Tag Archives: 時計

Oscilloclock Bare(ly) makes it to Brazil

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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.

Wires, wires…. What goes where?

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!

Connect !!

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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!

Quake News!

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Fake news – a common keyword these days. Fortunately, Oscilloclocks do not display fake news. But wouldn’t it be handy to see quake news on an exotic scope clock? This is the challenge [Atif] gave me – and one year and many grey hairs later, here is the result: The AfterShock Clock!

This custom-crafted Oscilloclock Core Duo assembly is a unique first in several ways:

  1. It’s the first scope clock ever that pulls in and displays real earthquake data!
  2. It’s the first scope clock ever that puts a dual-beam CRT to good use – one beam for the clock display, and the other for the earthquake and map overlay!

Earthquake display

The AfterShock Clock’s WiFi module connects at regular intervals to two public APIs (servers) to collect the latest earthquake events. It then feeds earthquakes to the clock’s quake gun controller, rotating quakes every 30 seconds. Cool!

(Note: flickering is due to camera effects and is not visible to the human eye)

Of course, there is the usual wide variety of standard clock screens to cycle through! The quake map’s beam is automatically dimmed for most of the screens, giving a soft ‘watermark’ effect.

Dual-beam CRT

The E10-12GH CRT used in this clock is certainly not mundane!

Beautiful spiral PDA lets you really see inside the cavity!

Nothing beats a dual-gun CRT for intricacy… (except a quad- or pentuple-gun CRT!)

Oscilloclock Core Duo

Atif wanted to create his own case, so he initially asked for an Oscilloclock Core. But currently a single Core set does not provide control, deflection, and blanking circuits to drive TWO electron guns… So he had two choices:

  1. Wait an eternity for me to redesign the boards to fully support dual beams.
  2. Get started now! Simply put two Core assemblies together, with some degree of inter-control and removing any redundant circuits.

Atif chose the latter – and the Oscilloclock Core Duo was born!

WiFi setup

Setting up the WiFi connection is easy – just connect a device to the clock’s administration SSID and pull up the admin page. (To foil any would-be hackers out there, the admin SSID is available only for the first 5 minutes after power is applied.)

Then, access the admin URL and configure the connection to your home router:

There are a million other advanced settings to tweak things such as quake polling interval, quake magnitude filters, maximum quake age before purge, and other geeky aspects….

Oh, I forgot to mention – the clock also synchronizes time against an NTP server, eliminating the need for a GPS module.

Like what you see?

Do you go for electron guns? idolize intricate electrode assemblies? Have a filament fetish? Or just want some quake news? This kind of clock might fit the bill. Let me know!

The Oscilloclock Core

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Over the years, folks out there have reached out to me with all sorts of crazy ideas about cases and housings for scope clocks and custom CRT displays. Here are some interesting examples:

  • The console of a vintage pipe organ
  • An ancient grandfather clock
  • A cylindrical case made of some exotic wood
  • A “cathedral” style vintage radio

Essentially, these people wanted just the innards of an Oscilloclock, which they would build into their own case. Could I help out?

Absolutely! For people who want to roll their own cases, and who have experience handling high voltage electronics and CRTs, I occasionally prepare custom board sets that are lovingly hand-assembled, tested, and tweaked for optimum performance with a given CRT. Here we go:

The Oscilloclock Core

Oscilloclock Core, hand-crafted in 2015 for a discerning customer in Germany

An Oscilloclock Core, hand-crafted in 2015 for a discerning customer in Germany


The standard Oscilloclock Core layout, on a test acrylic mounting

The standard Oscilloclock Core layout, on a test acrylic mounting

I supplied this particular unit with an 8SJ42J Chinese-made CRT, just for testing purposes. This is a 3″ PDA tube with a highly restrictive rectangular viewing area, but the customer found it just great for checking things out!

Oscilloclock Core - complete set for 8SJ42J - 03Oscilloclock Core - complete set for 8SJ42J - 06
Oscilloclock Core - complete set for 8SJ42J - 02

What comes with it?

