It’s official: Oscilloclock is on Hiatus!

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Recent worldly events have taken a huge toll on the crafts and maker community globally. Sadly, the Oscilloclock Lab has not been immune.

It is with a heavy heart that I announce that Oscilloclock will be on official hiatus until further notice, at very least until the end of 2022. We won’t be accepting any further orders or enquiries, but any repair work for existing Oscilloclock patrons will continue to be handled with great passion and gusto.

This was a painful decision to make, but we are battling a perfect storm: extreme parts shortages, high shipping costs and long delays, a suddenly weakened yen (we are Japan-based), and an immediate need for your devoted cathode-ray engineer to focus on his day job and skills training as he reorganizes to go “back to office”.

I’m hopeful that in the coming 6-12 months, many of these factors will go back to ‘normal’, and we can formally resume our beloved cathode-ray activities! Stay subscribed to the site for future updates.

All the best from the entire Oscillofamily!

Oscilloclock Bare(ly) makes it to Brazil

Whether directly or indirectly, the pandemic seems to have slowed everything down: chip production; the global economy; and even Oscilloclock blog post publishing!

But perhaps most impacted of all is transport logistics. [Dante] in Brazil discovered this to his dismay in July 2020, when he purchased an Oscilloclock Bare unit. The P.O. had stopped all air service to Brazil just 3 weeks earlier – well after our discussions had started. Oh no!

[Dante]’s crisp new Oscilloclock Bare, ready to go, but unable to ship!

[Dante] waited patiently for 6 months for the post office to resume accepting airmail service to Brazil. But they never did. And FedEx and DHL came at too hefty a price. In desperation, he authorized shipment by sea – and at last, in December 2020, his package was off!

Absence (of air mail service) makes the heart grow fonder...

After an agonizingly long wait, [Dante] finally received his unit 6 months later – in July 2021. He then spent the next 5 months completing his dream project!

[Dante]’s Dream: A Hewlett Packard retrofit

The Oscilloclock Bare is designed to be a no-frills controller assembly that highly knowledgeable folks can install into their own displays. [Dante]’s dream was to use this to convert his beloved HP 182T / HP 8755C unit into a living, breathing scope clock.

And convert he did!

Question: How do you add ambience to a home?
Answer: Instill new life into a device from yesteryear!

Clearly, [Dante]’s 18 month end-to-end was worth the wait.

The Build

[Dante] was kind enough to supply a write-up of his project, including some clever solutions for pitfalls along the way. Let’s hear from him in (mostly) his own words!


Motivation

The model HP 182T is an oscilloscope featuring a large CRT with a graticule of 8 x 10 major divisions and a display area of 133 cm2, coated with a P39 aluminized phosphor for high brightness and long persistence.

The HP 182T works as a display mainframe supporting other HP plug-in test equipment, such as the HP 8755C, a swept amplitude analyzer.

Both items are nowadays considered “vintage” test equipment. But with the Oscilloclock board installed, they have been transformed into a unique appliance with a natural appeal for practical use. Far better than the regular surplus market destinations, or — even worse — destructive disposal!

HP 182T + HP 8755C. Can you spot the Oscilloclock control board?
Control board installed!

HP 8755C in short

This plug-in unit works primarily as a signal conditioner and a multiplexer for “almost dc levels” from three RF detector probes attached to three input independent channels. There are front panel adjustments for the scaling, gain and multiplexing controls that provide the appropriate Y-Axis composite signal for displaying by the HP 182T mainframe.

The Oscilloclock control board was elected to be installed inside this plug-in unit.

HP 182T in short

This oscilloscope is built around the CRT with its high voltage power supply.

The X-Axis signal from the Oscilloclock board is fed to the HP 182T’s chain of the horizontal pre-amp plus output amplifier, which drives the CRT horizontal deflection plates.

The internal wiring of the HP 182T connects the CRT’s vertical deflection plates directly to the plug-in cabinet of the display mainframe, so the Y-Axis signal from the Oscilloclock board is routed inside the HP 8755C itself.

The Z-Axis signal from the Oscilloclock board is fed to the HP 182T’s gate amplifier.

