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Author Topic: Best oscilloscope choice?  (Read 39856 times)

Offline ayeaye

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Re: Best oscilloscope choice?
« Reply #30 on: January 11, 2016, 03:58:08 PM »
I think i should exactify what i said about buying old analog oscilloscopes. As anyway i have responsibility. From the companies i said, it is said Trio and Kenwood oscilloscopes are not good, so avoid these. Others said not to be good, are Heathkit and Bell & Howell, so avoid these, in spite they often are the cheapest. What this guy from eevblog said to be good other than Tektronix, are Hitachi, GoldStar, Kikusui and Hameg. Also HP, but some say HP oscilloscopes are not so good. This guy knows what he says. He especially said that Hitachi is good, so prefer that, it's like the next best after Tektronix.

Some others who can be trusted, said that Iwatsu is good, also Leader. There is not so good information about the others, so see the reviews and learn more. BK Precision also seems to be appreciated, also some serious people seem to use Beckman and Philips. There was an excellent demonstration of a Tenma oscilloscope, and this oscilloscope performed just wonderfully, better than any other i have seen. But it was said, that such oscilloscopes, different from Tektronix, are not based on military standards. So when if buy Tektronix, you get a good thing, but then you pay twice more.

About the very old oscilloscopes, like these with vacuum tubes, the only ones they say can be used, are Eico and Telequipment. Like one can get an Eico 460 worth to buy from ebay in America, for $50 with shipping. These are only 4.5 MHz one channel, but one may find a use for them. One should consider with so old oscilloscopes though, that you most likely should replace just everything there, other than the crt tube and power supply transformer, so make sure these work. At that vacuum tubes don't seem to be a problem at all, as they seemingly can always be bought from ebay, so in spite of how it may seem, vacuum tubes are not really things to avoid. It is possible to get service manuals online, for almost all these. But it may cost to you more than buying a good 1980's 20 MHz two channel oscilloscope, so it is not exactly minimalism what concerns money, it may be minimalism just for the sake of it, or when you love restoring old oscilloscopes.

My oscilloscope still works fine. Except when i don't use it for some time, the potentiometers and switches somewhat play, until i move them back and forth a bit, then they work fine again. But that's normal.

Why some oscilloscopes are not so good, like some analog oscilloscopes or pocket or usb oscilloscopes. Because their circuits, such as amplifies and triggering, are so primitive. Things become more complicated when measuring changing things, Like the amplifies themselves contain capacitances and whatever, which cause distortion and interference. So what can be wrong. Everything can be wrong you can imagine. The can be unstable, like show different values at different times, with no way to fix it. They may distort the signal. The may cause interference, like additional oscillations in your signal. They may make the signal to be unstable and change fast, when it really doesn't. Because of instability of the signal or a primitive triggering system, they often may not be able to trigger. At that things may be fine, when you just measure a 60 Hz sine signal, but you see problems when you go to any higher frequency or hae a more complex signal. At that, it may not be fine even then. Like some Heathkit oscilloscopes show some sharp angle at the bottom of the most perfect sine signal. More than that, some even show you always a sine signal, no matter what the shape of your signal is.

So consider, this need for quality, is not for having a very high precision measuring equipment. So one should consider these requirements, just to have an instrument which you really can use for measurements. Not a thing which shows funny things on a screen, which may also look like nice, but that really cannot be used for anything useful. Especially when you are using it for things like overunity, one should be especially careful, as measurement is everything there.

When buying an oscilloscope, as i said, the best when on its picture there is a signal on the screen, especially when you don't feel being able to repair an oscilloscope. But this eevblog guy said, it's enough when they say that it is working. Then the very minimum is, that it's said that it powers on, and something appears on the screen, like a dot. Less than that, don't even consider buying, unless you need some spare parts from that particular scope. Because when the power supply transformer or the crt tube doesn't work, then this scope cannot be even repaired. Don't rely on sellers saying that this scope was just not tested, or they cannot or have no means to test it, this doesn't assure you anything, and it's also often questionable, that they pretend to be so stupid that they cannot test an oscilloscope anyhow. Don't rely on statements like, the oscilloscope is in good condition, this may mean anything, like it looks nice, but its crt tube doesn't work. Look for clearly saying that it works, because when it works, there is no reason that prevents the seller from clearly saying so.

About auctions, it is better to buy items from ebay, that you can buy at once. Because auctions are often a anipulation in ebay. Consider most of the bids mostly come in the very end of the auction. The buyer can also in some cases choose not to sell to the highest bid, so he can use his sock puppet or a good friend or business partner, just to pump the price up. What concerns old oscilloscopes though, auctions can sometimes be considered. Like there are auctions where they couldn't sell the oscilloscope at all, and sometimes it's an oscilloscope worth to buy, which one can get cheaply. It is possible to see in ebay, what items were actually sold, and with what price. So when you see an oscilloscope in an auction worth to buy, and before the very end of the auction there were no bids at all, you may consider buying it, you may get a bargain. But avoid the hazard, that is, maybe i can get it cheaply, think seriously about the reasons before going for anything.

