retro computer kit

THE µKENBAK-1

Back again with another retro computer kit from the same creator as THE ALTAIR-DUINO, a small quick kit in the µKENBAK-1. The µKENBAK-1 with the µ in front denotes one of the earlier versions of the kit. This is smaller than the original computer kit, compared to the full-sized replica or nanoKENBAK-1 now offered by the creator. This is a small, and simple kit. Running off an Atmel processor (same as Arduino), this little recreation offers a fun, simple front panel, and relatively quick assembly.

Compared to some of the other kits that have been posted here, this one is straight forward to put together. While you have the classic soldering, the kit is all through hole components and is a pleasant hour or so to put together. The most time for me in putting the kit together actually came down to getting the PCB with the stand-offs in the case and lined up with the back holes. This proved to be a difficult, and time-consuming process. You need to pre tighten them on the front panel, which then slides into the case, and line them up with the back holes. Between the standoffs being plastic and wanting to strip, and them wanting to wiggle all over, most of my time went into this instead of soldering. In the end, I got 5/6 in place and called it a day.

Evil Stand-Offs

The creator of this kit shows his experience in creating these kits, in little details, which make the kit a nice experience; one example is the usb extension cable which gives you an easy connection out the back is the perfect length to do the job but not be in your way. Another is the instruction booklet coming with a bunch of examples on how to use the computer, right after the assembly instructions. These instructions come in a nice spiral book included in the box.

The creators website, https://adwaterandstir.com/kenbak/ also goes into detail about the creator of this machine, (the original one in the 1970’s), and its history.

This is one of the easier kits I have done, but enjoyable in its ease to put together. I would recommend this kit to someone who is looking to get started with these kits.

Briel Computers Replica 1 Plus

Kit

I recently ordered the Briel Computers Replica I Plus, a Apple I clone. Instead of the originals big board to do a lot of NTSC generation, it uses a more modern single chip. The shipment came in a small box, and with everything I needed. The creator of the kit did a great job including everything you need, down to including an anti-static strap! The project came with some solder, but not nearly enough for everything, I think it was thicker to go with the structural points. Briel Computers sells the kit through ReActiveMicro.com. At $135 it is one of the less expensive kits I have had, but also comes with just the board. If you want a case that needs to be 3D Printed (more on that later).

ReActiveMicro points you over to the Project Wiki for more information, there is a ton there and a link to someone putting the project together. I found this easier to follow along and do than reading the instructions.

The kit was fairly easy and straight forward; I ran into a few small issues around the PS/2 port since the solder points are close together. Getting the few connector ports in can be a bit difficult with a few tiny pins and getting them in the board. As long as you have patience, then you can get through it.

I got it all together, and the board started the first try. I did have the same issue the person who made the video had; I was getting a lot of noise and characters added to the screen. I reflowed a lot of the sockets, and made sure all the socketed chips were fully seated. That cleared up the garbage at startup. The wiki also has some other notes on noise issues the board can show.

I also could not find a PS/2 keyboard in the house, and all the USB keyboards I had didn’t seem to like the USB->PS/2 Adapter. I am not very surprised by this because I didn’t have any very simple, older keyboards.

The USB port that is used for power is also a serial device for a PC/Mac. I plugged into that and got the serial driver working from SparkFun website, they produce the module. Then the output worked well, and I could enter BASIC on the board!

Case

I wanted to put the board in some sort of case, and after searching online I couldn’t find any. I thought I would throw something together quickly that I could put the board in. I took some measurements and threw together a V0 of the case. One small issue was I didn’t account for the RCA jack the video comes out of little let that sticks out. Instead of spending another 7 hours printing a new one, I used a little saw I have to cut a hole out.

Part of my thought of creating a case was to have something I could put the board in, then store it in a cabinet or shelf and not be worried that the board would get damaged. I also made a case that can go over the entire unit to protect it in storage.

Again, looking back small design things could have been changed, like flip the name of the project in the case, so looking at it in the protective cover, the text would be right right way. Getting the scaffolding out of the protective case was not the easiest of things. I designed the protective case with a rail that brings the edge of the mounting board into a locking position when you slide it in. I have to say, that was a nice aspect to the design. It took over 6 hours to print though.

