Tek 520A VectorClock!

Television broadcasting has switched from analog to digital – and if you’ve got a nice HD TV, you’ll be loving it!

But with that transition came the death of an entire breed of equipment – the Vectorscope.

Tektronix 1420 Vectorscope

Just to be clear, these are not monitors for playing ancient video games using vector graphics!!  No, the Vectorscope is (was) used to give a delightful view of the ‘vectors’ inside an NTSC or PAL video signal, describing the color components of the signal.

If you were lucky enough to be a TV broadcast technician, you’d use your Vectorscope all the time to check your vectors’ amplitudes and phase. You would even give your vectors names like ‘Jack’ and ‘Jill’, and check up on their relationships daily, just as any responsible guardian would!

But above all, you would marvel every single day at the beautiful hardware you were using, and the complex circuitry involved. Take a look at my Tektronix 526 Vectorscope, which has oodles of delicious tubes to heat my shop on a nice winter’s day:

Tektronix 526 Vectorscope

Well, it all went digital and there is no longer any need for analog color signal analysis. But dry your tears… There is something even better:

Announcing the Tek 520A VectorClock

This lovely Oscilloclock reincarnation of a Tektronix 520A, sold at Maker Faire Tokyo 2013, allows its new owner to forever relive the magic of NTSC, PAL and SECAM analog color.

Tektronix 520A VectorClock - brilliant blend of the old and new!

Tektronix 520A VectorClock – brilliant blend of the old and new!


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The Tektronix 520A has a stunning built-in array of lights for illuminating the CRT graticules. By simply removing the bezel and external graticule, the Tek 520A morphs into a deliciously moody timepiece!

Tek 520A VectorClock - Glorious Glow

Normally, I shun CRTs with built-in graticules. Their lines detract dreadfully from an Oscilloclock image. But here! The Tek 520A’s internal vectorscope graticule is round! What better way to accentuate a Circle Graphics driven display?

Silky smooth Circle Graphics on steroids!

Silky smooth Circle Graphics on steroids!

Under the Cover…

The Tek 520A is solid-state. It can be left on 24 hours a day and not fail for many years. This makes it a perfect match for my Maximum Re-use + Minimum Invasion policy: nearly all existing circuits – HV power supply, deflection amplifiers, blanking – are put to use, with just a few (reversible) tweaks.

Tek 520A VectorClock - Maximum re-use, Minimum invasion

The Oscilloclock Power Board is mounted neatly next to its own dedicated low voltage supply. A small relay board can be seen below, for controlling the Tek’s main power unit. All cabling is HV-tolerant and neatly fastened with high-temperature cable ties.

Tek 520A VectorClock - Control Board mount and cabling

Of the more interesting reversible ‘tweaks’ needed for this retrofit, here we see a delightful little trimpot pretending to be a transistor. Quite an act, I would say!

Tek 520A VectorClock - an unorthodox transistor replacement

Like what you see?

If you love big, looming Vectorscopes and need to have one put to good use in your living room, Contact me. And be sure to subscribe from the front page, to track all the other exotic experiments and unique timepieces targeted for 2014!


Credits to [Quinn] in Canada, for providing the initial inspiration for the Tek 520A VectorClock project!

Santa in your Clock!

The world-renowned Santa Claus. How does he get in your house to deliver presents? Does he go down the chimney (if you have one)? Does he shrink and squeeze under your door? Of course not! What silly ideas.

Santa simply converts himself into pure energy and beams in!! I’ve seen this glorious event myself, and now you can too – with the latest Seasonal Treats enhancement from Oscilloclock.com.

Beam me in, Santa!

Beam me in, Santa!

Not only can you watch Santa on his travels, but you can even control where he drops his presents! Can YOU help him deliver the gifts?

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Oscilloclock at Maker Faire Tokyo!

Summer is over! But even as cool weather sets in, the Oscilloclock.com lab is smoking hot, preparing for…

Maker Faire Tokyo 2013

Visit the Oscilloclock.com booth, and check out the luxury 2013 edition Model 1S – to be announced in this blog at end October. One unit will go on sale at the event!

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Transformer Corner part 4

Winding your own HV Transformer

In Transformer Corner Part 3, I looked at how to choose materials for a custom HV transformer. One way was to pull stuff from the junk-box – I did this in my early Prototype. The much, much better way was to use an off-the-shelf core with documented specs.

Let’s look at winding up the transformer. It’s amazingly easy to get a workable result!
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Transformer Corner part 3

Designing your own HV Transformer

In Transformer Corner Part 2, I looked at the power supply used in my early Prototype, and showed how to determine the key requirements for the HV transformer.

Now, let’s see how I could choose the materials and design the transformer – without any pesky mathematical formulae!

A hand-wound HV transfomer!

The end goal – a hand-wound HV transfomer!

Picking a core

The first challenge was to find a suitable core from my junk box. First off, recall from Part 1 that this couldn’t be iron (too ‘slow’ for 151 kHz), and it couldn’t be air (too ‘weak’ for 25mA). I suppose I could have tried plastic, milk, or even beer – but I knew better. I knew about a substance called Ferrite.

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Transformer Corner part 2

In Transformer Corner part 1, I introduced one of the key parts of the Oscilloclock – the HV transformer, and tried to illustrate some of the concepts and history behind it.

Next, let’s explore the Prototype’s power supply configuration. This will tell us a lot more about the transformer I had to wind!

Power supply design

My greedy little Oscilloclock wanted lots of different voltages…

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BOO!

Oscilloclock.com proudly presents a new feature – Seasonal Treats !

This month, the ghosts come out of the attic and merge with the electron stream, leaving their telltale prints in the phosphor… but if you get too scared? Just push the button and blow them up!

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Transformer Corner

The atmosphere at Oscilloclock.com has been charged lately. Mails have been pouring in from folks who want to generate high voltage for their CRT projects, but have instead ended up with high tension from frustrated attempts. The primary culprit? Lack of a decent HV transformer.

HV Transformer basics

CRTs require high voltage, to coax electrons out of the electron gun and then accelerate them towards their fiery demise at the screen. This voltage can range from hundreds of volts for small tubes, to tens of kilovolts for large tubes! In the case of the Prototype and Model 1 CRTs, around 3kV was needed.

My Oscilloclock needed 3kV to draw this!

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The Invisible … Beam?

One of the most exciting things you can do with a Scope Clock is to simply look at it from behind! In many CRTs, the anode coating (a conductive black surface sprayed onto the inside of the glass) doesn’t extend all the way to the screen – leaving a nice gap of clear glass from which to observe the beautiful electron beam.

Ha – you can put down your magnifying glasses now.

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