looking at buying myself a cheap portable scope for use when teaching and troubleshooting a bot. Was originally thinking about eBaying an old HP or Tekt, but buying one sight unseen is giving me the heebie-jeebies.
Keep seeing some of the ARM based scopes (agptek, jyetech, others): does anyone have any experience with anyone of these? Should I bypass these and just get an OWON or something similar?
Requirements are 2 channels, < $200, no PC needed, fast enough to watch PWM outputs going to servos and/or motor controllers, ability to trigger (as opposed to freerunning).
(or does anyone have a good working HP or Tekt looking for a new home?)
You missed the summer hamfest season, but check out ARRL Hamfest search page and put your zipcode or state in. There are indoor swap meets across the winter, you may find something in your price range. Hams are pretty good about explaining what you are looking at. But as always, if it seems to good to be true, it isn’t. :rolleyes:
Although it’s a bit above your budget, I highly recommend the Rigol DS1052E. The DS1052E is considered by many to be the best oscilloscope in it’s price range. It’s a 50MHz scope, but can easily by hacked to operate at 100MHz
Did you see the DAQ for NI
Data acquisition (DAQ) is the process of measuring an electrical or physical phenomenon such as voltage, current, temperature, pressure, or sound with a computer. A DAQ system consists of sensors, DAQ measurement hardware, and a computer with programmable software. Compared to traditional measurement systems, PC-based DAQ systems exploit the processing power, productivity, display, and connectivity capabilities of industry-standard computers providing a more powerful, flexible, and cost-effective measurement solution.
Parts of a DAQ System | See a complete guide to building a measurement system https://lumen.ni.com/nicif/us/ekitdaqsys/content.xhtml
I just recently had a fine result buying a used Tek 2230 (100 Mhz digital storage) from ebay ($199) Yes there is some risk, the secret is taking the time to find one from a highly rated individual seller that knows its history and knows for a fact that it is in good working order. I would also recommend shopping in this generation of scope, which was before fully digital but with some digital storage functionality. A true analog trace but with storage, comparison, zooming, triggering, etc. These scopes cost $5000+ in their day but can now be had for nothing. A real sweet spot in the price/value range. Getting a modern digital scope with the same quality of signal and fequency range would cost far more than you are looking to spend.
I’ve found that buying an older scope off eBay isn’t as bad as it sounds. You can find a 50MHz scope (much higher bandwidth than is needed for FRC robots) for about $80-$100 from a seller with a return policy. I have a tek 2230 just like jspatz1 (100MHz dual channel) that I bought w/ a refurbished power supply for $200. It also came with a service manual and two 100mhz probes. It’s interesting because it has a completely analog mode where you can see the dot move across the display when you have set a slow sweep speed and it’s just like an old scope, and it has a digital storage mode, which lets you perform measurements.
Can’t help it, it’s my job. Seriously though, I haven’t had a 453 to use in a while, we are currently using Tek TDS2024B. Takes almost as long to boot as an old tube type to come on but it is so much lighter. It sits on my bench instead of a cart on the floor. Of course there is nothing like an old 524 to sit next to on a cold morning. For that matter we still miss the old Ampex 1000 or an RCA TRT-1B for a nice warm feeling in a cold tape room. http://videopreservation.conservation-us.org/museum/
I thought that all this new digital TV was just a bunch of ones and zeros, so what’s sync have to do with it? :rolleyes:
I agree, the 453 was a TV man’s scope. The 465 is a nice all round unit for general use and it’ll sync to NTSC, just not as simply, especially when you’re focusing on vertical sync or closed captioning data. (Would I be showing my age by mentioning Teletext?)
Yes those older scopes can be a bargain for what you get these days, but be sure to consider all of your needs. Do you have a place to easily store it? Will you want to take it with you? How reliable will it be. Some older scopes can become cantankerous after many years of use and they are not for everyone. There are several inexpensive scopes out there that will do any work needed for FIRST robotics, and come in a small easily portable and easy to use package. They are well worth considering.
I had an older analog scope at home and it was more trouble than it was worth. All those analog switches and knobs were well past their useful life, and they also did not like sitting around in an unheated sometimes damp basement. I would need to twist all the knobs a bunch every time I used it and then it might still flake out a few times while I was using it. I rarely would completely trust the result. It got to the point where I was spending more time tinkering with the scope to get it working correctly than on what I was supposed to be fixing. I find the new crop of small modestly priced digital scopes to be ideal for home electronics use. just my opinion.
I 3rd the Rigol if you are buying new. I’ve got one of their fancier models with the local analyzer functions and it was tough to beat for the price.
I also have an older HP 100MHz DSO, 2 HP older 300MHz oscilloscopes, 5 Tektronix scopes and I sold my old dog house scope complete with cart and vintage accessories to someone with the spectrum analyzer module out in Dayton in 2000 (funny part was I drove the rig to Dayton, OH and sold it to a guy that lives really close to me in NJ just by chance…could have saved the cart and put up an ad at the supermarket). I got the FFT function in the newer Rigol scope but I have all the crazy modules (including the microwave modules) for my old HP mainframe spectrum analyzer (cell phones sort of fix the need for the old scope cameras).