Some time ago, [javadesigner] asked something that no doubt many of you have been wondering: Do Oscilloclocks emit radiation?
Had a question about oscilloscopes – specifically cathode-ray tubes (CRTs). X-rays etc were discovered in similar tubes, and I’ve read that high kV tubes produce both beta and X-ray radiation.
… Have you ever measured x-ray emissivity with CRTs, and if so, are there any mitigation strategies – especially for X-rays? Leaded glass enclosures, etc.?
Great question!
Will your faithful Oscilloclock do this to you? CRT used in this demo: 130BFB31
Fortunately the answer is a clear NO. Our hand-crafted Oscilloclocks do not emit dangerous radiation.
The general rule of thumb with CRTs (in fact, any electrical equipment operated in a vacuum) is that X-ray emission is negligible at anode voltages less than around 10kV. The accelerated electron beam simple does not have enough energy to generate X-rays when striking the phosphor screen.
But above 10kV, X-rays can and are produced as a result of the higher-energy bombardment. The high-voltage CRTs used in television and computer monitors of the day always incorporated lead glass (strontium-barium glass), to block these X-rays. (And… to protect against implosion!)
In any case, all Oscilloclocks operate at voltages well below 10kV, so this does not become an issue.
Just a few of our CRTs in stock – and none of them emit X-rays!
Thats right – whether we craft your custom timepiece from a behemoth 6498 (at left, operating at 6 kilovolts), a delightful D4P (3kV), a sleek 3WP1 (1.5kV), a cute 50SB1 (1kV) or an eentsy-weentsy CV2302 (500V), you’ll be illuminated but never irradiated.
Fascinated by electron beams and phosphor bombardment? Do you have a question that everyone else wants to ask? Query away, we love Q&A!
These beautiful vintage British* CRTs have travelled the world over the last half century. And like homing pigeons, they have found their way at last to the Oscilloclock Lab!
Here, each piece of glorious glassware will receive the attention they have craved for years. They will be cleaned, rejuvenated, and start their latter-day lives performing retro electronic miracles for loving new owners from all over the world. * In fact, one of these CRTs was not made by a British manufacturer. Can you spot which?
From Unloved to Loved
This SE4DP31 is brand new, complete with protective paper sticker that was attached at the factory to protect the front glass. It’s never been loved. Such a waste, and we will certainly rectify that, as we have done previously for similar CRTs:
Unloved…Doubly loved!
Two is better than One
These bad boys are dual-beam CRTs. They have two electron guns and two sets of deflection plates, meaning they can display two completely independent figures at the same time.
Valvo E10-12GPGEC DHM9-11
We used one of these in the custom Aftershock Clock, to overlay standard clock faces against a map hewn entirely from Lissajous figures. The intensity (brightness) and positioning of each beam can be independently adjusted to get the overlay effect just right!
But importantly – the innards look so cool!
Feeling Blue?
We’ve talked before about rare blue phosphor finds. The newly landed Brimar SE5F/P7 will one day boast both presence and persistence:
Presence. A strong physicality, tempered by a dappled blue light ambiencePersistence. A visual expression of impactful new, awash with memories and traces of old
With thanks…
We dedicate this post and the promise of seeing these CRTs reincarnated to [Atif]. Many thanks for helping these pigeons find their roost!
Are you in a state of cathode-ray rapture? Check out other CRT related posts, and see the Gallery to see examples of vintage glassware objects given new leases on life!
Today’s story began with a mail from [Eric], who’d read up on the Oscilloclock 3-inch VGA Assembly and wondered if it could be used to create an old-school serial terminaldisplay on a vintage oscilloscope CRT.
Yes it could! In fact, the Oscilloclock Lab did one better. Instead of just a VGA display controlled by an external device, we developed native terminal firmware that accepts DEC VT52 compatible commands over a serial port, and renders all text and graphics using beautiful, curvy Lissajous figures.
The stuff of dreams. The OscilloTerm Exo B7S4.
Demonstrating basic terminal features, connecting to a PC via serial cable Oh, did I mention? It’s a clock as well!
Zork, anyone?
Ultimately, [Eric] just wanted to play Zork. And together we made it happen.
The CRT. The Case.
[Eric] wanted a sleek ‘skeleton’ look. His choice of a gorgeous B7S4 CRT, mounted in custom-machined cast acrylic supports, exposes all glassware and allows for a titillating rear viewing experience.