I also found a new method of using oscilloscope. Like, often you have to calculate a power, and all you have are oscilloscope images, like of the voltage and current. Then what you can do, is to draw these graphs in gschem. Gschem has a very simple output file, just a text file for vector graphics. And from that file, like use python to calculate the bower based on two graphs of the oscilloscope signals.

What concerns my oscilloscope, i didn't have to do any repair. All i did, was a minimal calibration based on the oscilloscope's calibration signal, and even that was almost correct. The biggest problem was the cleaning. I used a strong cleaning agent for painted surfaces, no it doesn't damage plastic parts neither make them less shining, but you may first try out at some less visible place. Plus some graffiti removal pads maybe. I got it nicely clean, even the yellow on the light plastic parts, goes away with this. The only problem, the paint seems to be somewhat oxidized, as it is darker than it originally was. Some paint polisher may improve that, but i did not risk that, to damage the paint anyhow. It is also no problem to paint the metal case, it can be easily taken apart so that only the sheet metal remains. But this is not necessarily a good thing to do, as the original paint is a great value.

The metal parts i cleaned only with a tooth paste, maybe a lack of my imagination, but it was enough, makes them nicely shining, removing dirt and also oxide. The moving parts of the handler needed oiling, for which i used vaseline. The knobs are sometimes somewhat bent, as they hit them with heavy objects or then like to put the oscilloscope to stand on its knobs, doing that carelessly. A knob has a long rod, that is fixed at one end with a screw or something. It can be taken out and bent straight. I have one knob bent slightly, which is almost not noticeable, and causes no problems. But i did not risk to make it straight because this is a somewhat risky, as the rod has to be perfectly straight. I could make my scope nice and decent looking, all i think is necessary. I wrote this just to give you some idea of what it takes. Nothing much, it's mostly just cleaning. Unless there is some knob missing or such, and you have to replace it with some 3D printed one, or something. But in this selfless overunity effort, using an oscilloscope with some knobs missing, is i think a sign of pride.

Oscilloscopes, these things show us the nature. Not what we used to see nature is, but nevertheless it's nature, the ways we may not used to think about it. Beautiful as it always is.

Hope this was useful for some. And hope that it makes you not to hesitate to buy an old oscilloscope. The risk is not so great as you think, if you think everything well through, i think in 90% of the cases you will get a good working oscilloscope. And you will discover what a fun dealing with such old oscilloscopes, really gives you.
« Last Edit: January 11, 2016, 07:43:48 PM by ayeaye »

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Re: Best oscilloscope choice?
« Reply #30 on: January 11, 2016, 03:58:08 PM »

Offline FatBird

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Re: Best oscilloscope choice?
« Reply #31 on: January 13, 2016, 08:01:09 PM »
Ebay has some good values for the money.
Here is a Sinometer brand for under $200 with free shipping.

                                                                                                                               .

Offline AlienGrey

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Re: Best oscilloscope choice?
« Reply #32 on: January 13, 2016, 11:53:12 PM »
Ebay has some good values for the money.
Here is a Sinometer brand for under $200 with free shipping.                                                                                                                             .

Your having a larff it's got nothing on it, i wouldn't wast your money! you can get a Regol DS 1054z for £250 and look at the diffidence !
 
https://www.rigol-uk.co.uk/Rigol-DS1054Z-Digital-Oscilloscope-p/ds1054z.htm#.VpbSBlIVvcshttps://www.rigol-uk.co.uk/Rigol-DS1054Z-Digital-Oscilloscope-p/ds1054z.htm#.VpbSBlIVvcs

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Re: Best oscilloscope choice?
« Reply #32 on: January 13, 2016, 11:53:12 PM »
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Offline ayeaye

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Re: Best oscilloscope choice?
« Reply #33 on: January 14, 2016, 12:24:39 AM »
Ebay has some good values for the money.
Here is a Sinometer brand for under $200 with free shipping.                                                                                                                             
$200 with shipping, good value for money? I'm talking about old oscilloscopes one can buy from $50 with shipping, to $100. Good, completely working oscilloscopes, one can use for anything.

