VIC-20: It’s Alive!

Ah, the things middle aged men do to recapture their youth. Some buy a sports car and date women half their age, while others buy old stuff and play with it… I, with my Commodore VIC-20, would be the latter. Don’t get me wrong, I would buy a Datsun 240Z in heartbeat (because it’s the coolest looking car since, like, ever!) if I thought my wife wouldn’t have my head keep on rolling after 240Z stopped in the driveway. I digress…

My VIC-20 did not come with any extras, no cords, no adapters, no drives, nuthin! Meh, what can you expect for $20? I certainly did not expect that it came with a manual, so kudos to the previous owner for that. All I had was the knowledge that the machine was in good shape and that it did work the last time it was tested, whenever that was. That was fine, because I primarily purchased it so that it could grace my desk with its retrotastic presence. However, I did want to see if it worked and if it did, I would eventually get some stuff to use with it (ultimately, I would like to get a Commodore 128 to retrocompute upon).

The first thing I needed to do was scour my house and find two “wall wart” power adapters that could provide the (5VDC/1.5A) and (9VAC/1A), as they can be combined to provide the power that the VIC20 requires. This is by far the easiest and cheapest way to power a VIC20 or C64 if you have a fair amount of tech junk kicking around. I had all but given up on scrounging the 5V when I decided to take a closer look at the broken adapter (kids broke the USB connection) for my Blackberry Playbook, because my old eyes really were able to make out if it was 1.0A or 1.8A written on in super tiny letters and I none of my other adapters have enough amperage. Sure enough, it was 1.8A. Combined with the 9V supply from one of old Lynksys routers, I had the power!

As part of my initial research, I looked at purchasing a 7 pin DIN connector for power plug, but I couldn’t find any locally and the ones I found online tended to have crazy shipping prices. $2 for the item with $20 for shipping does not make any sense,… My experience with buying very inexpensive, yet high quality components from China on Ebay has been great, apart from the whole “slow boat from China” aspect of the shipping, so I will probably go that route in the long term. In the mean time, decided to test the VIC-20 using some hand built DIN pins.

he following is a series of pictures and steps demonstrating how I crafted a plug for the Linkysys adapter (rather than wreaking it), the pins for the power and video cables, and how I attached them to the machine.

Creating a Plug for the Linksys Adapter
1. Get spare piece of mutli-conductor wire. This is from an old PC power supply.
2. Use wire cutters to cut the insulation a few inches from the end.
3. Slide the shielding down, exposing a gap in center.
4. Bend the wire over the outside, ground part of the plug.
5. Use a zip tie to hold the loop closed.
6. Remove the power plug, tin the loop with solder so that it holds its shape, and outer part is finished.
7. Take another piece of wire and strip an inch of insulator from it.
8. Fold the exposed wire over on itself and twist it together tightly with your finger. This will is the center post of the plug.
9. Twist the center post some more with some pliers to make sure it is strong, then slide it into the hole on the adapter to make sure it fits. If it is too large, squish it a bit with some pliers. If it is still to larger, use a lower gauge wire or start over and trim some of the strands off this wire before bending it over.
10. Tin the center post with solder and make sure it still fits inside the plug’s hole (squish and shape with pliers as needed).
11. Slide the plug into the wire loop, stick the center post into the plug, and use a zip tie to attach the center post to the loop.
12. Wrap in everything together in electrical tape, being careful to not leave any exposed metal.

Making the Connecting Pins
1. Find some spare bits of copper grounding wire from 120V home wiring. I used two gauges, with the slightly smaller one being used for the video cable.
2. Cut six 1.5″ pieces and remove any insulation.
3. Use a hammer and a solid surface, such as an anvil or other heavy piece of metal, to slightly flatten 1/4″ on the end of each pin. This makes it easier to solder the wires to the pins.
4. Sand or scrape off any corrosion on the flat part of the pins.
5. Tin the pins and the wires and solder them together. You will need to hold the pins with a clamp of some sort, as they get burning hot in an instant!
6. When the pins have cooled down, slide some wire-shrink over them and the wires and shrink it (using heat).
7. Mark the ground on the 5V pin differently so that you can remember which is positive and which is ground.

Making the Video Cable
1. Cut the end off an RCA cable.
2. Solder the pins, as above.

Connecting the Pins to the VIC-20
Normally one does not have to deal with pins when plugging in a cable, but the reality is that many connectors are stuffed full of pins and it’s those pins that are doing the real work. With that in mind, if we know what pin goes where, it’s not a big deal to simply slide the pins in one at a time by ourselves. Here is a diagram of the Commodore 64 / VIC-20 power supply:

Keep in mind that the picture of the socket on the bottom left is what you see when looking at the VIC-20, while the circle on the bottom right is what the 7 pin DIN connector on the end of a standard power cable would look like if you were holding in your hand. When manually inserting the pins, it easiest to just refer to the numbers on the socket.

The two 9V pins slide into the top most holes. The 5V ground slides into the bottom middle, while the 5V positive slides into the number five hole immediately to the left of the bottom middle hole.

Connecting the video cable is just as simple. Here is the layout of the video socket, as you would see it when looking at the back of the VIC-20:

Slide the ground pin into ground and the center “signal” pin to hole 4, then connect the other end to the composite in of the TV, monitor, etc. that you will be displaying the VIC’s upon.

And now for the “pre-flight check”, where I opened up my VIC-20 to make sure nothing had been living it, etc.

And the setup, using the composite in on the TV tuner in my PC as a monitor…

And the big reveal!

It works!

And with that accomplished, it’s time to find at least a “Datasette” for it so that I can save and load programs, because the VIC-20 is not so useful without that capability. I am probably better off to use the emulator for now, with the VIC-20 keyboard as a visual aid. I am not sure which is harder, typing on the real and unfamiliar VIC-20 keyboard or trying to figure out what key does what on my PC keyboard when using the emulator… 🙂

Typing in a BASIC program from the manual (left) and running it beside the emulator (right).

What a nerd am I! lol…