And with a high-transparency cast acrylic case housing the electronics, the OscilloTerm Exo can be enjoyed from every angle!
Astute readers may wonder about the 2.1 kilovolts of high voltage coursing through their innocent-looking device. Rest assured! All internal wiring is sealed off, and Oscilloclock CRT harnesses are hand-crafted with heavy insulation and precautions taken against dust, prying fingers, rats, and even salivating cats.
Safety in action! Mil-spec connector (left); custom-designed acrylic cap on the CRT connector (right) An O-ring blocks dust from entering the CRT/socket gap (picture from the Oscilloblock)
This case and CRT mounting variation is branded the Oscilloclock Exo, and has proven its wow-factor at several public exhibits to date. We certainly love it, and [Eric] did too!
The Terminal.
This post would never be complete without showing you what real serial terminals from the 1970’s looked like, and explaining what they actually did! Here goes…
Terminals such as the above were physical input/output console devices, back when computers were the size of massive refrigerators, and the operator would sit remotely – at a desk in a separate area, or even a different room.
The terminal and the remote computer were connected via a cable, and would communicate each other by sending data back and forth across the cable; mainly terminal commands and ascii encoded text. Most commonly, a serial communication protocol was used to get the data safely from one end to the other – and hence the devices were known as serial terminals or even serial consoles.
Amusingly, they were also called dumb terminals, because they had no computing power of their own; they were only extensions of the computer to which they were connected.
The OscilloTerm Terminal.
[Eric] wanted a special Oscilloclock that he could also operate as a terminal, connecting it to a remote computer via cable. The remote computer would control the display, using the same serial protocol and commands as an ancient dumb terminal.
But an Oscilloclock is anything but dumb. [Eric] wanted to keep all the standard exciting screens and features of his Oscilloclock active, and only display the special Terminal screen when the remote computer started to send commands. Then, when the commands stopped, the Oscilloclock should go back to the screen it was on!
His wish was our command! Here’s a demo of smart screen switching in the final product:
Some technical Comments
Naturally, the terminal emulator firmware was written entirely in assembly language.
PIC18F2680 – the Oscilloclock workhorse.
We use assembly mainly because the minimalist PIC microcontroller used in the current Control Board revision has only 64K ROM, and an unbelievable 3328 bytes (yes, BYTES!) of RAM. To squeeze all the lovely Oscilloclock features in, while driving Circle Graphics real-time processing, the code and memory space has to be clean, tight, and heavily optimized at the machine code level.
Assembly. It’s the ONLY way to squeeze it all in!
For even more technical details, such as the list of VT52 (and VT100) commands supported by the OscilloTerm, and the various configuration parameters that can be tweaked to make the terminal emulator more ‘friendly’ when connecting to a specific device, check out the Support page. Worth a visit!
Why Zork? And HOW?
Zork is an interactive adventure game. But it’s old. And it’s text-based, because it was run on computers long before fancy graphics capabilities were widely available. The player explores mysterious locations, solves puzzles, and collects treasures while avoiding various hazards and creatures. All by reading text and typing commands and responses!
[Eric] was able to play Zork by loading the game’s Z-code into a Z-machine interpreter known as Frotz, on a PC connected to the OscilloTerm. But there was trickery involved!
He had to recompile a version of dfrotz (the dumb terminal version of frotz) to remove the status bar and audio from the game.
He needed to wrap the dfrotz output with a custom Python script to support the OscilloTerm’s 16×8 screen and simulate the required baud rate.
But now that’s done, he can play anyInfocom game that runs in dfrotz on his OscilloTerm!
What’s next?
Readers would probably agree that adding a generative AI feature would be incredibly cool. For example, the War Games feature is great, but the text on the screens is all pre-programmed. What if you could interact more naturally with your Oscilloclock?
Another one for the list!
Are you a serial serial terminal collector? Do you want to play Zork on the oddest device imaginable? Or, you fancy a clock in the Oscilloclock Exo range? Contact us and let us know!
Q: “What’s your New Year’s Resolution? A: “Why, 1024 x 768, of course!”
Geeky jokes aside, here at the Oscilloclock lab we DO have a form of New Year’s resolution! 「日進月歩」Nisshin-geppo, which loosely translates as “Steady progress day by day“, reflects the goal to complete the the once-in-a-decade re-design work, and resume crafting beautiful Oscilloclock products. It also highlights confidence that issues currently facing the wider world will be overcome, one step at a time.
