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!
[Atif] is quite fond of his custom Oscilloclock Model 1, originally supplied with a bright green Brimar SE5F/P31 CRT. He just loves its crisp, clear trace! But wouldn’t it be great if he could plug-and-play a different CRT, to suit his mood of the day?
[Atif]’s Oscilloclock Model 1 SE5F with P31 green phosphor… Could we change the mood?
More specifically, could I create a second display unit (the acrylic tube on the left) using a CRT with a soft, long-persistence blue trace? And could he just swap the units around at will, without having to make any changes to the control unit?
Absolutely! But to make the 2nd unit completely compatible for plug-and-play, we’d need the same SE5F type CRT, with a different phosphor. Looking at Brimar’s catalogue, this CRT was available in several phosphors – including a P7 blue. This is the same as used in the original Prototype, and it’s really good at showing off those exotic trailing effects!
So the hunt began…
Now, this particular P7 CRT is famously difficult to come by – whether new OR used.
The most common piece of old equipment employing the SE5F was the ubiquitous Telequipment S51 oscilloscope, but the overwhelming majority of those had a P31 phosphor CRT installed. Indeed, of all the demonstrably working S51’s posted on eBay in the past decade, I have never seen a single one showing an obviously blue trace!
After many months of scouring auctions, suppliers and CRT fanatic colleagues across the globe, I managed to locate one SE5F/P7 in highly questionable condition – and located in Italy! With Google Translate as my friend, negotiations ensued, and – taking a substantial risk that the CRT would actually function – the unit was duly purchased and shipped.
A dirty, slightly rusty SE5F/P7 CRT – snatched from the brinks of destruction in Italy
Often, well-used CRTs exhibit scratches, spots, or burn-in marks on the internal phosphor coating. Fortunately, this CRT’s phosphor proved unblemished! And powering it up (for the first time in decades, most likely), it proved to be electrically faultless, as well!
It works!
Beautifying the Brimar
You may think that cleaning a CRT is hardly worth writing home (or the world) about.
Eucalyptus oil is amazing
But this specimen was slathered in sticky, gooey tape residue, which had to be carefully removed. My chemical of choice for this is, believe it or not, eucalyptus oil! Not only does it remove the gunk, but it also serves to clear up any nasal or bronchial congestion that the technician may have at the time. Two birds with one stone!
The more difficult issue was removal of the graphite coating. During manufacture, the front-most 8 cm of the glass of each SE5F was sprayed with a conductive graphite-based paint. Why? To make a high-voltage capacitor with the spiral accelerator anode (the beautiful green stripes) and similar graphite coating on the inside of the glass. By connecting the external coating to ground, the thrifty circuit designer could avoid using a separate (and expensive) high-voltage filter capacitor in the anode power supply!
External and internal graphite coatings form an effective high-voltage capacitor!
Why remove this coating? Because during use, it gets scratched and marred, as the above photo shows. Such a messy CRT could never be worthy to mount in a clear cast-acrylic case for an Oscilloclock! In addition, the coating obscures some of the attractive spiral accelerator anode, and blocks the incredible view of the trace from behind. And regarding circuit design, we at Oscilloclock NEVER scrimp – the Power Board has oodles of filtering capacity without relying on a graphite coating!
While eucalyptus oil is also effective, it can get rather expensive in the quantity required – especially as the Oscilloclock lab is not conveniently located in Australia! The more reasonably priced chemical of choice here is nail polish remover. As always, there is a side-benefit – the nasal passages are assuaged by a delicate floral scent during cleaning, and fingers have an arguably nice smell that lingers for quite a while!
Joking aside – gloves, open windows, good ventilation, and safety glasses (in case the CRT implodes) are key ingredients for this process!
Eucalyptus oil and nail polish remover has done wonders to this Italian-sourced beauty!
Onward!
Having found the perfect CRT, [Atif]’s plug & play unit is now well under construction.
Epilogue – “Good things come in threes”
It’s not good just getting one CRT. What if [Atif] wanted a spare? What if I wanted a spare for my venerable Prototype clock? Following from the Italian success, I continued a further 6-month hunt, and managed two achievements.
The first was a Telequipment S51b unit located in the U.K. that was non-functional, but that I suspected may have a P7 phosphor installed. How could I possibly suspect this? Well, perhaps this is an art rather than a science, but there were several tell-tale signs:
The way the phosphor looked under the camera flash or ambient light
The colour (or absence) of the graticule (the plastic cover in front of the CRT)
The fact that I got a double when I rolled the dice to decide whether to take the plunge or not!
Oops, it was a P31 – the dice did not roll in my favour that time!
The seller of this unit was not willing (or perhaps not technically able) to extract the CRT, check the CRT type, or ship overseas. Fortunately, my colleague in the U.K. was more than happy to receive the scope at his end. Thus arranged, when the unit arrived he extracted the CRT and confirmed that – sadly – I had purchased a P31 CRT.
But I shipped it across anyway, and the CRT tested well. Rescuing a functional SE5F/P31 from eventual demise was still a worthy accomplishment!
The second achievement was prompted by an auction listing for a “Brimar SE5F”, but with little indication as to the phosphor. The photos of the label (see right), even with subsequent close-ups provided by the seller upon request, were not conclusive.
The image shows two characters beginning with ‘P’. It looks like “P1”, which is another extremely common green phosphor used in many CRTs since the beginning of time. However, we saw in the catalogue earlier that Brimar only supplied GV, P7, P31, and P39 phosphors as standard. It is unlikely that any equipment manufacturer would have requested Brimar to produce a custom CRT batch using the less-exotic P1 phosphor… Leaving the P7 as the only likely candidate!
Convinced, the CRT was duly shipped across and tested – and lo and behold, success! A spare P7 was safely procured.
And with that, the long saga of this CRT hunt closes. As they say, “good things come in threes!”
Like what you see?
Cathode ray tubes used to be manufactured in all shapes, sizes, and colours. Some prove harder than others to find! But if you prefer an exotic creation, don’t give up – there is something for you out there, and here at Oscilloclock we will find it.
As always, see previous posts and the Gallery for info on unique creations!
