When tubes were king, you could go to a drugstore with a box full of them from your TV. There would be a tester that would tell you what tubes were bad and, of course, you could buy the replacements for them. That kind of tube tester was pretty simple. If you wanted to really know how to design with a tube or test its parameters, you were much better off with a curve tracer like the Tektronix 570 that [tomtektest] shows off in two recent videos that you can see below.
That piece of kit fell into [Tom’s] lap thanks to an observant delivery driver. The 1955 instrument is very similar to a semiconductor curve tracer but, of course, has the ability to provide much higher voltage for the tubes. The basic idea is that the X axis sweeps from a few volts up to 100s of volts. The vertical scale will show the plate, screen, or grid current. From those curves you can learn a lot about the characteristics of the tube.
Continue reading “Tubes Have Character With A Tek 570”
If you want to do something you’ve never done before, there are two broadly-defined ways of approaching it: either you learn everything you can about it and try to do it right the first time, or you get in there and get your hands dirty, and work out the details along the way. There’s a lot to be said for living life by the seat of your pants. Just ask anyone who found inspiration in the 11th hour of a deadline, simply because they had no other choice.
Ted Yapo didn’t have a lot of high-speed design knowledge when he set out to build an open-source multi-GHz sampling oscilloscope, but he didn’t let that stop him. Fast forward a year or so, and Ted’s ready to build his third prototype armed with all the hands-on practical knowledge he’s gained from building the first two.
At the 2019 Hackaday Superconference, Ted gave a talk about his journey into the high-stakes world of high-speed design. It’s an inspiring talk, and Ted gives a good look into everything he’s learned in trying to build a sampling ‘scope. We think you’ll appreciate not only Ted’s work, but also the ease with which he explains it all.
Continue reading “Recreating Fast Oscilloscopes Is A Slow Process”
It’s that time of year again, and the Christmas hacks are flooding in thick and fast. To get into the Christmas spirit, the FoxGuard team wanted a custom ornament to hang from the tree. They may have gotten more than they bargained for.
It’s a simple build that demonstrates the basic techniques of working with DACs and scopes in a charming holiday fashion. A Tektronix T932A analog oscilloscope is pressed into service as a display, by operating in XY mode. A Teensy 3.5 was then chosen for its onboard digital to analog converters, and used to output signals to draw a Christmas tree and star on the screen.
Old-school coders will appreciate the effort taken to plot the graphics out on graph paper. While the hack doesn’t do anything cutting edge or wild, it’s impressive how quick and easy this is thanks to modern development methods. While the technology to do this has existed for decades, a hacker in 1998 would have spent hours breadboarding a PIC microcontroller with DACs, let alone the coding required. We’ve come a long way.
It’s a bit of fun, but we highly recommend you don’t try and hang an analog scope off your tree at home. These WiFi-controlled ornaments are perhaps more suitable. Video after the break. Continue reading “Incredibly Heavy Ornament Likely Inappropriate To Hang On Tree”
The Tektronix 2000 series of oscilloscopes are a mainstay for any electronics lab. They work, they’re relatively cheap, they’re good, and they’re available in just about any surplus electronics store. [Mr.RC-Cam] has been hoarding one of these for twenty years, and like any classic piece of equipment, it needs a little refurbishment every now and again. Now, it’s time. Here’s how you repair one of the best values in analog oscilloscopes.
This repair adventure began when the scope died. There were no lights, no screen trace, and a brief hiss sound when it was powered on. (Ten points if you can guess what that hiss sound was!) Armed with a schematic, [Mr.RC-Cam] dove in and pulled the power supply, being careful to discharge the CRT beforehand.
There were no bulging capacitors, no obviously overheated components, and just a little bit of dust. The only solution was to look at the parts with a meter one at a time. Removing the big caps provided access to a row of diodes, which revealed the culprit: a single shorted diode. This part was ordered, and a few other housekeeping tasks were taken care of. The lithium battery on the processor board responsible for storing the calibration constants was replaced, and the new, smaller, caps got lovely 3D printed mounting flange adapters. Now, this old ‘scope works, and we’ve got a lovely story to tell around the electronic campfire.
It seems like holiday decorations come up earlier and earlier every year. You might not have room for a full-blown tree in your lab, but if you have an arbitrary waveform generator and a scope, Tektronix has a way for you to show your spirit electronically.
You can see the video below. Naturally, it features Tektronix gear, but we are pretty sure you could make it work with any arbitrary waveform generator that has at least two channels and a scope with an XY mode.
Continue reading “A Christmas Tree For Your Lab”
We’ve got two hands, so it’s natural to want to use both of them while diagnosing a circuit with an oscilloscope. Trouble is, keeping both hands on the probes makes it a touch difficult to manipulate the scope. If only there were some way to put your idle lower appendages to work.
This multipurpose oscilloscope footswitch interface makes so much sense that we wonder why such a thing isn’t standard equipment on more scopes. [Paul Roukema]’s interface relies on the USB Test and Measurement Class (USBTMC) protocol that allows most modern scopes to be remotely controlled, somewhat like the General Purpose Interface Bus (GPIB) protocol of old. [Paul]’s interface uses an STM32 microcontroller to talk USBTMC to either Keysight’s Infinium scopes or the Tektronix DPO line, since those were what he had to test against. Tapping the footswitch cycles the acquisition mode on and off or triggers a single acquisition. He’s thoughtfully included the USBTMC specs in his GitHub project, so adapting it to other scopes should be straightforward. We’d even wager that older scopes with GPIB could enjoy the same handsfree control.
Have a down-market scope but still want to go handsfree? [Jenny List]’s primer on running a Rigol with Python might offer some hints on where to start.
Here at Hackaday, we’re suckers for vintage instruments. More than one of our staffers has a bench adorned with devices spanning many decades, and there’s nothing more we like reading about that excursions into the more interesting or unusual examples. So when a Tweet comes our way talking about a very special oscilloscope, of course we have to take a look! The Tektronix 519 from 1962 has a 1GHz bandwidth, and [Timothy Koeth] has two of them in his collection. His description may be a year or two old, but this is the kind of device for which the up-to-the-minute doesn’t matter.
A modern 1GHz oscilloscope is hardly cheap, but is substantially a higher-speed version of the run-of-the-mill ‘scope you probably have on your bench. Its 1962 equivalent comes from a time when GHz broadband amplifiers for an oscilloscope input were the stuff of science fiction. The 519 takes the novel approach of eschewing amplification or signal conditioning and taking the input directly to the CRT deflection plates. It thus has a highly unusual 125Ω input impedance, and its feed passes through a coiled coaxial delay line to give the trigger circuits time to do their job before going into the CRT and then emerging from it for termination. It thus has a fixed deflection in volts per centimeter rather than millivolts, and each instrument has the calibration of its CRT embossed upon its bezel.
The 519 would not have been a cheap instrument in 1962, and it is no accident that there are reports of many of them coming back to Tek for service with radioactive contamination from their use in Government projects. We can’t help wondering whether the Russian equivalent super-high-speed ‘scope used the same approach, though we suspect we’ll never know.
If vintage Tek is your thing, have a look at their PCB manufacture from the 1960s.
Thanks [Luke Weston] for the tip.