Powering On A 1985 Photophone CP220 Videoconference System

January 6, 2026 by No comments

The concept of remote video calls has been worked on since Bell’s phone company began pitching upgrading from telegrams to real-time voice calls. It wasn’t until the era of digital video and real-time video compression that commercial solutions became feasible, with the 1985 Image Data Corporation Photophone CP220 being an early example. The CP220 is also exceedingly rare due to costing around $25,000 USD when adjusted to inflation. This makes the teardown and repair on the [SpaceTime Junction] channel a rather unique experience.

Perhaps the coolest part of the device is that the manual is integrated into the firmware, allowing you to browse through it on the monochrome CRT. Unfortunately after working fine for a while the device released the magic smoke, courtesy of the usual Rifa capacitors doing their thing. This is why a full teardown was necessary, resulting in the PSU being dug out and having said capacitors swapped.

After this deal the device powered on again, happily accepting a video input and saving screenshots to the floppy drive before it was replaced with a FDD emulator running FlashFloppy firmware. Unfortunately no video call was attempted, probably because of the missing camera and having to set up a suitable POTS landline for the built-in modem. Hopefully we’ll see that in an upcoming video to see what we common folk were missing out on back in the day.

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Illustration of Chladni's technique for producing his figures, from John Tyndall's Sound (1869)

Popular Science Experiments In Sound During The 19th-Century

January 5, 2026 by 9 Comments

Check one, two; check one, two; is this thing on? Over on The Public Domain Review [Lucas Thompson] takes us for a spin through sound, as it was in Britain around and through the 1800s.

The article begins by introducing the Father of Acoustics, German physicist Ernst Chladni. After placing grains of sand on a thin metal plate and drawing a violin bow along one edge Chladni figures appear, making manifest that which previously could only be heard, that is, sound waves.

It’s fun to think that it wasn’t so long ago that the physics of sound was avant-garde. Middle class Victorian society was encouraged to reproduce cutting edge experiments with equipment in their own homes, participating in a popular science which was at the same time part entertainment and part instruction, for young and old alike. Throughout the rest of his article [Lucas] lists a number of popular science books from the period and talks a little about what was to be found within.

See the video below the break for a demonstration of Chladni figures from The Royal Institution. Of course the present state of the art regarding sonics is well advanced as compared with that of the 19th century. If you’re interested to know more check out Building A Wall-Mounted Sound Visualizer and Seeing Sound For Under $200.

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Scientific staff members working on the computing machine Setun

The Setun Was A Ternary Computer From The USSR In 1958

January 3, 2026 by 44 Comments

[Codeolences] tells us about the FORBIDDEN Soviet Computer That Defied Binary Logic. The Setun, the world’s first ternary computer, was developed at Moscow State University in 1958. Its troubled and short-lived history is covered in the video. The machine itself uses “trits” (ternary digits) instead of “bits” (binary digits).

When your digits have three discrete values there are a multiplicity of ways of assigning meaning to each state, and the Setun uses a system known as balanced ternary where each digit can be either -1, 0, or 1 and otherwise uses a place-value system in the normal way.

An interesting factoid that comes up in the video is that base-3 (also known as radix-3) is the maximally efficient way to represent numbers because three is the closest integer to the natural growth constant, the base of the natural logarithm, e, which is approximately 2.718 ≈ 3.

If you’re interested to know more about ternary computing check out There Are 10 Kinds Of Computers In The World and Building The First Ternary Microprocessor.

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Twelve Days Of Christmas As Performed By 1980s Speech Chip

December 25, 2025 by 5 Comments

In a curious historical twist, the “Twelve days of Christmas” are actually the days of revelry that followed the 25th. The preceding period, Advent, was traditionally a fast, not unlike Lent. When and why a fast became an excuse for chocolate calendars we cannot say, but this historical information is presented to explain that this great hack by [Kevin], making a vintage speech synthesizer chip sing the classic carol will remain relevant at least until January 5th — or perhaps even the 19th, for the Orthodox amongst us.

The chip in question is an SP0256A-AL2, which you may remember from various speech projects for 8-bit computers back in the day. It can talk, after a fashion, by reproducing 56 “allophones” — the sounds that make up English speech — from ROM. Singing, though? We cannot recall much of that back in the day, but then, a talking computer was impressive enough.

As it turns out this is building on an earlier hack [Kevin] did in which he used an Arduino to make the venerable speech chip MIDI controllable. In that project’s write-up it is revealed that a Si5351 programmable clock module is used to give a variable pitch signal to the speech synthesizer. In this way he’s able to get about an octave an a half, which is good enough when the carol in question only spans one octave.

Of course the pitch signal needs to be varied by something and for that the venerable Arduino once again takes the place of an 8-bit computer. In this case it’s pre-programmed, but can also be set up for MIDI control.Of course nothing says you can’t use true retro hardware or a more-capable RP2040 instead of the Amtel chip.

