A couple of games back in the 1990s utilised the VGA split screen functionality to enable things that were otherwise only possible on more capable machines, like the Amiga. The VGA split screen allowed games such as Jazz Jackrabbit or Pinball Fantasies to display a static status bar at the bottom of the screen, while the rest of the screen was smoothly scrolling in two or more directions. In this video I will show how this is possible, and which VGA registers to program with the appropriate values.
Commodore SFD 1001 Repair
Another dead floppy drive has landed on my desk. I was told that “the motor isn’t working”. That can have different causes, but let’s find out what the actual problem is. I never worked on one of these drives before, but they are related to the CBM 8050, a drive that I like very much.
Spin Me Round: Commodore 1541 Repair
We have another dead 1541 floppy disk drive on the bench today. It is an infinitely spinning drive, so it means that somehow the drive is not booting. But what might be the cause…?
Double Trouble: C64 and 1541 Repair
I have two dead Commodore devices here, that a user asked me to repair. A 1541 floppy disk drive and a bread bin C64. The drive’s motor spins indefinitely and the LEDs don’t come on. The C64 has a black screen. So let’s get cracking, and repair both! With the C64 I made a couple of wrong turns, but in the end all turned out well! The 1541 had some other idea in store for me, and turned out to be a bit on the spiritual side…
The Horror: GameBoy Backlight Mod
The original GameBoy (DMG) had not the best LCD display that one could wish for. Most importantly it was a reflective only display, which required substantial amounts of external light to be visible. A friend sent me their DMG with the request to install an LED backlight mod. I thought: how hard can it be? Well, you be the judge of it…
Let’s Code MS DOS 0x31: ANSI C Data Types
The C programming language has only few builtin data types. But for a beginner those can be a bit confusing. So we will have a look at what data types are offered, and what kind of new datatypes you can build with C.
NEW Low Ripple 7805/7812 Drop In Regulator
Not even two years ago I published a video about the DR323 / DR78xx switching regulator by Mr Floppy, which is a replacement for the linear LM323 and 78xx series of positive voltage regulators. Their main advantage was their extremely low ripple, compared to other solutions such as the ezSBC. Now Mr Floppy has developed v0.2 of the regulator, which has some small improvements, and removed the surface mount coaxial port for probing. Instead he developed the Checker Board, which can be used to do accurate probing of TO3 voltage regulators.
Let’s Code MS DOS 0x30: VGA 3D Textmode
The EGA and VGA card can do a lot of magic tricks in textmode. This time we will investigate how you can draw a rotating 3D cube overlayed on normal text by utilising the EGA/VGA feature of a second character set.
Let’s Code MS DOS 0x2F: Mandelbrot Fractal
Everybody knows the Mandelbrot set. It is one of the most famous fractals. And it is easy to code! At least if you don’t care about speed… So let’s try to code it for ancient MS DOS PCs with VGA cards! And there will be color cycling!
Pico DRAM Tester
Eric Schlaepfer aka TubeTime has released an open source tester for vintage DRAM ICs. It is based on the fabulous Raspberry Pi Pico 2 microcontroller. It supports even older chips that use -5V and +12V. I ordered PCBs and the components for building the tester, so let’s warm up the soldering iron and build something!