But you have $200 to spend? Great, then buy this one http://www.ebay.com/itm/Tektronix-Tek-465-Oscilloscope-with-Factory-Installed-DM43-Multimeter-/281903775425?hash=item41a2c63ec1:g:wQIAAOSwZG9Wjx2s  Tektronix 465, 2 channel 100 MHz, refurbished, calibrated, tested, has probes, excellent scope. The same TinselKoala had, if i'm not mistaken, ask him, he can tell you plenty of things about it. And all for $186 with shipping if you are in America. That is, it depends on where you are in America, but if you are in America, you can certainly get it for less than $200 with shipping. If you are in Europe, you should find scopes sold in Europe, as these things are heavy and their shipping costs a lot. But i don't know where you are, so i brought that as an example. Now compare that to this 10 MHz single channel Sinometer, these things cannot be compared, simply cannot be. This Tektronix is so good that i cannot even dream to have a so good scope, yet i'm satisfied with the one i have, it is a good scope and works well.

But this Sinometer. 10 MHz, one channel. Ok, you don't need more than 10 MHz, Ok, you can do with one channel, as it has an external sync. But this frequency is not only about range, it is about quality. These scopes are known to give different readings at different times, they are also likely unstable, and have plenty of interferences. Some people say, they can only be used to see wave forms, and it it is a question how reliably they do even that. So you want to buy that for $200, just to find that this is true? And nothing can be done about it, this is caused by its primitive circuit. You will find that it's just useless for anything. And after a year ago it will make a buff of smoke, and seizes to work beyond repair, as some people have said. They make many similar scopes, but they are all the same, likely made in the same factory in China, only the case differs a bit. They are known to be the most primitive, and made carelessly. They are low quality not only what concerns the electronics, but their physical parts often break as well.

Yes they are small, and resemble some old oscilloscopes with vacuum tubes, though they have no vacuum tubes. This also includes a tiny screen, which is not good at all, but overall yes, they look lovely. But all the negative about them still makes that worthless. And small, an oscilloscope doesn't take so much room, you can manage to put one at the corner of your desk. And, like having a Tektronix oscilloscope on your desk, this looks great, impressive for everyone who sees it. Everyone has computers, but not many have oscilloscopes.

But this thing, it is minimal, right. But i don't understand such minimalism. If you are minimalist in that way, you should rather buy an old Eico 460, you can get one for $50 with shipping http://www.ebay.com/itm/Vintage-Eico-Model-460-Wide-Band-Oscilloscope-Electronics-Repair-Tester-/231807804023?hash=item35f8d26277:g:aUwAAOSwJkJWkCDs  It is 4.5 MHz, one channel, and has triggering and external sync. And make it to serve you well. That one you can actually use, in spite old, it is a usable oscilloscope. Different from that Sinometer, do all you can to keep away from that scope.
« Last Edit: January 14, 2016, 02:31:49 AM by ayeaye »

Offline ayeaye

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Re: Best oscilloscope choice?
« Reply #34 on: January 14, 2016, 10:33:14 AM »
I'm sorry for this Tektronix 465 i referred to. I selected "buy it now" in ebay, and also only looked at oscilloscopes with "buy it now". So it had to be "buy it now" when i found it, it is very unlikely that i didn't notice the auction. I don't know what it is, but something is wrong there. That oscilloscope is most likely good, but the seller may screw up the price, using weird tricks. So, sorry again and be careful.

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Re: Best oscilloscope choice?
« Reply #34 on: January 14, 2016, 10:33:14 AM »
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Offline Paul-R

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Re: Best oscilloscope choice?
« Reply #35 on: January 14, 2016, 04:22:53 PM »
EEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEE

Relationship between: - Frequency of circuit under test and Mhz, sample rate of scope needed

EEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEE
.
Understanding this is vital. Can someone explain how to arrive at the required Mhz and sample rate needed to examine frequencies under test?

(Slow running motors should be able to use the Winscope software, with probes going into the soundcard)

Offline TinselKoala

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Re: Best oscilloscope choice?
« Reply #36 on: January 14, 2016, 05:03:57 PM »
1. No, I don't have a Tek 465, but they are fine scopes, if a bit complicated for a beginner. If you buy one make sure it's working 100 percent. They may have problems with switches and pots, due to age, but these are usually easily fixed by exercise and cleaning. Ask the seller, make sure you can return it if not working properly.

2. Don't buy a single-channel scope. These are special purpose items and are not as useful as a two-channel instrument. You will often want to look at the relationship between two (or more) signals and there is no way to do this if you only have one channel available.

3. Stay away from very old scopes like that Eico. They will probably need to have most or all of their electrolytic capacitors replaced in order to work properly. Unless you are a collector or just like fixing old stuff, it's not worth it for someone who wants an instrument that is actually useful on the bench.

