HP 54602B OScope Single Capture Issue - Page 1
Forum section: electronics / testgear

author: RoboTechEd
author_rank: Regular Contributor
timestamp: April 20, 2015, 03:53:44 am
content: Hi All!Sorry about the repost, I notice I originally posted the below message in the 'Other Equipment' category by accident. Couldnt delete it, but moving here because its more applicable. (source)I recently acquired an HP54602B scope as my first scope. I am pumped! I want to look at a waveform in single capture mode but am having issues. When I single capture the waveform it successfully stops. I then try to zoom in/adjuct voltage axis and the screen goes blank. The only apparent way to get back to my waveform is to press the 'Stop' button. When I do that it returns me back to my original settings. This is a Digital scope, so I should be able to zoom in on the waveform correct? Is there something in missing? In university I only worked on new scopes, so this is eluding me.I attached a video of the issue below. Hope GDrive links are OK on the forum. I am editing the horizontal axis off camera, but I am trying to.Video of the issue:LINKThanks!

author: K5HJ
author_rank: Regular Contributor
timestamp: April 20, 2015, 07:02:57 pm
content: The 54602B only samples at 20 MSa/s so a single shot event is not its strong suit.It can capture 2000 points so there's not a lot of room to look around at a captured waveform.Randy

author: mike_kawasaki
author_rank: Contributor
timestamp: April 20, 2015, 11:05:59 pm
content: The 54602B is about 25 years old (think introduced in 1992 while I was working at the HP Colorado Springs Scope Division). I'm going by my old memory but believe the following is true:* The 54602B is basically a repetitive scope -- it builds the waveform through multiple acquisitions (versus a single shot scope)* The 54602B can only build a waveform on screen -- once you change the timebase then it deletes all acquisition informationOf course, newer scopes have much longer memory and incredible ability to post-process a waveform. These 54602B limitations were the impetus to creating the MegaZoom technology. The design team heard repeatedly that they wanted to zoom in and out, so they developed an ASIC -- and thus was born the 54645 family!Happy to stand corrected on any points since been a long time since I touched a 54602B (but still get nostalgic when I see them in one of our lab rooms).Mike

author: RoboTechEd
author_rank: Regular Contributor
timestamp: April 21, 2015, 03:26:53 am
content: Quote from: mike_kawasaki on April 20, 2015, 11:05:59 pmThanks Mike! Coming from University, this surprised me. I figured the issue must have been with me, and not with the scope. Your post below told me more info than a while Googling did, good memory.What was the advantage of only building it for the screen? I would figure it would fill the buffer on trigger, and then adjust the scope of where it looks based on what edits you make to the timebase/voltage base? Was this advanced for the time, or just not as in-demand? I guess logic level stuff wasn't as big then as it is now, so zooming in and out wasn't as necessary.Thanks for the history lesson too! Very interesting to see when certain features started to be introduced

author: tautech
author_rank: Super Contributor
timestamp: April 21, 2015, 04:24:14 am
content: Quote from: RoboTechEd on April 21, 2015, 03:26:53 amHmmmLogic level IC's have been around nearly as long as scopes, 40+ years.Ask your Prof about "glue logic"Driving the old CRO's was the key to obtaining expected waveforms and now DSO's just make it sooooo easy.Even entry level DSO's have a trigger suite that exceeds anything that was offered in top line equipment a couple of decades ago.Why you would even consider getting anything other than a recently manufactured DSO escapes me.Do you have the knowledge, skills and equipment to maintain a 25 yr old CRO?IMO, considering the equipment you use at Uni, you have taken a step back in time.

author: RoboTechEd
author_rank: Regular Contributor
timestamp: April 21, 2015, 04:49:19 am
content: Quote from: tautech on April 21, 2015, 04:24:14 amI was just commenting on how it is much more prevalent now than ever. My EE classes were strictly focused on digital logic almost (albeit, I was an Electronics and not an Electrical), and with FPGAs/MCUs becoming incredibly powerful and at a low cost I have to imagine digital logic is more popular now? I feel like anyone older who is an experienced EE focuses on analog, while anyone younger is focusing on digital. That is just my observation though.And yeah, this is a step back. I get that. I have an Analog Discovery for any low-speed things I'm doing. I just happened to win this at an equipment liquidation auction and I didnt have a bench OScope yet. I will likely use it strictly for analog purposes. One day I'll be sure to upgrade to a 1054z or something equivalent, but for now I think this fits my needs pretty well. The only problem i'v experienced is the zooming issue (so far)

author: Howardlong
author_rank: Super Contributor
timestamp: April 21, 2015, 11:48:59 am
content: Treat it as a learning experience. Until recently, my only scopes for a decade had been a 2465B CRO and a Tek TDS 2024B DSO. For five years I just lived with the TDS 2024B. I just didn't know any better, I just sit at the desk and design and develop stuff. And I designed and developed an awful lot of stuff with those scopes.Then I started using eevblog...What's startling is that the difference between the 54602B and the 5462x series sold as its replacement. The difference is huge in terms of functionality and specs, as Dave rightly stated in his review of the 54622D, they still hold up today, not just from specifications but also use-ability. During the 54600 days, there was good reason to have both a CRO and a DSO, with each complementing each other. The 5462x series turned a page in that respect, and I've yet to use a DSO that's as easy to use.

author: mike_kawasaki
author_rank: Contributor
timestamp: April 21, 2015, 04:21:35 pm
content: Quote from: RoboTechEd on April 21, 2015, 03:26:53 amIt is basically a factor of the technology involved and the shift from analog to digital. The 54600s were extremely popular and one of the first digital scopes that gave you an analog-like user interface (go look at the 1980 scope and you'll be freaked out on how it even works) and very fast screen update rates.There were just design trade-offs in creating the first 54600s. As a history lesson this project was called "Jedi" in the lab. The Colorado Springs Division had Star Wars names for the scopes and Star Trek names for the logic analyzer (both of them designed in Colorado Springs).Mike

author: Howardlong
author_rank: Super Contributor
timestamp: April 22, 2015, 11:44:01 am
content: Indeed, I have a 1980b, I yearned after one of these back in the day, and picked one up on ebay recently.I did a video of my baby(!) a few months ago herehttp://youtu.be/Nbig45nkETkKeeps the lab warm, but the UI is a bit "unique" shall we say.

author: RoboTechEd
author_rank: Regular Contributor
timestamp: April 22, 2015, 03:20:18 pm
content: Quote from: Howardlong on April 22, 2015, 11:44:01 amThat is quite the lab you have there! So many screens. Have to imagine the 40 other screens are also keeping you toasty. Thanks for the video. That is a cool looking scopeQuote from: mike_kawasaki on April 21, 2015, 04:21:35 pmI'm loving this trivia knowledge! Ill have to study up on the history of scopes and see what times what advances came around and how they were implemented. Hopefully 25 years from now I'll look back at the 1054z and talk about how revolutionary it was, but also how the features are too limiting for the time (like with the 54602B)