标签: Tektronix

Here's my oscilloscope: a 1966 15Mhz Tektronix Type 422.   Vintage 1966 15Mhz Tektronix Type 422 When I bought my oscilloscope for twenty dollars, it was dead. Someone had tried to stick ten pounds of fuse into a one-pound fuse holder and subsequently broke the fuse holder. I replaced the fuse holder with a non-standard fuse holder and a fuse of the recommended type and rating, thus returning the instrument to a functioning capacity.   Vintage scope with new fuse holder. Now, the Tektronix Type 422 Oscilloscope is a fine instrument of quality manufacture, but I would like to try some of those new features they've come up with since the moon landing—features like 200MHz bandwidth, 1GS/s, 4 analogue channels, 16 digital channels, automated measurements, and FFT analysis that are provided by the Tektronix MSO2024B digital oscilloscope that is the prize of this contest, so I'm going to tell you this story. One day, I received a message from manufacturing that they had an instrument that was dead and that they required the assistance of my superior technical skills and extensive engineering knowledge acquired through advanced education and years of experience. So, I put on my anti-static smock and my anti-static shoe straps and grabbed my trusty DVM with the very pointy probes and headed down to manufacturing to render said assistance. Upon arriving in manufacturing and being shown the instrument, I asked the manufacturing engineer what was wrong with the device. He replied, "If I knew that, I would not require the assistance of your superior technical skills and extensive engineering knowledge acquired through advanced education and years of experience." So, I asked, "Well what's the problem?" He said, "It's dead." I said, "Well, what did you try?" He said, "I replaced all the boards with known good boards and the power supply with a known good power supply and it is still dead." He spilled the beans. I knew he would crack under my relentless questioning. As I sat down by the instrument, I bumped the table, which caused the screen to blink. So I banged on the table, causing the screen to blink again. I continued to bang on the table making the screen blink much to the amusement of the technicians working behind me. I did not care because I had a nibble and I was going to play it out before I got lost in the labyrinth of the innards of the device.   Handy troubleshooting technique. After several minutes of judicious banging, the screen came up and stayed on. I heard from behind me someone guffaw, "He's got it working," followed by laughter from the peanut gallery. I then took my pen and poked at the cables in the device until I found one that caused the screen to malfunction. I shut down the instrument and removed the cable. Then, using my superior technical skills and extensive engineering knowledge acquired through advanced education and years of experience, and using my trusty DVM with the very pointy probes, I determined that the cable was indeed defective; knowledge of which I imparted on the manufacturing engineer, thus proving the old adage that it is not enough to think outside the box. Sometimes you have to bang on the side. So please kindly consider my submission, though it is as badly stitched together as Frankenstein's monster (if Dr. Frankenstein had used duct tape) and send me that fancy new Tektronix MSO2024B digital oscilloscope that is the prize of this contest. I'm sure it will help in repairing those instruments I cannot fix by banging on the table. This article was submitted by P.C. (name withheld by request) as part of Frankenstein's Fix, a design contest hosted by EE Times (US).  