Here’s what’s comprises the typical Oscilloclock Core:

  • 1 x Fully assembled and programmed Control Board (optional on-board GPS)
  • 1 x Fully assembled Deflection Board (latest ultra-linear revision)
  • 1 x Fully assembled Power Board optimised for a given CRT (latest revision with options: onboard high-bandwidth blanking amplifier, rotation coil supply, auto fan speed control, unblanking plate modulation, and isolated bright/dim input)
  • 1 x Fully assembled CRT Board (optional; an external blanking amplifier recommended when the CRT cable is longer than 50cm)
  • 1 x Rotary encoder
  • 1 x Worldwide 9V power supply (high quality wall wort unit, commercial ratings)
  • 1 x Garmin GPS unit with 5m cable; wired to board-side connector (not required for onboard GPS)
  • 1 x Set of standard inter-board and CRT harnesses for testing and reference (10kV/3kV silicone melt-proof used for HV cables, other LV cabling also heat-resistant)
  • 1 x Cast acrylic test mounting assembly, fitted with the boards, ready for testing out-of-the-box with your CRT
  • 1 x Ceramic adjustment screwdriver
  • Service documentation (schematics, board layouts, complete Digikey BOMs, harness specs)
  • All components are latest available types sourced within the last 6 months, 0.1% or 1% tolerance resistors, minimum 2 x rated working voltage capacitors, all lovingly hand-mounted by myself
  • All boards sprayed with HV lacquer for moisture and arcing protection
  • 2-week satisfaction guarantee. But no long-term warranty on board-only purchases

Naturally, the lengths of all harnesses and inter-board cabling can be customized according to the owner’s requirements. And there is also an Oscilloclock Core Cube arrangement, where the boards are stacked to reduce the length and width of the overall unit.

What CRTs does it support?

The Power Board and Deflection Board are increasingly flexible with each revision, but I insist on performing all configuration of the Core here in my lab. This allows me to tweak for maximum performance, and provide a proper satisfaction guarantee.

Typically I work with the owner to recommend a CRT based on preferences such as size, colour, and aesthetics. However in cases where the owner already has a CRT in mind, and I don’t have the particular CRT or a close equivalent, I ask the owner to send me one to test against. Or, I simply procure one; after all, one can never have too many CRTs!  (Though my better half does not agree…)

The current Oscilloclock Core board revisions meet the following operating parameters:

  • Maximum cathode to deflection voltage of 2175V
  • Maximum accelerator voltage of 3525V for PDA type CRTs
  • 6.3V heater, max 0.7A
  • Support for “Deflection Blanking” CRTs (see treatise here)
  • CRT rotation coil supply (+/-5V)
  • Precision deflection amplifier capable of driving +/- 275V with 0.1% linearity

Like what you see?

Check out the Availability page for more information, and of course see the Gallery for some unique CRT creations – many with an Oscilloclock Core at their heart!

Toshiba Transformed

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I believe in reincarnation. Every vintage device sporting a CRT deserves to live again, to be loved again, to lift someone’s spirits again. And in 2014, this beautiful Toshiba ST-1248D received its chance, born again as a suave Oscilloclock!

Toshiba ST-1248D Oscilloclock

See this in HD, and find more exciting videos on my YouTube channel

Manufactured sometime in the mid to late 1950’s, the ST-1248D was extremely well-designed and assembled, compared to other compact models available on the domestic Japanese market at that time. The engineers considered both function and form – latched panels on the side and back, delicately laced wiring, and a relatively spacious interior conducive to heat removal and circuit reliability. But the delightful brass bezel is what really makes this one of the most beautiful Oscilloclock conversions ever.

Toshiba ST-1248D - Brass bezel

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Luxury 2013 edition Model 1-S!

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This 2013 edition hand-crafted scope clock exudes sophistication and elegance, to match the most refined interior – be it the boardroom or the bedroom. The 1-S boasts solid brass fittings custom-turned in Japan, ultra-transparent cast acrylic housings, and a decadent harness with chrome connectors and gold-plated pins from France. The brand-new old stock CRT was selected especially for its gentle white-blue trace and extremely long persistence, to provide a relaxing and refreshing viewing experience.

2013 luxury edition Model 1-S scope clock from Oscilloclock.com

This particular unit went on display at Maker Faire Tokyo 2013, and was sold within several hours. Enquire via the Contact page for pricing and availability of the Model 1-S and other exclusive Oscilloclocks.


See more related videos on my YouTube channel

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Oscilloclock at Maker Faire Tokyo!

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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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BOO!

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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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