the Bitcoin concept and writing about it.
Bitcoin · Consumerism · Deflation · Economics · English · Sustainability · Uncategorized
358 words
2 minutes
Tabs - the most valuable screen real estate
As I’m writing this, I have 20 tabs open in my web browser. Of those, the five latest are newly opened and temporary part of things I’m currently researching.
English · Internet · Uncategorized
151 words
1 minute
The Atari Mega ST keyboard - finally exposed
When people talk about the Atari ST range of computers, most mean the common form factor of the times where the computer and keyboard were all one unit. This was true for most of Atari’s machines - but for a few exceptions. The Mega ST, the Mega STE and the TT went for a more “business look”, which apparently meant separation of computer and keyboard. The Mega ST computer has a fantastic “pizza box” style, while the Mega STE and TT share a common … something else.
Atari · English · Retro · Uncategorized
882 words
5 minutes
The delta between an LLM and consciousness
With Facebook’s release of LLaMa , and the subsequent work done with its models by the open community , it’s now possible to run a state of the art “GPT-3 class” LLM on regular consumer hardware. The 13B model, quantized to 4-bit, runs fine on a GPU with ~9GB free VRAM.
AGI · AI · English · LLM · Transhumanism · Uncategorized
468 words
3 minutes
The end of our warm interglacial
“Evidence is increasing, therefore, that a rapid reorganisation of atmospheric and ocean circulation (time-scales of several decades or more) can occur during inter-glacial periods without human interference.”
Climatechange · English · Globalwarming · Uncategorized
401 words
2 minutes
(No, this is not about Musk supporting a racist, homophobic, bigoted authoritarian - others will write endlessly about that today)
AGI · AI · English · Tesla · Uncategorized
511 words
3 minutes
…is this diagram. It’s from [probably the best climate blog](http://wattsupwiththat.wordpress.com/2008/06/15/more-signs-of-the-sun-slowing-down/ "probably the best climate blog") I’ve ever read, and while there’s no question of the author’s own opinions it’s very well researched throughout. [While I’ve claimed](http://blog.troed.se/2007/03/16/its-the-sun-dammit/ "While I’ve claimed") the sun to be the culprit behind not only most other climate shifts in history, but also the latest slight warming (that stopped in 1998!), it’s from reading Watt’s entries I’ve become more than sure.
Climatechange · English · Globalwarming · Uncategorized
182 words
1 minute
The tale of high density Atari mystery
The Atari ST, like other computers at the time, had Dual Density disk drives with 720KB of storage. DD for short. Since High Density (1.44MB) appeared shortly after, Atari used such drives in the more top of the lines models Mega STE and TT. Additionally, us enthusiasts and hardware hackers added HD capability to the regular ST and STE range since it was neat to store twice the amount of data on suitable disks (and it worked pretty well cutting a hole in DD disks tricking the drives into thinking they were HD, even though the magnetic layer is slightly different). All the above is of course very well known. However, recently I’ve managed to dig up some less well known information as well as adding new discoveries about our dear 30 year old hardware. This is a post about that. Atari used several different makes of DD drives in the ST computers, but one of the more common is the Epson SMD-380. For the higher end models with HD support Atari however used one model exclusively, the Epson SMD-340. For after market HD modifications of ST:s one drive in particular became quite popular, the Sony MPF-920. If you search online for kits and instructions, that’s the drive you’ll find the most info on. It’s not only the drive that decides whether to write in Double Density or High Density however. The data needs to be clocked faster through the drive onto the disk, and so it’s not enough just swapping in and out the drives mentioned above to choose between DD and HD support. A neat little trick is that the floppy controller used by Atari, the 1772 (made by WD and VL), outputs a DD capable signal when clocked at 8MHz and HD when clocked at 16. In a regular ST it’s always clocked at 8MHz, and in the Mega STE and TT Atari used carefully tested chips that could do 16MHz (and later elected to produce a variant themselves, known as the AJAX chip, that was designed to run at 16). The way to get HD support in a regular ST is thus to clock the floppy controller at 16MHz when writing/reading an HD disk. I might be misremembering, but I think my own first HD mod needed manual selection through a switch and so I needed to select the right position depending on the disk I used. A much better option is of course to ask the drive if there’s a DD or HD disk inserted, and switch clock speed depending on that. This is what’s well documented for the Sony MPF-920 and is how the many different “HD kits” know what to select. Now here’s where things start to get confusing. In many places you can find documentation to the effect of pin 2 of the floppy interface being a density select signal. An output. While that might be true for some drives, my research says that it’s an input . The Atari Mega STE and TT (the Epson 340 drive) does not get told whether there’s an DD or HD disk in the drive, and yet they still have full support for both formats. This part of the mystery took me to an old discussion thread from 2008 which seems to be the first time someone actually looked into how this was done. There’s a memory mapped register, handled by a PAL chip, that the Atari operating system (TOS) writes to to set the clock frequency of the floppy controller. The logical conclusion is thus that TOS switches frequency when encountering errors and retries. In that sense, the after market ST mods did a much better job. The drive told a piece of circuitry what it should use and the clock frequency was then set correctly. Many many ST top cases have been horribly butchered to make room for the normal eject button of most HD drives instead of Atari’s nice slanted cutout. Of course, I wanted to make my tricked out STE (see other posts) read HD disks as well, since I spend a lot of time archiving lost treasures and sometimes come across HD disks. I did not want to butcher the top casing though. Idea: Use the same HD drive as Atari. The front plate and eject button of the Epson 340 and 380 are interchangeable, and the Epson 340 can still be found used online (and after some digging I found that it was also sold by Hewlett Packard under their brand as D2035-60011). I also bought an HD-kit from exxos that seemed to handle some obscure effects (steprate issues) adding HD to ST:s can cause.
Atari · English · Retro · Uncategorized
1199 words
6 minutes
TL866 firmware updater macOS support
I own a TL866CS IC programmer . Wonderful device - I truly recommend it (and I assume its successor is even better). It’s been known for many years that the company who made them had one hardware revision, and limited the CS revision compared to the A revision purely in firmware. That limitation has of course been hacked for almost as long as the device has existed. Someone going by the name “radioman” detailed many years ago how the bootloader could be reflashed from CS version to A , after which the original software and firmware updates will see the device as the A model in all aspects. To get access to the in-circuit programming abilities, you additionally have to solder a header to the mainboard . radioman’s software is open source, and exists for Linux (QT) and Windows (.NET/QT). People say it works great under parallells or VirtualBox for macOS users. But that’s no fun, is it? I spent the last week changing out libudev for macOS’ native IOKit library in the QT codebase. That’s the only change needed, since libusb has good macOS support. My macOS pull request has now also been accepted and merged into master by radioman. Open source working as intended. And my TL866CS has become a TL866A.
Apple · Code · Development · English · Retro · Uncategorized
213 words
1 minute