My dad gave me a Devry scope and VTVM combination for my graduation from 8th grade (in the Catholic school system that's a milestone like finishing middle school). He had assembled the unit a few years earlier as part of a mail-order course in electronics. VTVM stands for "vacuum tube voltmeter," a long defunct phrase that described a high-impedance VOM (volt-ohm meter). The device was about 19" wide and maybe 25" deep with quite a few tubes. There was no case, and it's amazing I never broke the exposed CRT. The scope didn't have a trigger; in that tube era, trigger circuits were expensive, so it, like many others, had a free-running time base one adjusted in an attempt to stabilise the on-screen image. The unit served me well till late high school when I managed to save enough to buy and build a transistorized (though still with CRT as TFT screens were decades away) Heathkit scope. Both of those are long gone, and there have been many more scopes in my life over the years. Favourites include Tektronix's 7000 series of modular scopes. The high-end units we used in the 70s were fantastically expensive, had tiny little push buttons, and for the time offered unbeatable performance. The old Tek 545 I had for a while was a monster. It probably weighed 100 pounds, used vacuum tubes, but just ran forever. No one wanted it when it was time to move on, and I regret having to send it to the dump. For the last 15 years my main instruments have been Agilent units; the MSO-X-3054A that now graces my bench is a fantastic unit they'll have to pry from my cold, dead hands. In recent years some low-cost alternatives have come out. Rigol and others offer what appear to be fairly decent models in the half-a-thousand dollar range and less. Even Tek has some low-end sub-$1k units. I've not played with these but am very impressed with the specs versus cost. A lot of money can be saved by using a PC for the front end, and I've reviewed quite a few of these very inexpensive USB-based devices. Some are scopes; some logic analysers, and some a combination of the two, often with other features as well. The folks at Embedded Artists (a great name for a company) in Sweden sent one of their LabTool products, a scope/logic analyser/protocol sniffer/waveform generator. It isn't boxed; it's just two stacked and exposed boards as in the following picture. The LabTool Logic analyser "probes" (a wiring harness) are supplied, sans clips, but no scope probes. This is all not surprising considering the price: just 99 €, or about $135 at November 2013 exchange rates. That's a fantastic price. This unit is a little different than most of the others I've reviewed. There's no fancy FPGA sucking in data at high rates of speed. Instead, the unit uses a fast LPC4370 MCU, which has a Cortex M4 and a pair of M0s. Digital and analogue data is just sampled by the processor. Here are the specs: * 11 channel logic analyser that can run at up to 100 Msps. * 2 channel oscilloscope that runs to 80Msps with a bandwidth that varies between 3 to 12MHz depending on the channel's gain setting. * The digital and analogue channels can be turned around to generate signals. * It will decode SPI, I 2 C, and UART signals. * The digital zero vs one limit is 3.3V. But you can connect an external voltage source to change it to any value between 2.4 and 5.5V. As with most of these products, the sample rates depend on a number of factors. It can be as low as 20 Msps if both analogue and digital data is being sampled. The 47 page user's manual, downloaded from their web site, is the most complete and well-prepared I have encountered for one of these USB instruments. It was written in Sweden, though, and the English is rather imperfect, but is understandable. You have to read the manual before using the instrument; the UI appears very simple, but there's a lot of hidden functionality. Triggering is not extensive: the unit supports normal analogue triggers, of course (we can say "of course" now, as it uses millions of transistors, not the 15 or twenty tubes of my Devry unit fifty years ago). Digital triggers are limited to edges (positive or negative) of any channel; if multiple channels are selected the trigger is the logical OR of them all. No patterns are supported. The user interface is simple and clean, and the screen updates very rapidly. It generally does a good job at issuing detailed prompts when an incorrect selection is made. The unit will generate two channels of analogue data. Triangle, sine, and square waves are supported. It is also possible to create quite complex digital patterns on all 11 channels, but I was not able to make either them or the analogue outputs work. No doubt there was some button I didn't press. Both the Windows code and the firmware is open source. I looked at some of the embedded code and it seems quite well-written. The schematic, too, is available, though one has to register the unit for access. One surprising feature is a calibrate mode for the scope. You'll need a good DVM. And there are a pair of variable capacitors for each analogue channel to compensate their input impedance. This is the first time I have seen this feature on one of these scopes. (Normally, one compensates the probes, so I wonder if this feature is for those using low-end probes, or maybe just hunks of coax.) The calibration is stored in EEPROM. The schematics show a very-well designed analogue front end. There were a couple of odd behaviours. I went into calibrate mode and then closed the window without performing a calibration. After that the unit would no longer capture data, issuing a cryptic CMD_STATUS_ERR dialogue box. The fix was to restart the Windows program. I got one error for overrunning the buffer while sampling at high speeds, but was not able to repeat that. Occasionally the USB connection would drop, requiring me to disconnect the cable and then reconnect; the UI would then recognise the instrument. There are a lot of other USB instruments that offer more functionality than available from the LabTool. Two features, though, make this a compelling choice. First, is the incredible price. Then there's the open-source code. One could enhance the product, change features, add more protocol analysers, and maybe even turn this into a data logger. Fiddling with the code would be a nice way to learn about working with embedded systems.

