We already had a C64G on the channel, which was working fine, but was missing some keys and came „only“ with a SwinSID. This time we get a regular brown breadbin C64 with a fault: It’s showing flickery colors. This might be due to two things: Either the 1K color SRAM or the PLA might be broken. One way to find out: open up and replace some chips!
The 74 series of ICs is one of the longest running IC series. They encompass all basic logic functions and more. It is (almost) possible to build basically any digital circuit from chips of this series, without needing to use a micro controller. However it quickly becomes expensive as the transistor density of those chips is not very high. But they are a great way to learn about transistor-transistor-logic, or TTL. Today we’ll build the „TTL Graveyard Clock“, named as such because it… looks a bit like a graveyard, and this is also where 74 series chips go to die…? Kidding aside, this clock is an impressive design by Sergey Kiselev and a great way to learn soldering as well as to learn how 74 series ICs work. Plus in the end you get a fully functioning 24 hour clock with seconds!
I got an old Galep-III universal EPROM programmer from a friend. He couldn’t get the device to work under Windows 10, since it is quite old and uses the parallel port. This device is perfect for my 486! And since I just finished assembling an XT CF Lite card, I needed something to write its EEPROM with.
The device looks a bit aged, due to dirt and severe yellowing, so we will clean it and retrobrite it, to make it look like new. This is only my second attempt (after an experiment with my serial mouse), so let’s hope for the best!
The holy grail of PC soundcards include a few special devices. But one of them is surely the Gravis Ultrasound. It allowed mixing of 32 independent channels with (near) CD quality. This could be used for sound effects or music, and was particularly popular in the demo scene. But also game classics such as Jazz Jackrabbit, One Must Fall, Epic Pinball and Pinball Fantasies used the card to great effect. However today an original Ultrasound costs anywhere between 200-400 EUR, which is a bit too expensive in my opinion. So we try out a cheap homebrew clone! Meet the GUSar lite!
There are two kinds of soldering PCBs: through hole and SMD. Through hole uses components with leads, which are threaded through holes (hence the name) in the PCB and then fixed to the PCB with solder. SMD uses Surface Mounted components. That is, very miniaturized components that are soldered onto the surface of the PCB, without using leads.
Due to the small size of the components it is at first much harder to solder than for classic through hole parts. To save you from the misfortunes of failed projects, there are practice kits available. We will assemble one such example today and I will try to teach you the basics of SMD soldering as well as some more advanced tricks.
The Innovation SSI-2001 was a very early PC sound card which appeared roughly during the release period of the Adlib. It was supported only by a handful of games and disappeared very quickly from the market. What makes it notable is the fact that it used the MOS6581 also known as the SID as its core. This chip was better known as the chip that drove the Commodore 64’s sound. Hence this card is particularly interesting. Early this year I hand soldered a replica of this card, known as the Renovation SSI-2001. Today we want to test drive a couple of games and compare different SID implementations: An original MOS6581, a SwinSID nano and the ArmSID. Can the much cheaper emulated SIDs hold a candle to the expensive and ever rarer original in this setting? We also take a short stab at getting the SID to produce a tone using MS DOS QBasic!
I acquired a Commodore 1084S CRT monitor. This is a pretty good, classic monitor for the Amiga and other systems. The device is already 28 years old, so it has some ageing problems. Namely the power switch will not stay locked in. I got myself a replacement part and will try to solder it in!
Today I got a package from fellow retro nerd Matze79, aka Retroianer. He sent me two PCB kits for parallel port sound cards: The TNDLPT and the LPTsnd. The former is Tandy compatible sound device by Serdaco, who sells quite a bit of retro kits, and the latter is a DAC for the printer port by Matze79 himself. The two boards let you add either 3 voice synthesized music or 8 bit PCM playback capability to retro DOS machines. A lot of very old games don’t support SoundBlaster or Adlib cards so these are options for getting better sound with your gaming experience. Also many old laptops of the 386 and 486 era don’t come with builtin sound cards, which is why these devices here are useful as well.