Finished Front

IMSAI 8080 Replica Kit

Continuing the journey of retro computer kits, I emailed the creator of the IMSAI 8080 kit over at https://thehighnibble.com/imsai8080/#overview when I saw the kit he had, but didn’t know if any were available; then one day out of the blue get an email saying a kit is ready for order! They come out in batches, this makes it take a bit to get them sometimes. To start off I can say this is one of the more well put together kits I have gotten. I was a little worried when I looked at the instructions and it mentioned a lot of part numbers and no photos of the setup; then I realized I had missed a link to a video that walks through the whole process, making it much easier.

The Kit

The kit is one of the more professionally put together kits I have done. From the metal case the system sits in, to the cut out cardboard all the parts come in. The creator, Dave, put a lot of attention to detail into everything. This kit includes everything from serial console lines on the back, to the micro controller having a WiFi antenna, which you can access over WiFi. The shipping box is also the correct size for the unit, you can use it as storage after you are done with the project. This kit comes with what you need ready to go and be put on the board (except solder and flux); some of the kits I have had in the past have required painting. You do pay a bit of a premium for it, but I think it is worth it. The kit also allows RS-232 connectivity or USB directly into the ESP32 controller.

Assembly

I will start off saying the hardest part of putting the kit together is at the beginning. There is a tiny chip for memory and that needs to be surface mounted to the board. This involves getting a small amount of solder onto the pads and then heating them with the chip on it. I accidentally bridged 2 pads and spent a chunk of time getting the tiny amount of solder off. After that part is over, you move onto the micro SD card reader, this is a similar surface mount; yet either I got better after doing the first one or got lucky, that was put down relatively quickly.

There is a diagnostic program you can run at that point to check if what you have soldered so far is working (which is fantastic), after that it is time for you to press on to soldering all the LEDs and their corresponding pieces. This part of the process is much like other kits of this type you may have done. It takes a while, but is a straight forward process.

In the end you sandwich the board together, and get it screwed into the case. There are a few parts where its gets a little tricky if you don’t want to have to pull the whole thing apart, but the video guide easily walks you through it.

Software

The software for the unit is great; the projects website, thehighnibble.com has instructions on how to use it. Similar to other projects there are certain switches you can flip to send the system different commands. But then, my favorite part is you can connect to the device over WiFi (either adhoc or with a AP) and then see the terminal. This allows you to leave the system on a shelf or a desk, and play with it at the same time. This interface also allows you to edit which “disks” are inserted into the system, to easily change images.

Overall it was a very enjoyable kit, other than the first little bit with the surface mounts. I think any beginner could do it once it is past that point. The resistor and LED soldering is straight forward. The metal case, and back clear acrylic make it stand out and look great. The WiFi and web interface put it over the top, as a it you can play with and connect to easily.

Powering up! It’s very shiny

Altair 8800 Kit

This post will be a bit more brief than some of the others, I was relaxing around Thanksgiving and put this together. Only afterwards did I realized that I was having such a good time, that hadn’t taken too many photos.

The kit comes from Chris over at https://www.adwaterandstir.com/altair/. The version I have is The Altair-Duino v1.4, which came in a bamboo box. There are now other versions, some with acrylic cases! This post will be about version 1.4.

The Kit

The kit comes with all the parts you need inside the box. The main controller is an Arduino, hence the name The Altair-Duino. There is an SD card that you bend the prongs on (more on that later) which holds the disk images. This is a fun straight forward kit, that comes with everything you need minus solder. The Arduino came with the firmware it needed, and the SD card came with disk images preloaded onto it.

Assembly

The kit comes with a spiral notebook of instructions on how to put it together. These are great, color photos of step by step what to do. You can see them here, https://www.adwaterandstir.com/instructions-14/ , keep in mind this is for my specific version. Like many of the other kits, the longest part of this kit is soldering all the LEDs and resistors onto the board. There are a few ribbon cables that go into place, and you are set. Be slightly careful when putting the switches in, they can be a tighter fit into the holes which is great for stability, but they are at the center of the board and it can flex. Once you get it all in the case and screwed down, clearance is a bit low, so make sure the board is ready to go in, when you put it in.