For my 8th grade graduation  (in the Catholic school system that's a milestone like finishing middle school), my dad gave me a Devry scope and VTVM combination. He had assembled the unit a few years earlier as part of a mail-order course in electronics. VTVM stands for "vacuum tube voltmeter," a long defunct phrase that described a high-impedance VOM (volt-ohm meter). The device was about 19" wide and maybe 25" deep with quite a few tubes. There was no case, and it's amazing I never broke the exposed CRT. The scope didn't have a trigger; in that tube era, trigger circuits were expensive, so it, like many others, had a free-running time base one adjusted in an attempt to stabilise the on-screen image. The unit served me well till late high school when I managed to save enough to buy and build a transistorized (though still with CRT as TFT screens were decades away) Heathkit scope. Both of those are long gone, and there have been many more scopes in my life over the years. Favourites include Tektronix's 7000 series of modular scopes. The high-end units we used in the 70s were fantastically expensive, had tiny little push buttons, and for the time offered unbeatable performance. The old Tek 545 I had for a while was a monster. It probably weighed 100 pounds, used vacuum tubes, but just ran forever. No one wanted it when it was time to move on, and I regret having to send it to the dump. For the last 15 years my main instruments have been Agilent units; the MSO-X-3054A that now graces my bench is a fantastic unit they'll have to pry from my cold, dead hands. In recent years some low-cost alternatives have come out. Rigol and others offer what appear to be fairly decent models in the half-a-thousand dollar range and less. Even Tek has some low-end sub-$1k units. I've not played with these but am very impressed with the specs versus cost. A lot of money can be saved by using a PC for the front end, and I've reviewed quite a few of these very inexpensive USB-based devices. Some are scopes; some logic analysers, and some a combination of the two, often with other features as well. The folks at Embedded Artists (a great name for a company) in Sweden sent one of their LabTool products, a scope/logic analyser/protocol sniffer/waveform generator. It isn't boxed; it's just two stacked and exposed boards as in the following picture. The LabTool Logic analyser "probes" (a wiring harness) are supplied, sans clips, but no scope probes. This is all not surprising considering the price: just 99 €, or about $135 at November 2013 exchange rates. That's a fantastic price. This unit is a little different than most of the others I've reviewed. There's no fancy FPGA sucking in data at high rates of speed. Instead, the unit uses a fast LPC4370 MCU, which has a Cortex M4 and a pair of M0s. Digital and analogue data is just sampled by the processor. Here are the specs: * 11 channel logic analyser that can run at up to 100 Msps. * 2 channel oscilloscope that runs to 80Msps with a bandwidth that varies between 3 to 12MHz depending on the channel's gain setting. * The digital and analogue channels can be turned around to generate signals. * It will decode SPI, I 2 C, and UART signals. * The digital zero vs one limit is 3.3V. But you can connect an external voltage source to change it to any value between 2.4 and 5.5V. As with most of these products, the sample rates depend on a number of factors. It can be as low as 20 Msps if both analogue and digital data is being sampled. The 47 page user's manual, downloaded from their web site, is the most complete and well-prepared I have encountered for one of these USB instruments. It was written in Sweden, though, and the English is rather imperfect, but is understandable. You have to read the manual before using the instrument; the UI appears very simple, but there's a lot of hidden functionality. Triggering is not extensive: the unit supports normal analogue triggers, of course (we can say "of course" now, as it uses millions of transistors, not the 15 or twenty tubes of my Devry unit fifty years ago). Digital triggers are limited to edges (positive or negative) of any channel; if multiple channels are selected the trigger is the logical OR of them all. No patterns are supported. The user interface is simple and clean, and the screen updates very rapidly. It generally does a good job at issuing detailed prompts when an incorrect selection is made. The unit will generate two channels of analogue data. Triangle, sine, and square waves are supported. It is also possible to create quite complex digital patterns on all 11 channels, but I was not able to make either them or the analogue outputs work. No doubt there was some button I didn't press. Both the Windows code and the firmware is open source. I looked at some of the embedded code and it seems quite well-written. The schematic, too, is available, though one has to register the unit for access. One surprising feature is a calibrate mode for the scope. You'll need a good DVM. And there are a pair of variable capacitors for each analogue channel to compensate their input impedance. This is the first time I have seen this feature on one of these scopes. (Normally, one compensates the probes, so I wonder if this feature is for those using low-end probes, or maybe just hunks of coax.) The calibration is stored in EEPROM. The schematics show a very-well designed analogue front end. There were a couple of odd behaviours. I went into calibrate mode and then closed the window without performing a calibration. After that the unit would no longer capture data, issuing a cryptic CMD_STATUS_ERR dialogue box. The fix was to restart the Windows program. I got one error for overrunning the buffer while sampling at high speeds, but was not able to repeat that. Occasionally the USB connection would drop, requiring me to disconnect the cable and then reconnect; the UI would then recognise the instrument. There are a lot of other USB instruments that offer more functionality than available from the LabTool. Two features, though, make this a compelling choice. First, is the incredible price. Then there's the open-source code. One could enhance the product, change features, add more protocol analysers, and maybe even turn this into a data logger. Fiddling with the code would be a nice way to learn about working with embedded systems.  

