Help with Oscilloscope purcase - Page 1
Forum section: electronics / beginners

author: MyZirconia
author_rank: Contributor
timestamp: May 12, 2010, 09:47:49 pm
content: Hi Dave and All.I have a question about purcase an oscilloscope, there is a friend of mine who have for sale a used Fluke PM-3384 Autorainging Combiscope for ~120 USD and thequestion is: is it a good scope for the money? and he said it had both analog and digital i have looked around on the inernet but cant find any reviews on the scopeis the samplerate good or bad? i would be glad if i get some inputs about my questions.Thanks in advanceMagnus CarlssonSweden

author: Kiriakos-GR
author_rank: Super Contributor
timestamp: May 12, 2010, 10:00:36 pm
content: Hello Sweden , regards from Greece.Most important than all , are that this oscilloscope that you plan to get,to be recently checked if it is healthy ...The specs has secondary value.https://www.eevblog.com/forum/index.php?topic=509.0;topicseen

author: Polossatik
author_rank: Frequent Contributor
timestamp: May 12, 2010, 10:12:35 pm
content: If you cannot get a scope for free, like Dave keeps suggesting...,and this is working properly I think it's a rather fair price for this 4 channel scope.For "hobby" usage I think it will do just fine.( data sheet here )

author: saturation
author_rank: Super Contributor
timestamp: May 13, 2010, 12:14:38 am
content: That model was about when Fluke bought out Philip's test equipment company. Its a model from 1992, so its now about 18 years old. Its a very good one, I'd estimate its more 20 MHz given its 200 MS/s rate, and for $120 US, that's a steal. However, it could die on you any day, or give you over 10 years of useful life. As others suggest, a lot depends on how it is NOW, rather for the specs it was given when it was new. You won't be able to get any scope near that capacity for that price.http://www.eurekaspot.com/sp.cfm/DIGOSC/FLU/PM3384B-083.htmlNote, many good scopes have a self test, so just because it powers up and seems to make a trace on the screen, doesn't mean its really working properly. This scope will boot and do a self test before functioning, so it will signal all is well. The users manual is here:http://assets.fluke.com/manuals/PM3370B_umeng0000.pdfIs buying a scope complicated? Not really, but if you buy second hand, like buying a car, you need to know more about a scope or a car, to insure what you buy is really working and not get a lemon. If you buy new at least you know what the spec sheet says is likely what you are getting.Its one reason why I think those elcheapo 'toy' scopes that Dave maligns are a better deal for newbies, because it will work, its solid state, has less things to go wrong, true it may not have good or any input protection or good specs, but they are used mostly for DC to audio frequencies, general education, and if it breaks, at most you are off $100. If you do move above the DSO nano like scopes, you'll know more about what you want and what the DSO nano cannot do, and will appreciate and be able to choose good scopes better.http://www.justblair.co.uk/seeed-studio-dso-nano-pocket-digital-storage-oscilloscope-review.htmlFinally, true this great scope is $120, near the same price as the el-cheapo toy DSO nano. But the difference is the $120 buys uncertainty in the scope's performance while $100 for a new DSO nano, still under warranty, buys yous less features, but certainty.Quote from: MyZirconia on May 12, 2010, 09:47:49 pm

author: EEVblog
author_rank: Unknown
timestamp: May 13, 2010, 12:28:39 am
content: A 200MHz 4 channel analog scope would be a bargain for $120! but this is the combi-scope which are pretty good scopes, so even more of a bargain.If it works I say don't hesitate to grab it!200MS/s & 32K memory is reasonable, so it would be a handy digital scope.You could even resell it for big profit on ebayDave.

author: Unknown
author_rank: Unknown
timestamp: May 13, 2010, 08:48:14 am
content: While it is true that a new product is often guaranteed to work, if the Fluke scope still works after eighteen years, I'd guess that there's a fairly good chance that it will still work in another ten years (except for some items like batteries and electrolytics). I wouldn't be so sure about that for a DSO nano. Plus a DSO nano is probably worthless once you get anything like a real scope, but especially the analog part of this scope will be useful even if you get something like a Rigol DSO.I'd say it's an excellent deal. If it's a friend, you can probably test it before buying. If it runs through the self test without errors and displays a signal (eg. probe calibrator output) in both digital and analog modes (there's a clearly labeled button to switch), I'd say it's probably fine. I've never owned one, but used it once (a PM3394b I think), and thought it was a fine scope. The ability to switch between digital and analog on the press of a button is very useful. I wasn't a big fan of the controls: I prefer knobs to buttons for things like range settings, and I didn't like the menu's, but I'm sure I'd get used to it, and especially for the price, it'd be hard to do better. The autoset resets everything I believe (including input impedance and measurements), so you won't be tempted to use it.The digital sample rate is a bit slow compared to more modern scopes, but entirely usable. There haven't been many analog scopes developed since, so not much improvements there.

