Written and Maintained by Gregory Nacu


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April 22, 2019Hardware

Modifying the uIEC Deluxe Daughter Card

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In late 2016, when I was setting up my workspace for Commodore computers, programming and all sorts of other retro mancave-style fun, I decided to build a couple of wood stands for monitors.

Here's the post, http://www.c64os.com/post?p=4. I got the idea from another site, BYTECellar. Anyway, they've turned out to be pretty great stands. The top surface is on an angle so it holds the display nicely facing up towards me, and conceals all the wires and other crap coming out of the back of the c128. I built a second one for a C64, too. The top surface has a bit that juts out beyond where I put the monitor too. This is a useful little shelf for pencils and programming notes.

But there was one annoying problem. I've got the uIEC with deluxe daughter card from Retro Innovations, which is a nice little implementation of SD2IEC. The deluxe daughter card plugs into the cassette port for power, and to anchor to the back of the computer. And then the uIEC/SD plugs into it via a 1x13 pin terminal block. The daughter card includes two IEC ports on the bottom, 4 momentairy push buttons on long the left side, for reset, disk image swap, etc. Plus, the daughter card has two female headers for the uIEC/SD to plug into.


One of the headers is oriented horizontally, backwards, or away from the back of the computer. This orientation is, in my opinion, the most stable. Because the uIEC itself ends up resting on the IEC cables below it that are connected to the daughter card.

The alternative orientation is vertical, with the uIEC sticking straight up into the air. This has always felt a bit less stable to me. As the whole uIEC is just standing upright in the air with only the single row of pins keeping it there. One advantage to this orientation perhaps is that it's easier to put in and remove the SD cards, plus there are 3D printable enclosures for this orientation that help make it more stable too.

The problem I suddenly had is that the new wooden stands are designed to cover over the back end of the computer and keep it neatly tucked away. In this case though, it is my uIEC/SD that is neatly tucked away… so far away that it became a big pain to change SD Cards.

The 3rd Header

Fortunately for us, Jim Brain had the forethought to add a third set of throughholes for another pin header. This one does not come with anything connected to it by default, but you are free to add your own.

Here's what the Deluxe Daughter card looks like, unmodified. You can see the four buttons along the right side, the horizontal pin header along the back and the vertical pin header in the middle. Additionally, you can see a row of 13 holes slightly closer to the casette port connector. Oh yes, one more thing, there is a mini USB port on the left hand side too. This is for powering the daughter card from a USB port, rather than from the 5 volt line on the cassette port. I suppose this is to take the load off the computer if there is already too much draw.

Original, unmodified uIEC/SD Deluxe Daughter Card.

The daughter card actually has one other nice little feature, that you can't see pictured here. On the bottom side of the card is a jumper that connects the IEC reset line from one port to the next. If you remove the jumper, or only connect it to one pin so it doesn't bridge the pins, then a reset signal on the IEC Bus will not get propagated to daisy chained devices.

I actually find this feature very useful, because I put a CMD HD downstream from the uIEC, and then I use it for developing C64 OS. But, because I crash frequently, and reset my c128, that ordinarily would reset the CMD HD. It is more convenient for me if the CMD HD is not reset, so it retains its default directory and partition and any other status. Plus, the CMD HD has its own front–panel reset button if I need to reset it.

The idea is to add a third header to the deluxe daughter card, via that row of empty holes. And to angle this pin header foward, towards the cassette port connector. This way, when the uIEC is plugged into it, it will rest on the back of the c128 itself but with the socket for the SD Card pointed forwards.

Let's get to work!

Using a dremel to cut a pin header down to 13. Using a dremel to cut a pin header down to 13, close up.

I bought off eBay a bag of 1x50 pin headers. They came from China and the whole bag only cost like 2 dollars. I originally bought them for some other use in C64 Luggable, and now I've got left overs.

The easiest way to get a header that's 1x13 (an unusual size) is simply to dremel off a piece that size. Interestingly, if you look closely at the picture of the daughter card above, it looks to me that the pin headers that came installed from Retro Innovations were also manually cut to length. But I didn't even notice until I went looking for it.

I love my dremel, it's such a versatile tool. In this case, I used a bit of masking tape to hold the piece to some scrap wood and about 2 seconds of cutting later you've got yourself a 1x13 header. The cut usually results in the loss of one pin. So, a 1x50, for example, could give you 3 of these (14 * 3 == 42), and you'd have a bit of left over scrap for smaller headers.

The pin header cut down to size, top view. The pin header cut down to size, side view.

There we go. Give them a little sanding to smooth out the dremelled edge and they look like they were purchased at this size.

The only thing left to do is solder it on, but at an angle. I plugged the uIEC into the header, stuck it in the holes and angled it forward to get an idea for where it should sit in order to rest nicely on the back of the c128 case. Then I waded some paper in and used some tape to hold it in place. During soldering the uIEC was not connected, because, well, it doesn't need to be there so why risk damaging it, right? There are no other electronics components on the daughter card to damage. It's just a matter of ports and wiring.

Here's how it looks after soldering it on.

The pin header soldered on, top view. The pin header soldered on, bottom view.

A very simple addition. You can see in the top view how it is angled forward towards the cassette connector. And on the bottom you can see my amateur solder work. Ah, you can also see that jumper I mentioned earler for the reset line. There are a number of other through holes and solder pads on this daughter card. I'm not sure what they're all for. But, I like the fact that it leaves a few things open for easy additions and simple modifications.

But the proof is really in the end testing. Let's see how it looks when it's hooked up to the c128. Can I get my hand in there to reach the SD Card? Is it easy to swap the card without needing to move the computer, and without frustratedly fumbling around? Let's see!

Installed at the back of the c128, underneath the display stand. Easily reachable by my hand without needing to move anything.

Looks like it works. I still have to focus when putting in an SD Card, usually I have to hold it in my hand the right way before putting my hand under the display stand, but, it's way better than before.

So there's a simple little mod you can do to the uIEC/SD Deluxe Daughter Card.