Drawbacks

Contrary to any standard X-Y scope where the two input channels are always supposed to have electrically similar (if not identical) characteristics, the correct operation of the Oscilloclock board for the application here was shown to be not as seamless as first imagined. You have to face some details of these integrated “host” equipment (HP 182T + HP 8755C) to see why…

As described, there are distinct amplification chains accepting the Oscilloclock output signals. This presents specific challenges regarding (a) the differential gain for the X and Y signals, and (b) the differential time delay between any combination of the three X, Y, and Z signal outputs of the Oscilloclock board.

First Approach

Before having the board at hand and expecting to make it work as soon it arrived (the shipping took longer than expected due to COVID restrictions), I first planned the signal flow and did the wiring. I had one eye on achieving a ‘clean packaging’ of the board inside the HP 8755C, and the other on ensuring compatibility between the Oscilloclock’s X-Y-Z output signals and their respective chains planned in the host equipment, considering signal amplitude and required frequency response.

The adaptations made at this time considered a minimally-invasive approach, where the criteria was to “make it simple”. This was limited to just opening or re-using connections and keeping the existing routing, in order to use the Oscilloclock’s X-Y-Z output signals in the most simplistic way possible.

Another necessary one-time adaptation was for the board’s power supply, and integration of its PSON output signal with the equipment’s hardware. This part of the design was successfully kept to the end of the project without any further modification.

First time installation of the oscilloclock board

Upon arrival and a bench test of the Oscilloclock board with a scope, I immediately figured out that the amplitude levels for the X and Y output signals were lower than expected (maybe due to my misinterpretation of the specs). I did the gain compensation corrections again and went thru the complete installation of the board inside the host equipment, anxious to see it working.

What a disappointment when instead, up came a completely distorted and elliptically shaped image, blurred with noise, and what looked like un-blanked retrace lines. Worse yet, mainly when alphabetic characters were displayed on the screen, none of the shapes were correctly formed.

Of course, that was time for a break — and a complete review of the job and the work done so far!

Chasing the problems

The Lissajous figures generated by the Oscilloclock board use an approximately 40 KHz  sinusoidal signal, so I started to play with an external generator at the same frequency and amplitude for the X and Y signals (at about 1 Vpp) and trace it inside the HP 8755C and HP 182T.

At this time, I’d already exercised the Z-axis waveform from the Oscilloclock board and the expected processing through the HP 182T. There was no evidence of problems with this Z-axis signal chain, and I achieved a measured propagation delay of around 50 nS.

The minimalist approach mentioned earlier showed its consequences, when a propagation delay of an impressive 8 uS was measured at the vertical deflection plates, and  around 1.5 uS at the horizontal deflection plates! It was time again for another break, to elaborate a new routing scheme for the X and Y signals.

Final Approach

From the previous analysis, I ended up with two different and both very large propagation delays for each of the X and Y signals (as compared with the measured 50 nS for the Z-axis). How to solve this? It did not seem to be only a routing problem.

I decided to investigate X-Y-Z signal propagation delays in the two units separately. After a thorough measurement of propagation delays inside the HP 182T itself, comparing with the HP 8755C plug-in itself (where the Oscilloclock board was installed), I concluded on two countermeasures:

1. The complete removal of the Processor board XA-6 from the HP 8755C. (This is where the Y-axis signal from the Oscilloclock board had initially been connected.) Instead, this routing was transferred directly into the Normalizer Interface board XA-11 (which interfaces with the HP 182T).

2. Also at the Normalizer Interface board XA-11 inside the HP 8755C, the substitution of two original op amps U9A and U9B (HP #1826-0092) by TL072 op amps, which are faster and have a higher slew rate.

These solutions were enough to align the signal propagation and complete my project!

Dante JS Conti, 8 November 2021

Like what you see?

We do! We love to hear back from Oscilloclock owners, to hear their stories.

Check out our previous posts and the Gallery for info on other unique creations!

New Year’s Resolution!

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「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…

New design on the way?

Well, I think that’s what’s going on….

In a desperate attempt to save his blog from becoming the all too familiar not-updated-in-5-years dead blog, the senior technician has resorted to seeking help from one of his sons, previously referred to as the 1st junior technician. Although my knowledge on CRTs and electronics is close to none compared to that of the senior technician, I will give you some updates on the recent activities of the main man himself, who I am sure all of you are eagerly awaiting the return of.

