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OT: Oscilloscope Purchase

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  • #16
    X2 for the Tek TDS scopes, eBay is covered with them recently. I hear nothing but good about the Fluke scope meters, but they are a tad pricey for me. It's time to update a bit... LOL my Tek 545 was property of Raytheon in 1953!
    Last edited by nickel-city-fab; 04-15-2021, 12:48 PM.
    25 miles north of Buffalo NY, USA

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    • #17
      Originally posted by J Tiers View Post

      For instance, looking at the two gate drives of an SMPS which can be several hundred volts different from each other, AND on the mains side.

      While one can actually "do that" with a regular 'scope, it involves a lot of kludges and does not work that well. The upper gate drive on a half bridge SMPS is varying in base level by several hundred volts at the switching rate, and you are looking for a 15V signal superimposed on that.
      Exactly. Basically it amounts to channels that are completely walled off or isolated from each other. They do not share a ground, so on each channel the ground side of the channel can be floated to wherever it needs to be. Handy for looking around in SMPS or even looking at the separate phases of a 3-phase motor, etc. Without isolation the only way to do that is to have a differential probe for every channel AFAIK. You can float a regular scope's ground by using a two prong cord, but all the channels will still share the common ground rail. And it's not a safe thing to do, very easy to get hurt with a wrong move or touching the wrong part of the DUT or scope. Add/subtract between channels can be used in certain cases while leaving the ground cable from one channel out of the equation (it is already tied to the others on an unisolated scope) but then you lose half your channels, and it's usually a real good way to introduce noise/ringing, etc.

      And yeah I love my Teks, they are great. The only thing I like better about the modern scopes is the size/portability. My two needed a little TLC but that wasn't a big problem. One needed some relays on the hybrid acquisition boards replaced, the other needed some CRT tweaks. I upgraded them both to TDS784 state as well. Both are working perfectly now.
      Last edited by eKretz; 04-15-2021, 03:28 PM.

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      • #18
        OK guys, I am very, VERY familiar with the Tek 465. I could probably operate one with my toes and blindfolded. They were in every, and I do mean EVERY TV station and other video facility where I worked over 45+ years. They were THE scope and I suspect it was very hard for Tektronix to retire that model number. But space is a concern. Both of my electronic workbenches are small and already crowded. And there is little available floor space. So I do want something smaller. On top of that, I sold my Tektronix scope just a few years ago for much of the above reasons. As much as I would love to have another Tektronix scope, I do not think it would be a 465.

        Perhaps a newer, used Tektronix would be nice.



        Originally posted by Mcgyver View Post
        Hard to beat the venerable Tektronix 465b for a few hundred dollars with probes. That stuff was built properly! and if something does go wrong there is a ton of documentation. I bought a "WON" digital scope some years ago. An " acquaintance" brought it back from the States. What a POS, didn't last a year. I think it used it 3 times. Trail was cold though, buddy (asshat really) never gave me a receipt, vendor was out of the country etc. $500 wasted and the China rip off quality fires stoked again lol
        Paul A.
        SE Texas

        And if you look REAL close at an analog signal,
        You will find that it has discrete steps.

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        • #19
          Yes, there are Rigol models that are "hackable". The same internal hardware seems to be sold with different software and a different front panel where only the model number is different. And you can find hacks on the internet to upgrade them.

          I suspect that a large reason why this is possible is because there are only a few chip sets being used and the front ends (probe inputs) are much the same. Also the sampling rate on the current crop of low cost, imported, digital scopes is always around the 1G rate. Some two channel scopes seem to share that 1G sampling circuit between the two channels so each one only gets 500M sample rate. And many entry level, four channel scopes have two sampling circuits that are shared between the four channels. You have to read the specs carefully. After that point it is the software that takes those samples and draws the trace, filling in the points between them as needed. On a four channel model is is often possible to get two 1G sampling rates by using channels 1 and 3 to bring the second circuit into operation.

          I suspect that much of the difference in the software is simply extending the interpolation algorithm to a higher frequency while still using the same limited number of samples. But beware because a 100 Mhz spike displayed using only 5 samples will be different from the same spike displayed while using 10 samples. There really is no free lunch, but you can probably get a quick snack without paying. And this is also the case with analog scopes. I have spent many hours starring at a waveform wondering if that small bump is really a significant spike.



          Originally posted by boslab View Post
          Did I not watch a video, Australian guy EEV Somthing, about the Rigol, apparently you can update the features as they are all the same chasis/board to give the features of the higher spec at the basic cost, better check it out as I’m certainly not better than basic with scopes ( mine was a tecktronics with an actual crt. And plug in modules, expensive in its day but found its way into a dumpster when something else better came along, in fact the dumpsters at the research lab were a fascinating thing, I’m still using an AVO8 I fished out, leather case, leads everything, stamped property of British steel ltd)
          Mark
          Paul A.
          SE Texas

          And if you look REAL close at an analog signal,
          You will find that it has discrete steps.

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          • #20
            Like Stan, above, I have the Hantek DSO 5102P. It works well for me, but I'm not an EE. Hantek went out of their way to help me out when I had a senior moment and stuck a 10X probe into a magneto ignition output on a small engine! They sent me a new main board free, I did the replacement.
            Southwest Utah

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            • #21
              Recently bought a Keysight from Newark. $500+tax, they start at $250. Pretty happy with it as a stand-alone unit. If you want to download stuff they want to sell you their $$$$$ software. Only other complaint is it uses a USB 2.0 (read slow) for downloading.

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              • #22
                I have a couple old hp 400Mhz digitizing scopes and while they work good, they aren't portable and need power provided somewhere else. My wife bought me a fnirsi-1013d import scope. Its labelled as 1G sample and 100Mhz, but from reviews it sounds like it's closer to 20Mhz. I really like it since its battery powered and really easily transported.

