« Cray-1 - The home sup… | Home |

VIC-20 The friendly computer

How I restored a piece of my childhood

Scritto da Silicon_Simon.
Domenica 15 Agosto 2021, 5:26 pm. Tag usati: , ,


2021-08/vespacommodore.jpgIt’s been a long while since my last post on this blog. This boring era made of real time social things and dynamic digital networks full of contacts and followers (my optimal number of social interactions is far below the Dunbar’s number!) is eroding the time once devoted to write something more well-finished.

Anyway, a new post in the end, 5 years from my last one here. I will write again about retro-nerd-things and restorations I usually make during holidays, when I am far from everyday duties.

This year, also due to the home relocation we started months ago and which is still unfinished, I dedicated my time to fix and restore my first computer, yes the first one I have ever, ever had in my hands. All of my so long forgotten knowledge about it is deeply buried in the mist of my childhood memories, back to early 1984 if I am correct.

In that year Piaggio (my father then worked for them in a big bike dealership in Bologna) launched an ad campaign focused on a Commodore VIC-20 given away as a gift for customers purchasing a Vespa PX125. I can clearly remember those coloured boxes lying on the shelves, in the customer care area of BeMotor (the dealership’s name, today oriented in selling cars only).

Well, I had to insist a lot, really a lot, but finally I got my own box from that shelf, and yet without having to buy a Vespa to get it. The Commodore VIC-20 was an 8-bit home computer sold by Commodore Business Machines. The VIC-20 was announced in 1980, roughly three years after Commodore's first personal computer, the PET (Personal Electronic Transactor, much more oriented to the business market). The VIC-20 was the first micro-computer to sell one million units. Bruce M. Arnold reported it as "one of the first anti-spectatorial, non-esoteric computers by design...no longer relegated to hobbyist/enthusiasts or those with money, the computer Commodore developed was the computer of the future."

1984 was a tough year for me: my mum had severe surgery, I lost my granpa in November and I had to spend plenty of time alone, since my relatives had to solve those more important problems than looking after me. But I was not actually lonely: I could switch the crt TV set in the dining room on and, tuning it on the channel 36, the magic could happen! Now I have lost most of the wonder, since I know how the analogic frequency for the video signal works (591,25 Mhz by the way), but boy, back in 1984 it was awesome! A computer in my own TV! A pretty decent monitor was then a far and too expensive desire. After some tuning, anyway, the massive power adapter was the last thing to arrange aside of the breadbin computer before starting to type something on the brown keyboard.

Yash Terakura, who developed the VIC-1001 (the first VIC-20 released in Japan), later said: "With the computer-in-a-keyboard concept, there was no room for an internal power supply. This meant engineers had to design an external power supply. The power brick made the Vixen look less refined, which is why marketers rarely showed the computer with the cables and power supply in the same photograph. Heat was a major concern in the Vixen design.” Vixen was the codename invented by Robert Russell who was unenthusiastic about the word VIC, which "sounded like a plumber". Russell was one of the talented programmers, together with Bob Yannes, who also worked on the BASIC ROM of the VIC-20 prototype.

In his wonderful book “Commodore, a company on the edge”, Brian Bagnall mentions Yannes’ project, which came together in his home. “There’s a story going around about how I built the VIC-20 prototype in my garage”, Yannes reports in the book. “It wasn’t my garage, it was my bedroom. I didn’t have a garage.

Bagnall quotes Yannes again when he affirms that “the final design of the VIC-20 was nothing like his prototype. If you look at the VIC-20, it is a PET”.

At the very beginning my Commodore experience was the out-of-the-box one. No ideas on how to use it, except for the handbook, probably one the best written computer manuals in history. But I could feel there was potential behind those buttons, and there was also history. In 1969, a large industrial manufacturing company called Allen-Bradley wanted to enter the new semiconductor business. It financed the creation of MOS Technology. For the first five years, MOS Technology supplied calculator chips and other semiconductor parts to the electronics industry. Then, on August 19, 1974, Chuck Peddle and his team of former Motorola employees (he was one of the Motorola 6800 fathers) began working on a revolution in microprocessor technology, later named 6502. The MOS 6502 was an innovative chip, which offered performance superior to that of the Motorola 6800 at a cost of $25 only (the 6800 was correspondingly expensive with its price of $200). Due to this, the 6502 was very successful and it was used in many 8-bit computers of the time such as the Apple I, the Apple II, the Nintendo Entertainment System (NES), some Acorn Computers, the 8-bit Atari computers, some Oric BBC Micro-computers and, of course, the Commodore VIC-20.

Again, from the Bagnall’s book: “There should be no question in anyone’s mind that the primary architect behind the VIC-20 was Bill Seiler,” says Peddle. “We didn’t have to go back and invent all kinds of new things except for the I/O stuff. We were just basically putting it all together to make it work.” VIC chip in it,” he says. “It has the same I/O structure and the same processor, and the kernel code that was running in there was the PET operating system kernel.”

Peedle, a genius, often animatedly argued with Jack Tramiel, the Commodore founder and CEO, that the VIC-20 project was time wasting and the company should have been focused on the business market instead of home computing. When Chuck wanted to build an MSDOS machine with power, Tramiel fired him. He started Sirius Systems Technology and with his team won “Computer of the year” four times.

Actually, as written by Ian Matthews in a very interesting article, Chuck quitted Commodore twice in the late 1970’s. Each time he walked away from potentially millions of dollars in stock options and unpaid promises (like $1 for each PET). The first time, he went to work for Apple as what was billed to be their Lead Development Engineer. In an April 2006 interview with Commodore.ca, Bill Mensch explained “Chuck didn’t do well with structure… he clashed at Motorola and at Apple.”  Apples culture was cold and regimented; not well suited for a man of action like Chuck and after a few months he returned to MOS/Commodore. The last time Chuck returned to Commodore, Tramiel set up an R&D facility in Moore Park, Los Gatos, California so he could lead a small group of R&D engineers.