Amid the COVID-19 crisis, the senior technician has been lucky enough to be able to work at home. You would think that without his everyday commute of two hours, he would be more relaxed and able to spend more time with his family members. However, he is instead spending excessive time in front of the computer. At first, I speculated that he was having a rough time with his work. Or was he? Under closer examination, I realized that the additional time spent on the PC was actually something related to Oscilloclock. Something about a brand new design: “once-in-a-decade refresh,” and some such. Not really sure how significant this is to you all, but judging from the look on his face when he emerges from his room for dinner, it must be something BIG!

Another clue that the Oscilloclock Lab is heavily active is the vast array of international deliveries to our home in the past half year. Shipments from countries that you’ve never heard of, in all shapes and sizes, arriving so frequently that I can’t help feeling for the poor postman who has to carry these heavy objects up to our door. I must tell you, there is nothing worse than hearing the bell ring and rushing down to the door anticipating your own Amazon delivery of a new pair of shoes, and instead seeing a massive box from Montenegro containing who-knows-what-type-of-CRT.

The master craftsman’s work could very well be hindered by the noise from his two highly energised teenagers, [Oscillokid] and [Oscilloboy]. So how does he maintain concentration? The secret is a well-positioned cave. His workshop is intentionally situated at the very edge of the house. He simply closes the lone door to the shop, to avoid hearing a dinner-call or a request for more screen time from his Oscillosons. Until, of course, the commander-in-chief of the household raises her voice!

So there it is, a brief update on what’s going on and how the senior technician’s doing. Rest assured that he is working very hard on his projects, and has not in the least swayed from his passion; indeed, he is more immersed than ever. He will no doubt inform all of you anxious readers of his magnificent projects once they are ready for exposure. Until then, thanks for reading, and stay safe!

A Cathode-ray Cat

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!

Cathode-ray Cat

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!

Brimar Beauties for Plug & Play

[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!

Brimar supplied the SE5F in several standard phosphors – including the highly desirable P7

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.

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!

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.

Oops, it was a P31 – the dice did not roll in my favour that time!

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!

Screens & Things

Recently I had an enquiry from [Frank], who had just begun a life-long love affair with scope clocks by purchasing one on eBay. The clock was great – but he felt that the two available screens (simple analogue and digital clock faces) lacked a certain oomph.

He then stumbled across Oscilloclock.com, and in his smitten state immediately reached out with his number one question: just what screens are available on an Oscilloclock?

Well, let me save Frank’s time trawling through years of blog posts. Right here in one place are most of the Oscilloclock screens and features created to date.

Enjoy the show!

Standard Time Screens

These stock-standard analogue and digital time screens may be quite simple, but they do evoke the ‘retro’ look that most people appreciate.

And you can flip a menu setting to display days, months, years in Japanese:

There are also some ‘random’ screens that add in a bit of dynamic visual entertainment:

  • Random number screen
  • Random letter sequence screen
  • Random four letter word screen (clean words only, by default!)
  • Random phrase screen (the phrase list is typically customized to a theme)

And of course the mesmerizing Timedrops screen:

Themed Screens and Features

… These themed features were developed more recently, and can be added for a small fee to help cover development costs!

Astroclock (Sidereal Time)

External XY input

OscilloTerm (serial terminal)

Oscilloblock (lego)

Metropolis

Aftershock Clock (Earthquake display)

Unbirthday Clock

War Games

Logo screens

Over the years many folks have requested that I render custom logos in Circle Graphics. Here are some examples:

“Seasonal Treats”

Up next are some fun, mildly interactive animation features. Not exactly screens per se, these animations pop up after a predefined period of inactivity – but only during certain months of the year. Can you guess which months?

Boo!
Santa in your Clock!

Menu screens

There are far too many configuration menu and test screens to present here. Fiddle to your heart’s content!



Q. How are screens switched?

Screens are switched simply by rotating the control knob in one direction or other.

There is also a configurable auto-switch feature; the screen is changed every 90 seconds in a predefined order (with the exception of some animation screens). The display time is configurable, and the auto-switch feature can also be turned off for those who prefer to switch screens manually.

Q. How are screens selected & configured?

Customers can request screens to include and/or specify the switching order. The configuration is done here in the lab before clocks are delivered.

Oscilloclock also provides a firmware upgrade kit, which allows the customer to upload a revised version of the firmware into the clock themselves. Using this, updates to screens and other features can be uploaded without shipping the clock back to the lab.

