Linear voltage regulators such as the 7805 and 7812 are ubiquitous in vintage electronic equipment, and especially in home computers of the late 1970s and early 1980s. They have many advantages are very reliable. Their biggest drawback is their heat dissipation. The variants in metal TO3 packages are only available used or as new old stock. So if you want to replace them with a cooler running variant these brand new drop in replacements based on modern switching regulators might be worth a try. These particular variants have extremely low switching noise, so should be very usable in devices such as the Commodore 1541 floppy drive. So we will repair one of my broken 1541s and also fit it with the modern DR340 voltage regulator!
Let’s Code MS DOS 0x27: AdLib OPL2 Melodic Programming
We continue our quest to learn the secrets of the AdLib sound card and its Yamaha OPL2 FM synthesizer. Last time we did the drum programming, but this time we learn how to code melodic instruments and how to play notes.
Let’s Code MS DOS 0x26: AdLib Drum Machine
Programming the OPL2 FM chip on the original AdLib card can be a bit tedious. Join me in this episode to learn how to program the drums on the AdLib card to create a simple sequencer or drum machine. In the future we will also look at the melodic instruments, but for now we try to create some nice percussion!
Original GameBoy: IPS Mod Horizontal Lines
The IPS display mod for the original GameBoy from a couple of weeks ago already developed a fault. bright horizontal lines run through the display, and it seems a full replacement of the LCD panel is needed. It seems these mods are a bit fragile. Also the display lens is a bit crooked and needs fixing. So off to another round of DMG modding!
The PicoGUS 2.0
Ian Scott, also known as polpo, has upgraded his Raspberry Pico based Gravis Ultrasound clone to version 2.0. It can now be fully factory assembled, and has WaveBlaster support as well as a new design. Let’s test drive the card and see what it can do!
Original GameBoy IPS Mod
A friend gave me two GameBoys, one of which he wanted back after the repair. The other one was dead and I could keep it. So after a quick testing I determined that only the display board was broken due to quite severe battery damage. While maybe salvageable I decided to use a drop in IPS LCD replacement board, as the original DMG screen is pretty abysmal anyway. This mod is relatively easy to install, and requires no soldering!
Let’s Code MS DOS 0x25: A Cozy BASIC Christmas
As is tradition for the Holiday Season on this channel, we will code a little Christmas themed thing in PowerBasic for MS DOS. Grab your copy of PB 3.20 and follow along as we learn how to load a 256 color PCX image and place a nice, cozy fire in there!
Upgrading the PET 3016 to 32KB RAM
A couple of years ago I got a PET 3016 from 1979. The machine comes stock with 16KB of RAM and back then we upgraded it using a RAM/ROM expansion, giving it 32KB of SRAM and BASIC V4 ROMs. However it never ran stable in this configuration. It turns out the SRAM was not playing nice with the system. So in this video we will use new old stock 8116 DRAM chips to upgrade the mainboard to its maximum and hopefully get a stable system.
ZoomFloppy+OpenCBM+8050
The main issue with the Commodore 8050 and 8250 drives is: How do you get data onto them? The units use 100tpi floppy drives that are incompatible to the regular 48tpi and 96tpi disk drives used in the 1541 and in PC DD and HD drives. So there is no chance using those. However there is the ZoomFloppy, which is an implementation of the XUM1541 interface and it comes with an optional IEE488 plug! We can attach the 8050 to that, and use the OpenCBM tools to read and write data to and from the floppies.
Let’s Code MS DOS 0x24: Low Level Keyboard Programming
Getting input from the keyboard can be as easy as calling the getch() function. But for games we need a better solution. For games on MS DOS machines you need quick, unbuffered input. To simply get the state of keypresses we need to talk to the keyboard controller directly. Let’s have a look at how that’s done!