Reverse Engineering Teaches An Old Scope New Tricks

[PMercier] clearly loves his old Tektronix TDS3014 scope, which did however lack essentially modern connectivity such as an Ethernet port for control and a USB port for a convenient way to capture screenshots. So he decided to do some in-depth reverse engineering and design his own expansion card for it. The scope already has an expansion port and an expansion card, but given this model was first released in 1998, purchasing an OEM part was not going to be an option.

They don’t make ’em like they used to. Test equipment is today is built to last a decade — but usually lives on much longer. This is certainly true for the previous generations of kit. It’s no surprise that for most of us, hand-me-downs from universities, shrewd eBay purchasing, and even fruitful dumpster dives are a very viable way to attain useful and relevant test equipment. Now, while these acquisitions are more than adequate for the needs of a hobbyist lab, they are admittedly outdated and more to the point, inaccessible from a connectivity and communication standpoint. A modern lab has a very high degree of automated data acquisition and control over ethernet. Capturing screen dumps on a USB is a standard feature. These modern luxuries don’t exist on aging equipment conceived in the age of floppy disks and GPIB.

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Digital Oscilloscope Does Its Best Analog Impression

Do you ever find yourself yearning for the days before digital storage oscilloscopes (DSOs)? Where even the basic scopes commanded four figures, and came in a bench-dominating form factor? No, of course you don’t. The DSO is a wonder of modern technology: for a couple hundred bucks you can have capabilities that previously would have been outside the reach of hobbyists, all in a package that’s small enough to fit on even the most cramped workbenches.

Which is why the good folks of the EEVblog forums are so confused about the OWON AS101, a modern digital oscilloscope that’s designed to look and operate like the analog CRT monsters of old. Despite the 3.7 inch LCD, users are treated to the classic analog scope look, and the switches and knobs on the front should trigger a wave of nostalgia for hackers of a certain age.

But this isn’t just some “retro” look-alike, OWON is committed to delivering on that analog experience by taking away all those modern digital features we’ve become so dependant on. This single-channel scope can’t save data to USB, doesn’t have any sort of protocol decoding capabilities, and forget about automatic…well, anything. It’s even limited to 20 MHz, just like the old-school CRT scopes that you pick up for a song at any swap meet. All for the low, low, price of $150 USD from the usual importers.

In the EEVblog thread, the best idea anyone can come up with is that the OWON AS101 is designed for educational markets in developing countries, where outdated equipment is so common that there may actually be a need for faux-analog oscilloscopes to match what’s already in use. These new-manufactured “analog” trainers can be used to get students ready to a professional life of using antiquated technology. It’s hard to believe, but sometimes we can forget how fortunate many of us are to have easy access to cheap tools and equipment.

Even still, when you can get a pocket-sized 10 MHz DSO for around $50, it’s difficult to imagine how this analog-digital hybrid could possibly attract any takers at 3x times the price. If any of our readers would care to shed some light on this unusual piece of gear, we’d love to hear it.

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Oscilloscope Mod For The Blues

Roughly 8% of males and 0.6% of females are red-green color blind, and yet many common oscilloscopes use yellow and green for the traces for their two-channel readouts. Since [Roberto Barrios] is afflicted by deuteranopia, a specific form of red-green colorblindness that makes differentiating between yellow and green hard, if not impossible, he got to work hacking his Agilent oscilloscope to make it more colorblind friendly.

Starting with a tip from [Mike] from the EEVblog forums, [Roberto Barrios] set out to rewire the LCD interface and swap the red and green signals. That way yellow will turn bluish (red component replaced by blue) and it could be seen as “very different now” from the green trace on the readouts. Sounds simple right? Well, slight issue: the 0.5 mm pitch of the connector. He did not want to design a PCB and wait a few weeks to receive it, so he decided on using 0.1 mm wires held together with Kapton tape to route each signal individually from one connector to the other. After an hour under the microscope, it was done. And boy, his work is impressive, go check it out.

Voila! It worked splendidly. Now [Roberto Barrios] can use his scope. And, the stock UI is mostly grey or white, so swapping the red and blue channels did not change much the appearance of the interface. Moreover, the switch had a small unintentional bonus, the loading screen is much cooler now with an edgy red sky. Further, [Roberto Barrios] “would not be [himself] if [he] could resist changing the CH1 button backlight LED to blue, to match the new trace color. So, no [he] couldn’t.”

This was a well done and very functional oscilloscope mod, but if you need more frivolity in your life, fear not: we’ve got your back with real-time Quake played on an oscilloscope.