It was the early 1970s when I was sent overseas with three impressively sized racks of equipment controlled by a Honeywell H316 computer. Along with them came the orders to install the system and get it running. My adventure began when my boss sent me to a local one-week Honeywell computer course on machine language. That single course was the only training I received on this new system. Apparently, I couldn't be spared for the longer hardware courses, though my boss did allow a technician (who was going to the same location as the equipment) to attend. I only had to install the computer system, train everyone how to use it, and leave. That was the plan. The peripheral devices included a paper-tape reader, teletype terminal, large reel-to-reel digital magnetic tape drive, high-speed printer, data interface, and a huge hard disc. The hard disc was about a foot high and completely sealed inside a cylindrical enclosure that was pressurized with an included nitrogen bottle and pressure regulator. As I later discovered, it was fortunate that all the hard disc electronics boards were mounted outside the pressurized enclosure. "This is not me (or the system I installed), but it is a similar picture that I found on the Internet."—Steven Karty This was back in the olden days before BIOS ROMs told the computer what to do after being turned on. So I had to "fat-finger" in around 30 16bit words of instruction, which told the computer how to read the punched paper-tape reader output. Then I had to load an ASCII punched paper-tape into the paper-tape reader, which told the computer how to read the magnetic tape drive's output. Then I had to make sure that the large magnetic tape reels, which contained the computer program, were mounted and rewound to their beginning. Then, when I had everything ready, I would simply hit the start button, the computer would read the punched paper-tape, the magnetic tape reels would spin, and the whole system would start. This initialisation procedure had to be repeated each time the system was powered on. Before the system could be shipped, it had to be packed. Before it could be packed, everything heavy had to be removed from the racks and packaged separately. Although other people did the packing and crating, I first had to disconnect and remove the equipment from the racks and make sure that I would remember how to reinstall it. Everything went smoothly—at first. The equipment, the technician, and I arrived intact at our destination. I reinstalled and reconnected all the equipment, cued everything up, and hit start. Then things got rough. The paper-tape reader ran, but the magnetic tape reels refused to budge. Most of the hardware peripheral interfaces were not only unique and custom-designed, but also poorly documented. I called the technician over and asked for his help. We single-stepped through the instructions where the computer was stuck and figured out that the computer was waiting for the hard disc interface. The computer could not go onto the next step and tell the magnetic tape reels to spin until this disc interface was ready. After using a Tektronix scope to trace through the disc interface, we concluded that the interface was waiting for a signal from the hard disc. The technician then abandoned me, saying he had been trained only on the interface and not on the hard disc. As he slipped out, he mumbled that the "origin" signal from the hard disc seemed to be missing. I realised that I would be blamed if I couldn't fix the system. That I hadn't been allowed to attend any hardware courses was irrelevant. Unfortunately, there were no replacement boards for the hard disc. Fortunately, the system documentation included schematic diagrams of the hard disc electronics boards. Deserted by the technician and feeling very lonely, I picked up the scope probes and began tracing through every circuit where I thought the origin signal was supposed to go. I finally found the origin signal at the input to a potted delay line. But I didn't see anything at the delay line's output. In desperation, I decided to solder a jumper wire around the delay line. When I then repeated the initialisation procedure, everything worked perfectly! The manufacturer of the hard disc later said the design had enough margin so it did not need a delay line, but it sent a replacement anyway. In the end, all it took was just a piece of wire to fix this computer system. But I never would have found the problem, and thus its solution, without an oscilloscope. And I would have lost interest long before finding the problem if using a Tektronix scope were not so much fun. I met another technician (who had spent two years where I installed the equipment) before I left on this trip, and asked him for any hints about the site. He said it was nice and safe, so I wouldn't have any problems. That was only partly true, because I had stomach problems the entire time. I saw him after I returned and asked if he ever had any gastrointestinal issues. He said that while he always felt fine, his wife suffered from the same problem as I had described to him in such graphical detail. When I asked him what might account for the difference, he said his wife drank the local water but he drank nothing but beer. I didn't bother asking him why he forgot to tell me that before I left. But I still wonder if he brushed his teeth with beer. I still get a kick out of using Tektronix scopes because their triggered sweep circuits always work perfectly—which is why I finally bought my own. But it's an old analogue scope with a CRT. The new Tektronix scopes with their digital displays are way more fun. Steven Karty built an oscilloscope from an EICO kit in the mid-1950s when he was 10 years old. He started working in radio and TV repair shops at 13, became an amateur radio operator at 14. He has used Tektronix scopes almost exclusively for the last 48 years, and he has BSEE. He submitted this article as part of Frankenstein's Fix, a design contest hosted by EE Times (US).  

