C64 LUGGABLE PROJECT

Power Preparation

Commodore computers usually have multiple components that each need to be plugged in. This leads to what I lovingly call the multi-headed beast. Your C64, its monitor, a CMD HD, a 1541, a 1581 and a set of speakers, each with its own power brick and cables is 6 power supplies. For desktop systems I like to hook these up to a single power bar with its own on/off switch. So I can press one button and everything powers up at the same time.

This is impractical for an all-in-one luggable. The obvious choice to power our luggable c64 is an AT Power supply. These supplies are powerful (~300W), relatively lightweight, and abundantly available on ebay and other online vendors. They have a fan to help keep them cool, a push button for power and a multitude of connnectors, the most common of which is called molex and is the standard on most internal hard disk mechanisms. For our purposes, you want to make sure you get the kind with the passthrough AT power port. This port is a direct feed of 120 VAC from the wall outlet, but it is also controlled by the main power switch.

AT Power supplies are great. But there is just one problem. They output 5VDC and 12VDC but the C64 requires 5VDC as well as 9VAC. There are some electronic solutions to this problem, but none of them is a commercially available product that you could just go buy. A practical alternative is to use a standard wall wart designed to output 9VAC. LinkSys and USRobotics both made lots of these. You can easily acquire one of these from ebay, you just want to make sure it's 9 VAC and at least 1 AMP. If you can, make sure you see those specifications in the photo of the product. Sometimes people accidentally mislabel as 9VAC when the photo clearly shows the output is 9VDC. The connector is completely irrelevant because we'll be replacing it.

Now that we know we need a 9VAC wall wart, it becomes clearer what use the AT Power passthrough will be. Traditionally this passthrough is used for powering a display. You just use a special AT power cable that's male on one end and female on the other to connect the display's power port directly to the AT supply. When the AT supply's power is switched on, power is also sent to the display. We are going to do exactly this to power our internal display, but we're going to use a really short (~1') AT extension cable. The only thing is, we need to power both the display and the 9VAC wall wart. In order to handle this we want a special kind of splitter and a very short regular electrical extension cable.

All three of these are somewhat unusual, but are readily available on either ebay or Amazon for a few dollars each. The splitter is male-AT on one end and splits to female-AT and female-AC on the other end. They will connect together pretty much like this.

C64 Power Cable

Next we need to make our C64 power cable. In order to do this, I ordered from ebay a bunch of power jacks. The C64 takes a DIN 7 jack, and the 1541/1581 takes a DIN 4 jack. Search on ebay and you'll find that they sell all varieties and pin configurations, usually in lots of 5, 10, or more, for pennies a piece. I got a pack of 10, five of which are the DIN 4 kind and five of the DIN 7 kind. They shipped direct from China and cost about $3. You can't go wrong.

You will also need a package of 4 pin male molex connectors. These are usually white, with 4 pins in a row, and are suitable for connecting to the female molex connectors found at many of the ends of the AT supply's power lines. You could just chop the female molex connector ends off the AT supply and solder the free wires directly to your DIN 7 power jack. However, one of the goals in C64 Luggable is to have as many of the parts as possible swappable. Making a DIN 7 to Molex 4 cable means you can just plug it into the AT supply. And if you want to later use this supply to power a C128 you can just make a different cable. Or if the supply dies, you can just replace it and plug the old cable into the new supply.

I also had a package of male and female RCA connectors, so I didn't need to buy any more of those. They will be used for connecting the 9VAC wall wart to our C64's new power cable. The molex connectors and RCA connectors are all available and equally inexpensive from ebay.

Next comes the soldering part. And I am not good with a soldering iron, so this was a frustrating experience for me. However, I muddled through. The most important part of this is making sure you get the pins of the DIN 7 jack right, according to what the C64 needs. If you get this wrong, you could seriously damage your C64. The first image below shows the pinouts drawn on paper. The pins of the DIN 7 are numbered quite oddly, they don't come in order. 6 and 7 are the two pins closest to the notch, you can think of these as the pins at the ends of the curved set of pins. These are the 9VAC pins. The good news is that you just connect the two sides of the 9VAC power cable to these, and it doesn't matter which side is which. The only thing that matters as far as the 9VAC is concerned is that they're of opposite phase.

The bottommost pin, the pin opposite the notch is one of three ground pins. But it's the only one that needs to be connected. The convenient part about wiring this one up is that it too is symmetrical so you can't mess it up. Typically in an AT supply the black wires are ground, so I used I black wire.