So fascinating…

The poor, dusty VIC-20

But let’s get back to my little old friend. In the gallery you can lurk on some pictures of how I managed to restore the little computer full of memories. While I still own all the manuals for my Amiga 500, no paper documents survived for my VIC. No power adapter and no RF tuner as well. Also some buttons were missing: I can remember one of them broken by my anger due to a too difficult 8-bit olympic ski videogame! But the other one, a grey function button, was lost in the darkness, whiloe the caps lock switch was stuck in a pressed position. The "Power" brown tag, around the red 5V led lamp (which I later discovered was burnt) was missing, and a massive amount of dust was everywhere, inside and outside of the micro-computer.

Only three small screws that I cleaned with sandpaper were keeping in touch the two halves of the case: a part of the yellow color of time, plastics were surprisingly in good shape. No dents and no missing corners. Some stains only and discolored portion of the upper part. I dismantled the keyboard, which deserved particular care after, paying attention to the wire ribbon and I separed the motherboard from the plastic case.

40 volumes peroxide cream (12%, yes, the one used by hairdressers) and a couple of sunny days (plenty of UV-rays for free) made the trick: the case was clean again and it recovered the original color, while the stains were removed by a gentle sandpaper whiping. I could find a suitable power adapter (the VIC-20 / 64's one is a weird thing spitting out 9V and 5V on two separate channels for the DIN plug) and I tried to revive the Vixen.

The 5mm, 5V red led lamp was gone, so I replaced it with a new, bright one, with a white clear lens but red in color. I could also pick up the missing keys from the Bay (not very cheap to be honest) and I replaced all of them, cleaning the whole keyboard after having all the keys in a dishwasher detergent for two days.

In my garage I could find a DIN and some RCA connectors, and following this diagram I could create my own cable to plug the VIC-20 back on a TV set, without having to rely on a RF tuning adapter. The power tag was find in Poland, while some isopropyl alcohol was used to clean the electronics.

I put all this together again and I plugged the homebrew DIN-RCA cable on a modern LCD TV set. Bam! The long forgotten cyan frame around 3.5 Kb of RAM devoted to the BASIC framework! I know that this could sound a little bit emotional from a grown man, but I was moved.

I bashfully typed LOAD, and the VIC, after 37 years, answered me again: PRESS PLAY ON TAPE...

2021-08-03 08-19-03 555 2021-08-03 08-20-00 548 The VIC chip. 2021-08-03 17-50-23 588 The logic board. Fixing the keyboard. Fixing the keyboard. Shining back again!


During this retrocomputing adventure I came accross a really interesting web site, hosting many resources on the VIC-20: it also offers access to the VIC-20 Registry. The site is designed and developed by Giacomo M. Vernoni, author of the book Commodore VIC 20: A Visual History. The registry is based on the serial number, and shows all the details of the registered VICs. Everyone, just like me, can add his or her VIC-20 to the registry by filling a form with all the information about the computer. Very cool initiative.

Working again in 2021!


Nessun commento

(optional field)
(optional field)

In questo sito si attua la moderazione dei commenti. Questo significa che il tuo commento non è visibile finché non viene approvato da un moderatore.

Mantenere le informazioni personali?
Nota: Tutti i tag HTML eccetto <b> e <i> saranno rimossi dal commento. Puoi inserire collegamenti semplicemente scrivendo un URL o un indirizzo e-mail.


Dal 2004 questo piccolo angolo di rete raccoglie gli interessi di ricerca e i lavori di sperimentazione digitale di Simone Garagnani in materia di cultura geek, ma soprattutto di Building Information Modeling, rilievi digitali ad alta risoluzione e computer graphics legata al mondo dell'architettura, dell'ingegneria e delle costruzioni. TC Project, è presente anche sul social network Facebook.


Welcome to these pages that host since 2004 Simone Garagnani's personal blog, a collection of nerd notes and geek experiences focused sometimes on Building Information Modeling, terrestrial laser scanning, digital photogrammetry and computer graphics applied to the AEC world. The TC Project is also available on Facebook.

Segui le attività in TC Project: Registrazione
Follow TC Project activities: Registration/login



GreenSpider plug-in for Autodesk Revit

Free download here (latest release)



  • English (22)
  • Italiano (4)
  • Ingegneria (21)
  • Architettura (27)
  • Design (6)
  • Ricerca e sviluppo (57)
  • Eventi (40)
  • Pubblicazioni (13)
  • Materiali didattici (11)
  • GreenSpider (10)
  • Berkeley (28)
  • Pixar (8)
  • Retrocomputing (7)
  • SGI (17)
  • Keio (3)
  • Serious fun (7)
  • Archivi

    Ultimi commenti

    SiliconSimon (Cray-1 - The home…): If someone is interested in my little Cray’s files, please PM me since I do not often read comments o…
    SiliconSimon (Cray-1 - The home…): Of course Mike, I sent you a PM!
    Robert (Cray-1 - The home…): If it’s possible, I would love to get the files from you for this project. I have a Cray-1 chip sitti…
    Mike (Cray-1 - The home…): Are the files still available?
    MojaMonkey (SGI VW540 @ TC La…): Hi Simon? This is a long shot but I was wondering if you have a copy of the SGI drivers required to…
    Walter (Cray-1 - The home…): Could I get a copy of the plans (in English)?