Q. What is the process for rendering a custom screen or logo?

We typically prepare a mock-up based on the customer’s description, sketch, or image file. This is tweaked as needed until the screen looks just right to the customer.



Like what you see? Contact me!

Connect !!

These days, just about everyone has an old oscilloscope lying around. You know, an old, dusty, derelict scope handed down from Grandpa (or Grandma). Well, [Paul] had something even better – an old Tektronix 602 X-Y Monitor! Could an Oscilloclock Control Board drive this vintage beauty? Absolutely. Could I make an aesthetically pleasing case? Definitely. How about time sync via WiFi? Stock standard!

Presenting the Oscilloclock Connect:

Here’s what it looks like plugged in to my fabulous old Tektronix 620 monitor:

And why not have a pair of Connects drive a Tek 601 and 602?

The Build

The main component of the Connect is, of course, a standard Oscilloclock Control Board. As usual, all 121 parts on Paul’s board were individually mounted and soldered by hand. The board then was programmed and underwent rigorous inspection and testing. Finally, the board was cleaned to remove flux and renegade flecks of solder, and sprayed with HV coating for humidity protection and – arguably more importantly – to give it its glorious sheen.

The case was custom-made and professionally machined right here in Japan from 6mm-thick sheets of pure cast acrylic (not extruded). This is an extremely transparent, hard, high grade acrylic – and Oscilloclocks deserve nothing less!

The case was sprayed with a special acrylic cleaner and static protection solution, before fitting the various components. Naturally, every part was cherry-picked, right down to the three BNC connectors – they needed an aesthetically pleasing colour, but they also had to have a shaft long enough to mount through 6mm-thick acrylic!

Finally, the physical interface! The knob was chosen for its perfect finger-fit and delicate aluminium/black tones, which gently contrast with the rest of the unit.

The Compatibility Crisis

Over the years, many folks have observed that the scope at hand has an “X-Y mode”, and asked if they could just ‘plug in’ an Oscilloclock Control Board. “Is it compatible?” Unfortunately, the response has usually been disappointing.

You see, creating figures and characters with Circle Graphics relies on the scope’s ability to turn the beam on and off at split-second intervals. This feature is called a “Z-axis input”. While many scopes from the 80’s and beyond do sport such an input, there are two common limitations:

Limitation 1: AC-coupled Z-axis inputs

Capacitive coupling – effective at isolating the input from cathode potential (-1260V !)

The input is connected to the CRT’s grid or cathode circuit via a capacitor. This is a low-cost, effective way to isolate the (usually) very high negative voltage of the grid circuit from the input.

The problem here is that the capacitor, by its very nature, removes the edges from the pulse. The controller is no longer able to control the beam on/off timing, and you end up with uneven blanking across the segments, as shown in the screenshot at right.

Depending on the values of the capacitor and the surrounding resistors, the symptoms may not be severe. However, the best way to resolve this problem (while still keeping the oscilloscope’s original circuit intact) is to insert an isolated DC blanking amplifier directly in series with the grid (or cathode). See the Kikusui 537 Oscilloclock for an example of this.

LIMITATION 2: INSUFFICIENT BLANKING AMPLIFICATION

Most oscilloscopes tend to require at least +5V on the Z-axis input to noticeably blank the beam. The Connect, however, is only capable of delivering +2.5V. It works just fine if you set the scope’s Intensity control very low, but as you increase intensity, the blanking quickly becomes ineffective.

Below we have a beautiful Japanese YEW (Yokogawa Electric Works) 3667 storage scope. The left shot is misleading due to the camera exposure; the displayed image is actually extremely dim. The right shot shows the same* image with the intensity control increased – the image is bright, but there is no blanking!

* Astute readers will observe that the time is significantly different between the two shots. This is a result of the WiFi NTP sync kicking in right in the middle! More (or less) astute readers may also notice that the scope’s trace rotation is not adjusted very well…

Of course, it would be a simple matter to incorporate a pre-amplifier for the Z-axis, which would solve this problem. This will be introduced with the next Control Board revision!


Like what you see?

Nothing brings more joy than connecting this bundle of usefulness into a woefully unused old oscilloscope or X-Y monitor. If this is of interest to you, visit the Availability page for more information, and of course see the Gallery for other unique creations!