The trickiest part comes next. Pins 4 and 5 come on either side of that middle pin 2. Both 4 and 5 are for +5VDC. However, only pin 5 should be wired up for a C64. When you've got the male power jack sitting on the desk, the pins should be down so the solder ends are up. With the notch at the top, pin 5 is to the left of the middle pin 2. In an AT supply 5VDC is typically red, so I used a red wire for that.

The cable of the 9VAC wall wart is much longer than it needs to be, so I cut it down to about a foot. Then I used an additional 5 or 6" piece cut from that cable to make the C64 power cable. The male RCA jack should be soldered to the 9VAC lines of the cable with the DIN 7 jack at the other end. And the female RCA jack should be soldered to the end of the wall wart's truncated cable. It really doesn't matter which way these are wired up, either side is the same as the other with AC power.

Make sure you slide the DIN 7 and RCA protective covers onto the ends of the wires before soldering on the connectors. When soldering a molex connector, what you get is a string of connected pins. Every pin is the same. You just solder a wire into each of two pins. One black for ground, one red for +5VDC. After you've soldered on the pins they get inserted into the molex connector, and click satisfyingly into place. Once in place they are very difficult to remove, and it's very difficult to solder anything to them once inserted.

The pins of the molex connector should be labelled. But if they're not, there is a ridge, or a bump, between pin 1 and 2. Pin 1 is for 12VDC, pin 4 is for 5VDC and the two middle pins are both ground. Insert the pin with the black wire into either of the two middle slots. And the pin with the red wire into slot 4, that's the one farthest from the ridge. You should end up with a cable like this:

USB Power Cable

We haven't yet discussed it, but the way to connect the SVGA 15" LCD display to the C64 is with a very small S-Video to VGA adapter. I'm using one I found on ebay by Portta. I wrote a review of it in the blog. It is powered by a USB cable. This is convenient because USB chargers are a dime a dozen, they come packaged with every modern mobile device. It's also convenient because USB ports have 4 pins. 2 for data transfer, 1 for ground and 1 for +5VDC. So it will be a snap to make a molex to USB cable.

In addition to the molex connectors and DIN jacks, I also buy a bag of female USB-A connectors. They came to about 10¢ a piece, but you couldn't buy less than 10 or 20 at a time. The USB connector has a notch on one side, this is closest to pin 1 which is +5VDC. Pin 4 is on the opposite end for ground. Pins 2 and 3 are USB data pins and can be left alone. The other end of this cable is connected to a male molex connector exactly as described above.

1541-II/1581 Power Cable

There will not be any internal CBM disk drive in C64 Luggable. However, it the name of expandability I will very likely want to have the option of hooking up a CBM or CMD drive external to C64 Luggable. But what I don't want is to need a power brick and a free wall outlet to power that external drive.

Wouldn't it be so much better if we could power an external disk drive off the AT supply that's built into C64 Luggable? The 1541-II and 1581, as well as the CMD HD and CMD FD2000 all use the same standard DIN 4 power jack. Conveniently, the pin out of the 1581 power jack is printed directly on the top of the 1581 power supply. Pay attention though, the pinout diagram I'd drawn on paper for the C64's power port is for the female port on the C64 itself, this pinout is the male pinout of the power supply, so it's the mirror image of the female power port on the drive.

The 1581 power supply supplies both +5VDC and +12VDC. My guess is that the physical mechanism, the spinning motors and other moving parts require 12VDC, and the circuit board requires 5VDC. In any case, this is easy to provide because the AT Supply offers both. The red wire on molex pin 4 is 5VDC and the yellow wire on molex pin 1 is 12VDC.

This cable is going to be available outside the chassis of the C64 Luggable, to hook up an external drive, therefore we want this one to have a proper shielded cable that looks professional. I happened to already have some cable lying around. Wiring it up is just like wiring up the C64 power cable, but it doesn't need the 9VAC.

Summing Up

So here are all the power parts and cables we'll need. The AT passthrough port is connected to the splitter. From the splitter we've got one cable that will go to the display, and the other goes to the 9VAC wall wart. The C64 power cable is connected to one molex connector and to the 9VAC wall wart. Another molex connector is used for the USB power cable for the S-Video to VGA converter. And there is at least one free molex cable for the external drive cable, although we don't need to hook this one up until we need it.

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Last modified: Sep 20, 2022