Taking Apart a Vintage Oscilloscope

After getting a power supply and a multimeter, the next piece of gear a hacker would want to add to their bench is the oscilloscope. Nowadays, even the cheapest ones cost a few hundred dollars yet pack in the features. At the other end of the scale, if you can pony up close to a  million dollars, you can help yourself to an oscilloscope capable of 100 GHz bandwidth and 240 GS/s sampling rate. With that perspective, it becomes interesting to take a look at this video (embedded below), where [Jack Ganssle] shows us the Philco 7019 Junior Scope which was introduced way back in 1946. It seems the Philco 7019 model was an identical re-badged version of the Waterman Model S-10-A PocketScope.

[Jack] is familiar to all of us as an embedded systems engineer, but in this video he does a teardown of this vintage analog model. He starts off by walking us through the various controls, of which there are not a lot, in this “portable” instrument. At around the 3:40 mark in the video, he’ll make you wince as he uses a screwdriver and hammer combo to smash another ’40’s vintage CRT just so he can show us it’s innards — the electron beam source and the horizontal and vertical deflection plates. The circuit is about as bare-bones as it can get. Besides the CRT, there are just three vacuum tubes. One is the rectifier for the power supply, a second one is used for the vertical amplifier while the third one is the free running horizontal sweep oscillator. There is no triggering option — you just adjust the sweep frequency via a potentiometer as best you can. It does have internal, external and line frequency function selection, but it still requires manual adjustment of the sweep oscillator. There’s no blanking signal either, so the return sweep is always clearly visible. This is evident from the horizontal burn mark on the phosphor of the CRT after decades of use. It’s amusing to see that the vertical position could be adjusted by moving a magnet attached to the side cover.

The Oscilloscope Museum website hosts the Instruction Manual for this model, as well as a sales brochure which makes for very interesting reading after viewing [Jack]’s video.

Thanks, [Itay], for the tip.

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Ask Hackaday: Are Unlockable Features Good for the User?

There are numerous examples of hardware which has latent features waiting to be unlocked by software. Most recently, we saw a Casio calculator which has the same features as its bigger sibling hidden within the firmware, only to be exposed by a buffer overflow bug (or the lead from a pencil if you prefer a hardware hack).

More famously, oscilloscopes have been notorious for having crippled features. The Rigol DS1052E was hugely popular on hacker benches because of it’s very approachable price tag. The model shipped with 50 MHz bandwidth but it was discovered that a simple hack turned it into the DS1102E 100 MHz scope. Tektronix has gotten in on this action as well, shipping modules like I2C, CAN, and LIN analyzation on the scope but requiring a hardware key to unlock (these were discovered to have a horribly insecure unlock method). Similar feature barriers are found on Rigol’s new reigning entry-level scope, the DS1054Z, which ships with protocol analyzation modules (among others) that are enabled only for the first 70 hours of scope operation, requiring an additional payment to unlock them. Most scope manufacturers are in on the game, and of course this is not limited to our tools. WiFi routers are another great example of hardware hosting firmware-unlockable features.

So, the question on my mind which I’d like to ask all of the Hackaday community is this: are unlockable features good for us, the people who use these tools? Let’s take a look at some of the background of these practices and then jump into a discussion in the comments.

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Ask Hackaday: Help Me Choose A ‘Scope

If there is one instrument that makes an electronic engineer’s bench, it is the oscilloscope. The ability to track voltages in the time domain and measure their period and amplitude is one akin to a light in the darkness, it turns a mere tinkerer with circuits into one in command of them. Straightforward add-on circuits can transform a basic oscilloscope into a curve tracer, frequency response display, and much more, and modern oscilloscopes offer a dizzying array of useful measurement features unimaginable to engineers only a few years ago. And I need your help to pick a new one.

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Yet Another Inductance Measuring Scheme

How do you measure the value of an unknown inductor? If you have an LCR bridge or meter, you are probably going to use that. If not, there are many different techniques you can use. All of them rely on the same thing my Algebra teacher Mr. Harder used to say back in the 1970’s: you have to use what you know to get what you don’t know.

[Ronald Dekker] must think the same way. He took a 50-ohm signal generator and a scope. He puts the signal output to about 20kHz and adjusts for 1V peak-to-peak on the scope. Then he puts the unknown inductor across the signal and adjusts the frequency (and only the frequency) for an output of 1/2 volt peak-to-peak.

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Little Helper: Open Source Hardware Hacker Multitool

We love a good multitool. There’s something seductive about knowing that if, for some reason, you need to saw down a tree on a moment’s notice, you have a tiny saw in your pocket. We also like electronic versions of the multitool: gadgets that serve a lot of purposes as you develop and debug hardware. One of the most polished-looking ones we’ve seen is [Phillip Schuster’s] Little Helper.

The open source gadget looks like an iPod (if an iPod had header pins sticking out of it). It has basic analog I/O capability, can generate PWM pulses, sniff I2C traffic, and do lots of other features. It is open source, so you can always add more capabilities if you need them.

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Easy and Effective Way to Measure PWM… Without a Scope!

Sometimes when a project is coming together, you need to cobble a tool together to get it completed. Whether it’s something very involved, like building a 3D printer to fabricate custom parts, or something relatively simple, like wiring a lightbulb and a battery together to create a simple continuity checker, we’ve all had to come up with something on the fly. Despite having access to an oscilloscope, [Brian] aka [schoolie] has come up with his own method for measuring PWM period and duty cycle without a scope, just in case there’s ever a PWM emergency!

The system he has come up with is so simple it’s borderline genius. The PWM signal in question is fed through a piezo speaker in parallel with a resistor. The output from the speaker is then sent to an FFT (fast fourier transform) app for Android devices, which produces a picture of a waveform. [schoolie] then opens the picture in MS Paint and uses the coordinates of the cursor and a little arithmetic to compute the period and the duty cycle.

For not using a scope, this method is pretty accurate, and only uses two discrete circuit components (the resistor and the speaker). If you’re ever in a pinch with PWM, this is sure to help, and be a whole lot cheaper than finding an oscilloscope!

How To Get 50 More Zed From Your Rigol DS1054Z

[Chris] has been spending a lot of time in the wife’s sewing room lately, and things got pretty serious late last night as he hacked his shiny new Rigol DS1054Z to unlock the 1104Z capabilities lurking within.

The rumors are true, and ungoverning the software is as simple as looking up your serial number and knowing the right URL for generating a valid license. [Chris] ran into a dud site, but that’s the price of doing business in the shadowy parking garage basements of the interwebs. Once he knocked on the right door and uttered the secret word, however, he became the proud owner of 50MHz additional bandwidth, decoders for SPI, I²C, and RS-232, twice the storage depth, and all teh triggers that ship with the 1104Z.

Stick around for [Chris]’s video walk-through. Can’t rationalize the purchase even at the ridiculously low price point? Here’s one way to make it happen. You’ll laugh, you’ll cry, you’ll learn some French.

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