The one part of the setup that is a bit scary, the system comes with a SD card reader that sits flush with the board; if you want it to be accessible from the back of the case you need to bend the 4 legs on it. I used my trusty Radioshack wire stripper/pliers for that!

Software

I connected over USB, the kit also supports Bluetooth on Windows, to get the serial line out and console in. The system supports loading a bunch of programs that are included. The creators website, https://www.adwaterandstir.com/operation/ includes a bunch of guides on things to do. I loaded up CP/M and for fun, of course Zork!

A easy kit to put together, and a fun little project. I now am amassing a wall of these projects, and will have to get a new shelf for this one. Then I will just wonder where Chris found 256mb micro SD cards!

Building a PDP-11 Kit (PiDP-11)

A few years ago I put together a kit from Oscar from http://obsolescence.wixsite.com/obsolescence. It started with soldering, went through setting up a Raspberry Pi image to emulate a PDP-8, and ended with a functioning simulated PDP-8 with working front panel! I was having some issues with one of the integrated circuits; but Oscar, being a great guy, sent me another one and I was able to prove to myself I wasn’t crazy and everything worked. Enjoying the project a lot, I was excited to see he has started production of a PDP-11 kit, this time with a nice plastic injection molded case, and compared to my rev 1 PiDP-8, nicer switches. So I had to order one.

I was able to get the kit working within a few hours of starting, I think part of this is Oscar has gotten better at making these kits; with having the board illustrate where parts go, and having a clean layout, it was fairly easy to put together and solder up. Also my poor soldering skills may have gotten a bit sharper.

While I was at it, I thought I would get my brother a kit so he could get into soldering, which he hasn’t done much of. In going through the instructions I found them a bit light for a novice. To remedy this, I took a bunch of photos during the process and will post them below. The official instructions have more details so I intend just to be additive to those with additional hints, details, and photos.

To start, 30 diodes must be soldered to the board, followed by a few resistors. The tan ones are the 1K ones and go in between some diodes on the bottom row, these spots are labeled “1K”. The 390 ohm resistors go in their labeled spot in the middle of the board. These are put through the board, soldered in, then their legs are cut. Polarity doesn’t matter for these.

Now the GPIO connector for the Raspberry Pi can be soldered in THE BACK of the board, making sure its flat. Followed by the chip socket that goes on the front, in the middle-ish near the rotary encoders. Don’t solder this in with the integrated circuit in it. Note my board is a newer one with some expansion options that Oscars site doesn’t show, make sure to use the correct chip socket location.

Later photo with chip socket and chip installed

This step is the longest and a bit tedious, you need to get 64 LEDs, each with a little riser, and stick it into the board with the correct polarity. That is long leg matching the icon to on the board, for me it was to the left.

Soldered LEDs with board indicator

Now there is a piece of board that comes with the kit, that can sit over all the LEDs to line them up, and once they are all in straight and aligned, they can be soldered in. I would recommend not snipping the legs off until you have tested and are sure they all work. The last soldering steps are to solder the rotary encoders in. After that put the integrated circuit in the socket, and test it out!

Oscar has a bunch on how to test the board so I will leave that to him. One note I will add, my Raspberry Pi had to be a good amount in the socket before it would work well, but this led to the RJ45 port hitting some of the LED contacts and shorting a row. I found getting the anti-static bag the Pi came in, and placing it between the top side of the Pi and the board solved all these problems.

Jumping ahead, I want to mention putting the switches in since this is the one other part of the kit that is a bit confusing and may give people issues. Using the switch lining up tool, that is included with the kit, I found the easiest way to hold everything in place and solder was suggested by Neil over at the PiDP-11 Google group, https://groups.google.com/forum/#!topic/pidp-11/E-RMRVQ15NQ%5B1-25%5D

Neil’s way to hold switches in place

Using this technique, I was able to solder the switches in easily and without difficulty. Follow what the tool says and you should be good. Make sure you are in a well lit room, since in the dark the red and purple can be a bit hard to distinguish.

Using this technique, I was able to solder the switches in easily and without difficulty. Follow what the tool says and you should be good. Make sure you are in a well lit room, since in the dark the red and purple can be a bit hard to distinguish.

