Housing and wiring advice

[James Harland]

Hi everyone,

I got a blue box (smaller than the Orton/Zed one, 195x165x90ish) as a housing for my Classic ][, and I'm pretty happy with it (I even stuck the RC2014 sticker on it which feels like a big step), but there are a few things I'd like to ask:

• The FDTI adapter sticks up more than I expected, especially with the end of the USB cable, and it is under a bit of pressure even with the hole I have made for it in the (cardboard) 'back panel'.  Is there a ribbon cable I could use to separate the adapter from the board, so I could make a neater USB C hole in a future back panel?
• For now I've just cut a hole in the 'back panel' so I can stick my finger in and press one of the reset buttons. How do I go about extruding the reset button, so I can either have it on the back panel or somewhere else? I'm aware this is probably a really basic question, but I'm quite new to electronics.
• Similar question for the Basic/Monitor jumpers - is there any way of making that a switch rather than the current state of affairs which basically involves removing a board to get at the jumpers?
• Finally the back panel. I'm fine with the cardboard one for now (the RC2014 was in a cardboard box until now with BluTack feet), but what kind of material do people recommend making a more permanent one out of? I'm also very early on in my furniture making career :-D
  

I attach a couple of pictures, because I'm pleased with this evolution of my RC2014, and so you can see what I mean about the FDTI adapter and reset button hole. for now the board is on M3 rubber feet, but if I can get the Basic/Monitor issue sorted so I don't have to physically remove the computer from its box, I might look into getting some metal bits for my drill and fixing the backplane in place with standoffs.

[Spencer Owen]

Hi James,

Looking good so far :-)

• Have a search for "Dupont Cables". These are normally coloured ribbon cables with connectors on them at 0.1" pitch to match the pins / sockets used on the RC2014. That will allow you to mount the adapter remotely.
• The reset button connects the reset pin to ground to, well, reset it. You'll see that there's a reset line on the backplane as well as a ground. So if you are not using the other slots on the backplane, simply solder a push button to some cables and connect those to the reset and ground pins. (If you fit the extra sockets that came with the kit then you can use Dupont Cables here too!)
• For the Classic II this is fairly easy as the only two images on the ROM need all three of the ROMs address lines either pulling all high or all low. So if you short the three middle pins together then you just have 3 connectors you can put in to a DPST (Double Pole, Single Throw) switch. Again, Dupont Cables might help here. [Note that for other RC2014 models, or anybody that has put additional images on their ROM that this will not work.  You would need to bring the connectors out to three individual switches]
• Hey, cardboard is fine :-) Also look at hardboard, perspex, thin wooden panels, or even design your own PCB specifically for the job!

Spencer

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[Ed Silky]

For panels, besides cardboard/posterboard, two common options are sheet aluminum and ABS plastic sheet. Aluminum isn't really too hard to work with. I typically use 6061/T651, 3/64" (18-16GA, 1.0-1.3mm) for small/medium panels. For ABS, I get sheets that are textured on one side (typically black or white). ABS sheet is harder to find in 3/64", so you usually have to decide between 1/16" or 1/8". You can get both aluminum and ABS sheet on Amazon. For stores, try craft stores and hobby shops for the ABS and home improvement stores for sheet aluminum.

For either, it can be very helpful to use your cardboard or heavy paper as a pattern. If you don't have a lot of tools, a lot can be done with drills, a coping/jeweler's saw, and small files (a small triangular file is a good one to start with).

-Ed

[James Harland]

Thanks Spencer and Ed. The Dupont cables are a game changer, I have already managed to fix up both the FDTI cable and the Basic/SCM wires with them, though for now I am using the jumpers onto batches of three jumper wires selotaped together (in the right order - not sure if that was essential). I will work on more permanent solutions as time goes by, but I'm very happy that for now there is no structural pressure on the computer, and that I can much more easily switch between Basic and SCM.

About making a more permanent Basic/SCM switch - so if I have understood your advice correctly Spencer, the three pins in each row (0, middle, and 1) can each be connected to the same place (the same row on a breadboard in my mind), and then the switch is made to choose between connecting the top row (0) to the middle, or the bottom rom (1) to the middle. But if I had a more complex ROM setup later, I would need DIP switches for each column?

[James Harland]

As some trivia, it turns out Dupont cables used to be called Berg cables, but I was sold them in Kazakhstan as Arduino cables. Dominant firm names change, wires stay the same :-D

[Ed Silky]

>  Dupont cables used to be called Berg cables

That is how I remember them. Berg made the connectors that are (were) used. Berg headers, Berg connectors, and Berg Jumpers (the little 2-pin jumpers that go on 2-pin (Berg) headers for selecting options).

-Ed

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[Spencer Owen]

On 12/11/2025 05:29, James Harland wrote:
> About making a more permanent Basic/SCM switch - so if I have
> understood your advice correctly Spencer, the three pins in each row
> (0, middle, and 1) can each be connected to the same place (the same
> row on a breadboard in my mind), and then the switch is made to choose
> between connecting the top row (0) to the middle, or the bottom rom
> (1) to the middle. But if I had a more complex ROM setup later, I
> would need DIP switches for each column?

Hi James,

Yes, you've got it. Excuse my sketchy drawing, but hopefully the
attached image will make things more clear.

Spencer

[James Harland]

Great, thanks Spencer! It seems I have a lot to learn about switches - I do have some in my collection of electonics gubbins, but it seems they are the wrong kind. For now I have the three bundles of wire plugged into a breadboard, and I just use a single jumper wire to choose Basic or SCM - still way more convenient than the original method. I'll try to find the right kind of switches on AliExpress for a more permanent solution.

Now as for the reset button, I need to think about future expansions to the computer before I use a whole slot up just for reset. If I go for the CP/M upgrade at some point, how many extra slots does that take up? Would it be possible to desolder the original reset button and wire things up from there instead?