It’s sad to think how much compute power has been wasted this year on AI-generated novelty carols when a little bit of 1980s silicon and some ingenuity can do nearly as good — or better, depending on your tastes. Continue reading “Twelve Days Of Christmas As Performed By 1980s Speech Chip” →

Watch A Recording Lathe From 1958 Cut A Lacquer Master Record

December 13, 2025 by 14 Comments

Most of us are familiar with vinyl LPs, and even with the way in which they are made by stamping a hot puck of polyvinyl chloride (PVC) into a record. But [Technostalgism] takes us all the way back to the beginning, giving us a first-hand look at how a lacquer master is cut by a specialized recording lathe.

An uncut lacquer master is an aluminum base coated with a flawless layer of lacquer. It smells like fresh, drying paint.

Cutting a lacquer master is the intricate process by which lacquer disks, used as the masters for vinyl records, are created. These glossy black masters — still made by a company in Japan — are precision aluminum discs coated with a special lacquer to create a surface that resembles not-quite-cured nail polish and, reportedly, smells like fresh paint.

The cutting process itself remains largely unchanged over the decades, although the whole supporting setup is a bit more modernized than it would have been some seventy years ago. In the video (embedded below), we get a whole tour of the setup and watch a Neumann AM32B Master Stereo Disk Recording Lathe from 1958 cut the single unbroken groove that makes up the side of a record.

The actual cutting tool is a stylus whose movement combines the left and right channels and is heated to achieve the smoothest cuts possible. The result is something that impresses the heck out of [Technostalgism] with its cleanliness, clarity, and quality. Less obvious is the work that goes into arranging the whole thing. Every detail, every band between tracks, is the result of careful planning.

It’s very clear that not only is special equipment needed to cut a disk, but doing so effectively is a display of serious craftsmanship, experience, and skill. If you’re inclined to agree and are hungry for more details, then be sure to check out this DIY record-cutting lathe.
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Converting A 1980s Broadcast Camera To HDMI

December 1, 2025 by 14 Comments

Although it might seem like there was a sudden step change from analog to digital sometime in the late 1900s, it was actually a slow, gradual change from things like record players to iPods or from magnetic tape to hard disk drives. Some of these changes happened slowly within the same piece of hardware, too. Take the Sony DXC-3000A, a broadcast camera from the 1980s. Although it outputs an analog signal, this actually has a discrete pixel CCD sensor capturing video. [Colby] decided to finish the digitization of this camera and converted it to output HDMI instead of the analog signal it was built for.

The analog signals it outputs are those that many of us are familiar with, though: composite video. This was an analog standard that only recently vanished from consumer electronics, and has a bit of a bad reputation that [Colby] thinks is mostly undeserved. But since so many semi-modern things had analog video outputs like these, inspiration was taken from a Wii mod chip that converts these consoles to HDMI. Unfortunately his first trials with one of these had confused colors, but it led him to a related chip which more easily outputted the correct colors. With a new PCB in hand with this chip, a Feather RP2040, and an HDMI port the camera is readily outputting digital video that any modern hardware can receive.

Besides being an interesting build, the project highlights a few other things. First of all, this Sony camera has a complete set of schematics, a manual meant for the end user, and almost complete user serviceability built in by design. In our modern world of planned obsolescence, religious devotion to proprietary software and hardware, and general user-unfriendliness this 1980s design is a breath of fresh air, and perhaps one of the reasons that so many people are converting old analog cameras to digital instead of buying modern equipment.

The box of the Busch Electronic Digital-Technik 2075

The Busch Electronic Digital-Technik 2075 Digital Lab From The 1970s

November 26, 2025 by 6 Comments

In a recent video, [Jason Jacques] demos the Busch Electronic Digital-Technik 2075 which was released in West Germany in the 1970s.

The Digital-Technik 2075 comes with a few components including a battery holder and 9 V battery, a push button, two 1 K resistors, a red LED, a 100 nF ceramic capacitor, a 100 µF electrolytic capacitor, a quad NAND gate IC, and a counter module which includes an IC and a 7-segment display. The kit also comes with wires, plugs, a breadboard, and a tool for extracting modules.

The Digital-Technik 2075 doesn’t use the spring terminals we see in other project labs of the time, such as the Science Fair kits from Radio Shack, and it doesn’t use modular Denshi blocks, such as we saw from the Gakken EX-150, but rather uses wire in conjunction with yellow plastic plugs. This seems to work well enough.

In the video, after showing us how to do switch debouncing, [Jason] runs us through making a counter with the digital components and then getting the counter to reset after it counts to five. This is done using NAND gates. Before he gets stuck into doing a project he takes a close look at the manual (which is in German) including some of the advertisements for other project labs from Busch which were available at the time. As he doesn’t speak German [Jason] prints out an English translation of the manual before working through it.

We’ve heard from [Jason] at Hackaday in recent history when we saw his Microtronic Phoenix Computer System which referenced the 2090 Microtronic Computer System which was also made by Busch.

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