Let’s Code MS DOS 0x1D: Melting the VGA Screen

One of the effects that is easy to do on machines like the C64 or Amiga is the „melting screen“. In theory you can do such things just by copying lots of pixels in video memory. However the VGA is rather slow for doing that. So what we will do instead is cleverly manipulating the CRTC registers of the VGA to achieve a similar effect. This lets us move big portions of the screen without actually copying any bytes.

Atari 2600 Jr: AV Composite Mod (No RF Modulator Box)

About a year ago I acquired a very cheap Atari 2600 Jr. It had only RF output, so I can’t use it on my CM8833-II monitor. A composite mod was required. I decided this time around to get the deluxe mod from The Future Was 8bit and see if it’s worth the extra expense. For extra points, after opening up the Atari, I noticed I have one of the more rare variants without the big metal RF modulator box, but instead have a bunch of discrete components on the board. So where to get the instructions? Luckily archive.org never forgets!

Repairing a Commodore 1541 Floppy Drive

Some time ago I acquired a very affordable Commodore 1541 drive. This is the original one that came with the earliest C64s, and it is an absolute unit of a floppy drive. It contains a pretty hefty transformer and lots of metal parts. This device came es untested/defective, and sure enough: both LEDs stayed on after power up. So I took to it to try and get it repaired.

Let’s Code MS DOS 0x1C: The Dweezil Fractal Zoomer

Back in 1993 two Finnish demoscene coders by the names of Dweezil and Tsunami came up (probably independently?) with a graphical effect that became known as the infinite fractal zoomer. Sometims it’s also called the Dweezil zoomer. The Linux xscreensaver knows it by the name of Kumppa. It is a clever and simple algorithm which allows even pretty slow machines to do an impressive infinite rotating zoom. Today I will talk you through the algorithm and we will do the actual implementation in Turbo C, using VGA 320×200 and 256 colors.

Learning SMD Soldering – With LEDs!

I love those little SMD soldering kits for practicing manual surface mount component soldering. They are only 2-3 EUR each and you can practice your skills before you try and repair you precious vintage hardware or broken modern console or laptop. This time I got a nice kit from a Chinese seller which includes (Chinese) instructions and actually can be tested without a testing harness, simply by looking at the LEDs. So let’s do some soldering!

Upgrading the Commodore PET for “Attack of the Petscii Robots”

For Christmas I got a surprise: a 1979 Commodore PET 3016. This is the predecessor of the VIC20 and C64 and comes stock with 16 KiB of RAM. Last year Dave Murray, better known as the 8bitguy, announced a brand new game for the PET, called: Attack of the Petscii Robots. So this was a lucky coincidence! I ordered a boxed copy of the game and also ordered a PCB and parts to build a 32 KiB RAM expansion for the PET. I showed the soldering and assembly of the expansion in a previous livestream. However we still need to install and test drive both the PET and the game! So that’s what we’ll do today.

MegaDrive Megademo: Overdrive 2 by Titan

Not only the Amiga has an active demoscene! The SEGA MegaDrive (also known as the SEGA Genesis in other countries) has seen some magnificient productions over the last years. Let’s have a look at Titan’s Overdrive 2 Megademo. It is amazing what the coders were able to get out of this late 80s, 64KB tiny machine.

My 2nd Most Favorite Amiga Demo

The other day I published a video about The Electronic Knight’s new demo called “Hologon”. It seemed that a lot of people liked that video. So I want to show another of my most favorite Amiga OCS demos. This time it’s EON by Black Lotus. There are not terrible many new effects, but everything is highly polished, making this demo a true piece of art.

Playing Game Music without a PC: The Roland SB55

Roland produced a number of SoundCanvas and related products. The SoundCanvas 55 came with an optional device called the SoundBrush 55. This was a floppy based MIDI recorder and player. Musicians could use it to either play back MIDI files or alternatively to record their performances. We will of course use the device to play back video game music without the need of a PC! I will have a look inside this device, which is well over 25 years old and also will hook it up to my SC55 and the MT32.

Pimping the C64

A good friend of the channel by the name of matze79 supplied me with a rather cheap C64G. As I didn’t own a C64 at the moment, this was an excellent opportunity. The poort little C64 came with two missing keys, which were fixed by 3D printed replacements. While this looks interesting and is impressive in its own right, I wanted a more long lasting fix. The C64 was also missing its SID chip and came with a nice little SwinSID. But again, we have some better replacement on hand! So let’s open up the machine, fix those things and enjoy the fantastic world of programs the C64 has to offer!