[James Harland]

Also this might be too vague / optimistic a question but are there any standard things for holding bits in place inside a box like this? So now the FDTI connector is not being crushed, but its now just sort of floating around inside, and I can't easily plug/uplug the USB C for example . Are there things which grip the edges of little PCBs like that connector which can be used to hold them in place?

[Ed Silky]

Hi James,

The switch Spencer shows in his sketch is a Single Pole Double Throw (SPDT) toggle switch. That should help your searching on AliExpress.

-Ed

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[Ed Silky]

Hi James,

There are a number of ways to hold electronics in place, but for small bits (like the FTDI adaptor) you might consider double-stick foam tape or velcro (hook-n-loop) tape. Those typically weren't used in commercial devices, but have been used for a long time in things like RC airplanes/cars and they work well for smaller parts without requiring holes, screws, etc. Actually Velcro can be used on fairly large boards if a few strips/squares/circles are used.

-Ed

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[James Harland]

Thanks Ed. So I'm a bit confused now, as Spencer said double pole, single throw, and you are saying single pole double throw. From Spencer's picture and from your name, I suppose I need this kind? This seems to make sense to me as I need ON - ON (Basic or SCM), but there is no need for OFF.

[Ed Silky]

That switch is correct.

Without going into a long description of different switches, a:

1. Single Pole Single Throw (SPST) is like a typical light switch, where there is a single switch controlling a light. It has two connectors and it connects them (is ON) or doesn't (is OFF).
2. Single Pole Double Throw (SPDT). This connects a single pole (the center terminal) to one of two other connectors (double throw).
3. Single Pole Triple Throw (SPTT), though you might find it called a Single Pole 3-Position Center-OFF. This is similar to the picture you have, except that it would say ON-OFF-ON on the side. This will connect the center terminal to one of the two side terminals, or to neither/none of them.
4. There is a variant of that switch, where the switch stays in the center position, and you press it to one side or the other, then it returns. That is a Center-OFF Momentary.

For all of those, there was a single center connection, therefore Single-Pole. If you have a switch that looks like your picture, but has a second row of pins, that is a Double-Pole switch. It then has all of the same combinations as I described above, but has two separate circuits that are switched at the same time (DPST, DPDT, DPTT (or DPDT-CO). Of course, they make 3-Pole, 4-Pole, etc. but they are less common.

Hope that helps.

-Ed

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[Phil G]

JH: >> The FDTI adapter sticks up more than I expected

Mine is mounted the other way around, on the back of the board. Made more sense to me - the serial cable feeds neatly between the serial and CF cards

and the cabinet lid has plenty of clearance:

 

[James Harland]

That was a good decision!

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[James Harland]

I've now got round to attaching my RC-2014 to its box with metal standoffs. First time I've ever drilled metal, and I also had to cut some plastic as the plastic frames on the inside of the case were in the way of the standoffs sitting flush. You can also see that I have embraced Dupont cables! They also actually came in handy trying to resurrect one of my HX-20s.

[Ed Silky]

Very good James.

You'll find that working with aluminum isn't too hard. Just make sure to keep your electronics away from it while you are drilling and cutting, and then clean things up well before bringing the electronics back. The tiny little aluminum 'dust' loves to short things out! Using a vacuum and some masking tape (to pick up little aluminum specks) works well. Brushes/brooms just tend to spread the conductive dust around.

-Ed

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[David Lochlin]

James, a good practice with the Dupont cables is to buy an assortment of empty connector housings(ones without  the wires and contacts inserted) say 3 , 4, 5 and 6 way. Then you can use a pin or sharp needle like object to carefully lift the little plastic tab on your single dupont connectors and slide the wire and contact out. Then you can insert them in the multiway shell until it clicks into place but making sure it's in the correct position. Do that for your six wires (for the serial connections) and you end up with one connector and you never have to worry about which order they need to be in. You can even fit a small label on the connector housing and put a dot or mark to show the polarity so it doesn't get plugged in backwards.

Attached is a pic of one ZI have for a different Z80 SBC I have.

Dave

[Ed Silky]

Ever wonder what size the actual Berg pin is? Or how much current it can carry?

Here is a datasheet for the headers: https://cdn.amphenol-cs.com/media/wysiwyg/files/documentation/datasheet/boardwiretoboard/bwb_bergstik.pdf

    and: https://cdn.amphenol-cs.com/media/wysiwyg/files/documentation/datasheet/boardwiretoboard/bwb_econostik_254headers.pdf

Here is the housing (4-pos in this case): https://www.amphenol-cs.com/product/65039004lf.html

The jumpers (shunts): https://cdn.amphenol-cs.com/media/wysiwyg/files/documentation/datasheet/boardwiretoboard/bwb_dubox_shunts.pdf

The 'OFFICIAL' hand crimp tool: https://cdn.amphenol-cs.com/media/wysiwyg/files/documentation/datasheet/boardwiretoboard/fci-basics-handtool-dubox-ctw.pdf

-Ed 

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[David Lochlin]

Those official crimp tools are hideously expensive, but they are designed to do thousands of crimps, if not more. Not viable for us hobbyists who want to make one every now and then. I have tried a lot of alternatives and have one that I like but have 3 or 4 that were a waste of money.

Dave

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[Ed Silky]

Yep, it's hard to find one that works well. I find it particularly frustrating, because I worked as an engineer at a company where we had all the 'official' tools. In fact, for a couple of the connector pins (those Berg pins being one of them) we had electric/automatic machines that had a roll of the connector pins/sockets. You put a piece of wire in one hole and tap a foot switch and it would strip it correctly and then put it in the other hole and tap the foot switch and the connector was on the wire.

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