Here's a picture of my oscilloscope: a 1966 15Mhz Tektronix Type 422.   Vintage 1966 15Mhz Tektronix Type 422 When I bought my oscilloscope for twenty dollars, it was dead. Someone had tried to stick ten pounds of fuse into a one-pound fuse holder and subsequently broke the fuse holder. I replaced the fuse holder with a non-standard fuse holder and a fuse of the recommended type and rating, thus returning the instrument to a functioning capacity.   Vintage scope with new fuse holder. Now, the Tektronix Type 422 Oscilloscope is a fine instrument of quality manufacture, but I would like to try some of those new features they've come up with since the moon landing—features like 200MHz bandwidth, 1GS/s, 4 analogue channels, 16 digital channels, automated measurements, and FFT analysis that are provided by the Tektronix MSO2024B digital oscilloscope that is the prize of this contest, so I'm going to tell you this story. One day, I received a message from manufacturing that they had an instrument that was dead and that they required the assistance of my superior technical skills and extensive engineering knowledge acquired through advanced education and years of experience. So, I put on my anti-static smock and my anti-static shoe straps and grabbed my trusty DVM with the very pointy probes and headed down to manufacturing to render said assistance. Upon arriving in manufacturing and being shown the instrument, I asked the manufacturing engineer what was wrong with the device. He replied, "If I knew that, I would not require the assistance of your superior technical skills and extensive engineering knowledge acquired through advanced education and years of experience." So, I asked, "Well what's the problem?" He said, "It's dead." I said, "Well, what did you try?" He said, "I replaced all the boards with known good boards and the power supply with a known good power supply and it is still dead." He spilled the beans. I knew he would crack under my relentless questioning. As I sat down by the instrument, I bumped the table, which caused the screen to blink. So I banged on the table, causing the screen to blink again. I continued to bang on the table making the screen blink much to the amusement of the technicians working behind me. I did not care because I had a nibble and I was going to play it out before I got lost in the labyrinth of the innards of the device.   Handy troubleshooting technique. After several minutes of judicious banging, the screen came up and stayed on. I heard from behind me someone guffaw, "He's got it working," followed by laughter from the peanut gallery. I then took my pen and poked at the cables in the device until I found one that caused the screen to malfunction. I shut down the instrument and removed the cable. Then, using my superior technical skills and extensive engineering knowledge acquired through advanced education and years of experience, and using my trusty DVM with the very pointy probes, I determined that the cable was indeed defective; knowledge of which I imparted on the manufacturing engineer, thus proving the old adage that it is not enough to think outside the box. Sometimes you have to bang on the side. So please kindly consider my submission, though it is as badly stitched together as Frankenstein's monster (if Dr. Frankenstein had used duct tape) and send me that fancy new Tektronix MSO2024B digital oscilloscope that is the prize of this contest. I'm sure it will help in repairing those instruments I cannot fix by banging on the table. This article was submitted by P.C. (name withheld by request) as part of Frankenstein's Fix, a design contest hosted by EE Times (US).