From the Archives – Vintage Transmitting Tube Art

Diverging from CRTs only briefly but holding steadfast to the warm, soft glow of valves, here I introduce a piece of Valve Art crafted long before Oscilloclock came into existence!

I spotted this vintage 1967 ultrasonic cleaner unit at the local Ham Fair, and it was love at first sight. Originally with a steel cabinet with peeling paint, the unit wasn’t much to look at on the outside. But after applying a copper coat to the chassis and fitting a sleek acrylic cabinet, this device simply dazzles!

 

Featuring not one, but two of these stunning Hitachi 3T12 transmitting valves!

Who needs a heater in winter, when you can have one of these power-hungry devices?

I bet this lovely triode, with its zirconium-plated anode and thorium-tungsten filament, really impressed the original owner of this ultrasonic cleaner…

 

These aesthetic innards simply ooze awesomeness. It’s as if they actually designed this for the art museum!

Made in 1967, but boasting an incredible 200W output – absolutely deadly !


Sadly, my workshop no longer had room for this historic showpiece, so with a heavy heart, I recently powered it down for the last time. However it will go to a loving new home…

Long live vintage ultrasonic cleaners!

War Games on an Oscilloclock!

As I’ve hinted before, your friendly Oscilloclock gang is entirely pacifistic. We abhor the thought of actual military activity in this modern day and age. BUT we love games just as much as anyone – and we also love light-hearted movies with happy endings!

So when [Ian] (of Bunker Club Clock fame) came up with the idea of a feature based on the iconic 1984 flick “War Games“, I pounced on the chance!

Check out my YouTube channel to see this and other videos in HD!

Now, this may look like a simple animation. But Ian’s Oscilloclock is powered by a tiny processor with minimal specifications, and 100% of the code is written in assembly language. Implementing this baby in assembly and keeping within just 3K of RAM was quite an accomplishment!!

About the host clock

The gorgeous model shown here is a painstakingly-retrofitted Heathkit CO-1015 Engine Analyzer. It’s the perfect play-toy for any serious motor-head who grew up during the Cold War!

First up on the custom build list is the original meter fitted with amber LED lighting and ticking audibly each second. (And yes, the tick intensity can be easily adjusted.)

Next up, there is the optional External X-Y input feature. Normally, this is used for plain and simple Lissajous figures like the below…

… but by tweaking some settings, we can get some segments of Jerobeam Fenderson’s incredible Oscilloscope Music Kickstarter video to display quite nicely!

Peeking inside the Engine Analyzer Oscilloclock is also a must-do! Not only is this visually appealing, but you also get a significant olfactory kick from the sweet smell of vintage electronic components…

Attractive Oscilloclock boards and cabling, neatly tucked away

The original circuit is completely bypassed – but still looks awesome!

Tech Talk – Strategies, Maps, and Missiles

The War Games feature uses the Oscilloclock’s Sprite Engine module to display the world map and up to 9 missiles when the W.O.P.R. system is simulating various war strategies.

32 of the 130+ strategies seen in the movie are implemented. For each strategy, a random number of missiles are launched along a predefined Primary trajectory, followed by a random number of missiles along a predefined Retaliatory trajectory. If any of the 9 missiles remain, they are launched along randomly selected (but predefined) trajectories.

Trajectories are predefined because computing them using 8-bit arithmetic would consume a huge number of cycles! At least, a small amount of randomness is added to the launch position and velocity parameters at run-time, to make things more interesting.

As the simulation progresses through the strategies, the speed of the launches increases and the delay between launches decreases. This gives a similar effect to that in the move, where WOPR moves through strategies at warp speed until it realises that there is no winning this game…

A Joint Effort

Creating a huge number of realistic trajectories (68 in total), translating start and end X and Y coordinates from latitude and longitude into the Oscilloclock’s Cartesian plane was a task of mind-blowing proportions! Here we see our 2nd junior technician eagerly earning his room and board.


Like what you see?

Are you a petrol-head? You need an Engine Analyzer ticking over at your bedside or in your office! Were you brought up during the Cold War, perhaps in the Soviet Union or in the US? Get the War Games feature and fry the world safely! Contact me if you like what you see.

(Disclaimer: Oscilloclock.com hopes that no-one is offended by the deliberately light-hearted tone of this post, in referring to the decidedly serious topic of nuclear warfare.)