                I'm just a hobbyist with no official training, so I cant tell ya much more than that.

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                • #23
                  There was a small lab I worked where strip steel thickness gauges were made ( I got the greasy bit btw!) the thing had a moving cobalt 60 source on top of a c frame around the steel strip and a giant detector ( bloody big block of acrylic with photomultiplier do dahs) to set this up required a really fancy mc fancy Agilent scope and spectrum thing, the boss who was doing all the doings got these things in, I asked him that looks fancy how many queens heads there, I spat my coffee out, bloody nearly 1/3 million, I did not think it was possible, the service contract was more than my bloody house, I was new and had a lot to learn, I now know why a hammer costs 3000 to the military, what a strange world
                  Mark

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                  • #24
                    At my work I have a Rigol 1054Z that I find quite nice. It is only a 50Mhz scope but that is plenty for what I do there and the 4 channels are handy at times. I just got a Siglent SSDS1202X, dual channel 200Mhz for my bench at home. A lot of scope for under $400. I have not used it extensively at this point as I have only had it for a couple of weeks, but so far as I have used it I really like it. Triggering is good, display is good, the storage function has already come in handy, and should be reasonably intuitive to use for anyone familiar with a scope.

                    This replaced a Tek 2215 I've had for a long time that works great, but was more limited. I was in need of storage capability and as a bonus, the Siglent takes up far less space on my small bench. I think it is worthy of consideration.



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                    • #25
                      Originally posted by nickel-city-fab View Post
                      Siglent seems good, but quite honestly I prefer used Tek over almost anything else. You can get them down around $200 nowadays for a 2-ch 100mHz digital storage unit that works fine. Just for old times sake, my main scope right now is a 1953 Tek 545 mainframe scope with the vertical amp plug-in. That also works just fine. Good for audio and AM work.
                      Heh. I have a 545 buried in a closet - bought it 30 years ago from a surplus guy who was going to strip if for the tubes. I got him to give me an extension cord and powered it up, ran it through all the ranges, got it for $75.

                      In 1960-62 I helped Tektronix make the 545A - after they came off the production line I calibrated them. Learned a lot there.

                      I've also got a 514AD in that closet. Early '50s, I guess.

                      My favorite was the 465, though. I have lots of company there.

                      -js
                      There are no stupid questions. But there are lots of stupid answers. This is the internet.

                      Location: SF Bay Area

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                      • #26
                        I use some older Tek lunchbox scopes at work which would be in your price range, but really a Rigol or Siglent should do nice. I picked up a Siglent power supply for a test fixture for work, .001v and .001a resolution and had all sorts of neat options, trend graphs for voltage and current, timers, USB and Ethernet control. It was about $600 because the EE wanted an extra digit in resolution.

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                        • #27
                          Well, like I said: eBay is awash in newer Tek TDS series scopes. And other ones that would fit in a shoebox. All digital, etc. I'm considering one myself in the medium future. Among other things (HP distortion analyzers oscillators etc. And I miss my old Kepco pwr supply. Disclaimer: last time I was active in electronics, *all* my stuff was rack mounted. As in, a rack next to my desk.)

                          Originally posted by Paul Alciatore View Post

                          Perhaps a newer, used Tektronix would be nice.
                          25 miles north of Buffalo NY, USA

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                          • #28
                            Originally posted by nickel-city-fab View Post
                            X2 for the Tek TDS scopes, eBay is covered with them recently. I hear nothing but good about the Fluke scope meters, but they are a tad pricey for me. It's time to update a bit... LOL my Tek 545 was property of Raytheon in 1953!
                            The older Fluke are fairly cheap. Mine was under $300, and I got some other unrelated stuff with it at that price.

                            The bad news is that I did NOT get the interface cable nor software for downloading the stored traces. I have wanted that from time to time, although I worked around it the old way by simply taking a pic of the screen.
                            2730

                            Keep eye on ball.
                            Hashim Khan

                            Everything not impossible is compulsory

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                            • #29
                              Originally posted by Jim Stewart View Post

                              In 1960-62 I helped Tektronix make the 545A - after they came off the production line I calibrated them. Learned a lot there.

                              -js
                              Got mine at a Ham festival for $15, had some bad grounds in the plug-in. Re-soldered and works fine ever since. You'll be glad to know the calibration still seems to be OK according to Mr Fluke. Mine has Raytheon property tags. If you want, I can get the ser. number off it for you sometime.
                              25 miles north of Buffalo NY, USA

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                              • #30
                                I started with Tektronix CROs around 1970. Wonderful machines. Yeah, went through the full range as others have mentioned.
                                My last Tek was a TDS 220. Over time it needed repairs to the PS and to the front-end BNC connectors. That was OK. Then the LCD died. Um.
                                I was a bit disappointed with the lack of support from Tek: no cct dia for the PS as it was bought-in from China.
                                So, search on ebay.

                                Hantek DSO5102P looks exactly like a TDS-220. In fact, I now suspect that Tek bought the TDS 220 from Hantek as an OEM job, which is why Tek did not have cct diagrams. It is virtually an exact copy. No learning curve. And light enough to prop up on the CNC when it needs some TLC.

                                So, new DSO5102P. It does the same things as the TDS 220, but in colour (oh wow ...) Sold the TDS 220 to someone technical (with full disclosure) who is now trying to buy a functional replacement LCD screen from ebay. The first one was DOA.

                                The DSO5102P is presently monitoring the current through a brushless DC motor fan out of the fridge. Every now and then the fan seems to lose one phase, and makes a horrible noise. But right now ... the two last replaced fans are running perfectly. I dunno ... May have to look inside it.

                                Cheers
                                Roger

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