Finishing up, consists of more testing with the Pi installed; then going and screwing it all into the case. Be careful, these don’t need to be screwed in very tightly and you can fairly easily crack the acrylic (this I have learned from other projects in the past).

This was a fun kit, and I hope Oscar keeps making more of them. If you have any issues head on over to the PiDP-11 Google Group, and if my guide helped out out, please let me know in a comment below. 🙂

Building a PDP-8 Kit

A bit ago I picked up a PDP-8 replica kit, the PiDP-8. A kit can be picked up here http://obsolescence.wixsite.com/obsolescence/pidp-8-get-one . They are under $200, and I always found older computers interesting so I thought I would give it a shot. I also find The Digital Equipment Corporation and interesting tale of a far gone computing era. (There were t-shirts with the DEC logo on Amazon, but they are gone now)

IMG_4855.JPG

The kit itself is a little smaller than the original control panel; photo from the creators blog above. This is not a real PDP-8, it is a front panel with a Raspberry Pi on the back of it. The Raspberry Pi has an image that is on the user forums (which are incredibly helpful as well as a nice community) which boots very quickly and dives right into the modified emulator. The design is wonderful and just uses the pinout on the Pi.

I got the kit, then ended up moving across the country and did not setup the kit for several months. When I got to building the kit (2015 version, pictured above) it was 2016 and instructions were up for both version. Not many differences except the switches, and how they are mounted. My version needed me to remove pins from each switch then mount each on a rod to keep them aligned. The 2016 version also has more authentic looking switches. I got the switch rod put together with no difficulties.

Then it was down to soldering the trillions, well it felt that way, LEDS to the PCB that came on the kit. Small soldering is not my favorite thing, so this took a bit; but in the end it was done and I was happy with it.

I wanted to test my soldering skills, or lack there of. I plugged the Pi in, and started the image. A few of the lights dimly came up, the rest of them just were dead. Darn this means somewhere it’s broken. I did some traces with a multi-meter, and couldn’t find the fault. Then I realized while it was plugged in the one integrated circuit that handles the LEDs were was getting very hot. I emailed Oscar who made the project and he quickly responded and said it sounded like the integrated circuit was dead and he would mail one the next day or so.

He was extremely helpful and kind, and I got the new chip a few days later. I had to go to Radioshack, (I was surprised I could find one! And its no longer there a few months later) to get a desoldering wick. I haven’t used this before, but it helped me remove the old chip. I soldered the new chip in, and powered it up. Instantly it all came online! I wanted to check all the LEDs, to verify if the OS was keeping some off, or if the circuit was bad, I got a diagnostic program that was written for this system. It did indeed show there was a error, and after resolding a small point then everything was working!

Now that the system works, and I sized it in the box; it was time to paint the switches! I covered half of them with painters tape and painted some brown. Then later did another coat. Then did the white ones so they were not off white or having the red dots on them.

After it dried, I cut a hole in the side of the case so that I could access the USB ports of the Pi. I just had a tiny hobby hack saw and a drill, these were not the best tools to cut the hole but it worked out. I also put electrical tape over the edges of the hole to cover up my handiwork. Then I mounted the PCB with wooden blocks for support into the box. I got some velcro with tape on the back so attach the front panel; that way I can remove it whenever I want for service and easily reattach it.

I got a power switch that is inline with a USB cable. That way I can have a switch to power on and off the device. Then I thought the blinky lights were neat, so I mounted it on my wall for now. It boots directly into OS/8 and in idling does a little light show.

20160525_150912714_ios

The project came out well, and I am excited for Oscar to release his PDP-11 clone he has been working on in the background. I haven’t spent that much time programming it, but it is nice to have a piece of computer history above my desk. A big part of this project has been the awesome community over at the forum https://groups.google.com/forum/#!forum/pidp-8 and the kindness of the project owner and his willingness to help. Oscar’s blog has some cool stuff as well, http://obsolescenceguaranteed.blogspot.com/ .

Next I want to do an Altair 8800 kit, while I wait for the PDP11 version! https://www.altairduino.com.

Update: The Altair-Duino! Altair 8800 Kit