In keeping with local traditions, [Oscilloboy] wrote the slogan in Japanese calligraphy. But there, tradition ended and true joy began! Behold, courtesy of an Oscilloclock VGA Core assembly, Oscilloclock’s 2021 New Year’s resolution on a beautiful old 7-inch oscilloscope!
The Setup
After choosing an appropriately meaningful four-character phrase for our resolution, I asked [Oscilloboy] to write out the characters. Bucking with tradition, we used standard white A4 paper instead of calligraphy paper. The ink took more time to dry, but we wanted to maximize the contrast.
[Oscilloboy] demonstrates his prowess in Japanese calligraphy. Right: the finished product!
After scanning the handwritten characters and inverting the images, I created a rolling video in 1024 x 768 resolution. (See? The joke at the beginning of the post about resolution was serious, after all!)
I then played this through an Oscilloclock VGA Core assembly, which is essentially a graphics card that allows you to use a beautiful old CRT as a rudimentary computer display. (For earlier write-ups, see VGA display… On a 3″ scope tube! and The VGA Cube! .
The assembly used here features a late prototype of the Revision 3 Power Board, which I have been working on for almost a year. I won’t go into all the bells & whistles yet. Stay tuned!
A VGA Core assembly – displays monochrome images from VGA, SVGA and XGA inputs
Unlike a permanent Oscilloclock conversion (see the Gallery for examples), this was only a temporary setup. The VGA Core was positioned externally, with the harness routed into the 7VP1(F) CRT via the rear of one of the side panels. No invasive procedures needed!
Just LOOK at that beautiful CRT socket – brown Bakelite!
No VGA socket on your ultramodern slim notebook of choice? No problem – use an off-the-shelf HDMI to VGA converter!
And voila – the final result! Japanese calligraphy on a vintage 7″ oscilloscope!
About the Model – A rare 1963 Nitsuki Oscilloscope
Nitsuki is the brand name of Japan Communication Equipment Co., Ltd., a specialist in television and microwave broadcasting systems. The firm’s English name was originally Nihon Tsushinki Co., Ltd., so you can see how the Nitsuki moniker came about.
Check out this exquisite cap on the pilot lamp!
By 1963, the Japan domestic test equipment market was mature and quite competitive. English language labeling had become stock-standard. This scope is one of very few units I have ever obtained that has Japanese labeling. How appropriate for today’s display!
Japanese labeling – a rarity!
Some of the higher-quality oscilloscopes of this era featured flip-latches and detachable side panels, for easy access. See the Toshiba ST-1248D for another example. These scopes are infinitely more enjoyable to work with and show off than scopes with a slide-out chassis.
This model is also quite unusual for its time in that most of the components are located under the chassis! The valves (tubes, if you prefer) are even mounted horizontally. Nitsuki used very robust construction techniques, including very tidy cable lacing.
In fact, their design was so robust that the scope functions almost perfectly today (except for some triggering instability), yet there is no evidence of major repairs in the last 57 years!
Back to its natural self – a nice old 7-inch 1963 oscilloscope!
Like what you see?
The Oscilloclock lab struggled in 2020 due to worldly events, but NOW – day by day, step by step, the newly designed Oscilloclock boards are at last taking shape! Does your New Year’s ‘resolution’ for your next project specify 1024 x 768? Or perhaps you’re into displaying fancy calligraphy on vintage CRTs? Let me know.
And as always, see previous posts and the Gallery for info on other unique creations!
Critical Update 25 December 2021
Well. Christmas Day 2021, and [Oscillowife] — the chief editor, advisor and critic extraordinaire — just informed me that I had placed [Oscilloboy]’s first character「日」upside down when creating this post! Apologies to our readers for the gross oversight.
It’s been 12 months! But better late than never to eat humble pie…
For those cat lovers out there, let me present one beautiful kitten who knows his place in life: bedded down amongst some beautiful Brimar CRTs!
This picture, submitted by an Oscilloclock aficionado, proves that there ARE others with an intense passion for CRTs out there. And this group now includes the feline species!
Anyone out there have a capacity-controlled canine? An electron-excitable echidna? Or a filly with a phosphor fetish? Let me know!