author: MyZirconia
author_rank: Contributor
timestamp: May 13, 2010, 12:43:52 pm
content: Hi All Again.Thanks for the inputs about the scope. I have been over to my friend who is selling the scope and we tried the self test option and it goes throug all tests without anyerrors so it seems to work,the manufactoring date says it from 1996 and where in for testing last time in 2002 before it got retiered in 2004 he says.Ok i will maybe buy the scope if it worth the 120 usd aprox.Thanks again for the help.Ps : what type of probes should i get to the scope since there whas no brobes whit the scope?Magnus Carlsson(in to Hobby electronics and Radio Amateur)

author: Unknown
author_rank: Unknown
timestamp: May 13, 2010, 01:15:21 pm
content: Choosing a scope probe.In short, get a 10x probe with a compensation range that includes the input capacitance of your scope and preferably at least 100MHz bandwidth.The scope probably has a contact next to the BNC to sense the attenuation factor (eg. 10x or 1x), and adjust the read-out automatically. To be able to use it, you're probably limited to compatible Philips/Fluke probes. You can often also set this manually, and if you can't, it's not that big of a deal, you can just do the multiplication yourself.I try to stick to brand names, especially for the higher bandwidth ones, since there's some real junk out there, and they're usually not that much more expensive used. Make sure you get at least the essential accessories like ground lead and grabber hook, and preferably more like short ground adapters and IC tip covers.

author: qno
author_rank: Frequent Contributor
timestamp: May 13, 2010, 04:03:11 pm
content: $120 for a 4 channel 100MHz is a good deal.I own a PM3394A (200 MHz) for many years and I love it.It was made by Philips. Half way in the 90ies Fluke bought the measurement division of Philips and they are still building the Scopemeter that was started by the Philips measurement division.I like the many features of the scope It has 1,2,5 and a a variable input selector as well that recalibrates the display. Probes can be adjusted as well as automatically selected. It has an auto calibration function. The calibration is based on a single current source and precision resistor. The time base is quarts based so much more accrate than the analog Tek's of that time.I worked at a company who bought them new. I am not sure about the numbers but then had the choice of the Tek 545 (??) series the HP 55100 (??) series and the Philips combi scope. The PM3394 was chosen because we could do a sanity check of the digital measurements with the analog part. I remember the HP had a samplerate of only 10 Ms/s making it unusable for fast single events. It went into equivalent time mode rather low in the ms/div range.Philips always had a very sharp CRT. The analog Tek of that day used a mesh in front of the tube to increase brightness at high speeds but this made the picture abit blurry compared to the Philips/Fluke.I have the extended math package installed (FFT a.o.)but I think Fluke sold the scope with all options enabled as standard.It has cursors, then a big improvement compared to counting divisions and calculating the voltage or time.If you can find the original probes you also have the command button option.

author: saturation
author_rank: Super Contributor
timestamp: May 13, 2010, 05:58:43 pm
content: This reads like the scope will be good risk and very well worth the money for a 14 year old item.Quote from: MyZirconia on May 13, 2010, 12:43:52 pm

author: orbiter
author_rank: Frequent Contributor
timestamp: May 17, 2010, 09:29:57 pm
content: I'll be getting myself one of thesehttp://www.owon.com.cn/eng/pds.aspin a couple of weeks. OK it's not the most expensive thing in the world and thus probably won't be the most accurate either, but for a beginner like me it'll do the job.I was all for looking for second hand Analogue scopes as Dave suggested but the problem is with shipping. I just don't fancy buying something that may be 10 years old and have it not work when it gets here due to being bounced around in a van. I'd rather just go for a new digital scope first off and get an instruction manual and a warranty with it

author: Pyr0Beast
author_rank: Contributor
timestamp: May 17, 2010, 10:52:53 pm
content: QuotePlease don't.I have the 5022 version. It does the job, but the LCD is of such a low quality it is simply horrible. Low resolution, low brightness, weird colours and plenty of 'lag'. Garbage to say. It is big, but it is also ugly.Input part and autodetection is good. USB cable is however much too short - can't even plug it into the nearby laptop without the extension - 20 cm for a 300€ unit, aww come on.You get 2 probes with the scope which is reasonable. (Is there a place where I could get temperature resistant probes ? I do kinda melt them occasionally)(SW is quite useless)It does not have a fan - is completely silent.And does not warm up much even after hours of work as consumption is only 3-5W.Get the rigol scope. It is just so much better.

author: orbiter
author_rank: Frequent Contributor
timestamp: May 17, 2010, 11:13:09 pm
content: Quote from: Pyr0Beast on May 17, 2010, 10:52:53 pmOK thank you for your views. I'll keep looking for a better one then or save up a little while longer for the Rigol.

author: saturation
author_rank: Super Contributor
timestamp: May 17, 2010, 11:44:57 pm
content: There's a vendor rep named Joy based in the UK who may have a scope in your price point, and from your URL, is more local to you in the UK.https://www.eevblog.com/forum/index.php?topic=357.0Quote from: orbiter on May 17, 2010, 11:13:09 pm

author: Joy at MCS
author_rank: Regular Contributor
timestamp: May 20, 2010, 01:57:18 pm
content: Regarding the PM scope:I do think these are good scopes and $120 is a good price but what I will say is something does go wrong my experience is that parts are hard to come by and the repair costs are not cheap. We had a unit that took 2 or 3 mths for the repair house to track down the part and the repair costs was quite a bit.On the otherhand, I do know people who have owned these scopes for years and not had any trouble with them but they did get the calibrated regularly.That's my 2cents for today :-)Joy

author: MyZirconia
author_rank: Contributor
timestamp: May 20, 2010, 09:29:09 pm
content: Hi all Again.An update of the scope purcase:it sits now nicely on the desk in my little workshop and it seems to work fine the little i have tried it the only thing i can complain about is that ittake up alot of benchspace it is quite deep but i have a plan to rearrange my little workshop so it wouldnt be a problem then.Thanks for all your input about the scope it helped me to decide to buy it.Keep on Posting.Magnus Carlsson