4. The general rule about bandwidth is 5 times the fundamental frequency of the signal you want to examine. So a 100 MHz scope will "honestly" tell you what's going on in a 20 MHz signal, as far as risetime and amplitude is concerned. Of course you can use the scope for higher frequencies, but it won't show you the true amplitude of the signal nor will it accurately report rise times or other fast transient phenomena. This is true whether the scope is analog or digital. But DSOs have another thing to worry about: Aliasing. They can show you a completely different waveshape than what you are feeding into it, depending on sample rate. This is one thing you don't have to worry about with an analog scope.

5. While (almost) any scope is better than no scope at all, I would recommend staying away from "sound card" scopes or USB scopes that use your computer as display and control. Sound-card scopes have very low bandwidth and are clumsy to use. USB scopes can be good, but the good ones are as expensive as a low-end bench DSO. The cheap ones like the 20 MHz 60-dollar Hantek... well, I suppose they are better than no scope at all, and they do come with a set of probes that would cost about 20 dollars just on their own.

My advice: for between 100 and 200 dollars, look for a simple analog scope like the Tektronix 2213a or 2215a or similar 60-100Mhz bandwidth 2-channel unit. For 200-400 dollars --- save up and get something like a Siglent 1000 series or a Rigol DS1054z. If you absolutely must have a scope right now and you can't afford more than 100 dollars for the foreseeable future, consider a USB scope like the 20MHz Hantek, but beware....

And have fun! The oscilloscope is the King of Test Equipment and no electronics experimenter's workbench is complete without one.

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Re: Best oscilloscope choice?
« Reply #36 on: January 14, 2016, 05:03:57 PM »
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Offline Paul-R

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Re: Best oscilloscope choice?
« Reply #37 on: January 14, 2016, 06:05:17 PM »
That's a handy rule of thumb, TK. x5.

What about sample rate? How does that fit in (apart from some sort of "the more the merrier" yardstick?)

Offline sm0ky2

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Re: Best oscilloscope choice?
« Reply #38 on: January 14, 2016, 06:48:53 PM »
back in the late 80's, early 90's they developed processors that clocked in the Ghz range,
and along with them came scopes that could read the signals.

of course, just like most of the "real technology" of our world, we don't get to play with them for about 50 yrs after development, and while that time is approaching, they are still tens of thousands of dollars, and out of reach of the average person.

By the time we can get them, our computers will be running on synthetic diamond processors clocking in the TerraHertz, and most people wont see THOSE scopes till the year ~2058
(THz O-scopes were fully functional by 2008, using two different technologies)

TK gives good advice on the low-range scopes, I've owned a few, but most of what I care to play with these days is far beyond the reach of an affordable scope.

 really kewl stuff happens at wavelengths approaching the atomic resonance scale  :)

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Re: Best oscilloscope choice?
« Reply #38 on: January 14, 2016, 06:48:53 PM »
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Offline ayeaye

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Re: Best oscilloscope choice?
« Reply #39 on: January 14, 2016, 08:08:47 PM »
All i know about how the bandwidth of an analog oscilloscope is defined, is that it is the frequency where there sine signal is reduced to 70% of its original. Higher than that frequency, and almost nothing comes through. And this is only about sine wave, any harmonics you want to see, must also be within that bandwidth.

What concerns the USB oscilloscopes, then i rather prefer to have a glorious decent old scope, with all the funny things on it, than this small cheap box containing some questionable electronics, and you can get it for the same price or cheaper. Also that eevblog guy doesn't quite agree with TinselKoala about these cheap USB scopes, and i trust that guy, he really knows what he says. They should start to make some cheap analog scopes for the beginners again, as they once did, but they don't, and this Sinometer is just an accident.

What concerns the Eico, i meant, who is truly a minimalist and wants to have a minimal scope, should rather consider buying that old Eico, than that Sinometer. Yes i know one may end up replacing almost all components there, but when one is such a minimalist that can go to buying that Sinometer scope, just to have a minimal scope, then much better would be to buy that Eico. Because there will be an equal trouble of doing anything at all with both of them, but when one repairs Eico, then at least one would have a useful scope, though only minimal. But this will never happen with that Sinometer scope, even when one is very good at electronics, one likely cannot make it anyhow useful, because of the flaw of just everything in it. Who doesn't want to repair a scope at all, as i said, should buy a working scope, but pay somewhat more, though not much. As i did, and i got a scope which i didn't have to repair at all, and it works well until this day.

Old Tektronix scopes tend to be expensive in ebay, and much more tricky to buy, because they are the most sought after. This is why i talked about other alternatives of old scopes, which one can get much more cheaply from ebay, but that are still good working oscilloscopes, all what a beginner may need. Like this LG (GoldStar?) oscilloscope, $110 with free shipping, it has a test signal on the screen, and it is evidently working http://www.ebay.com/itm/LG-Dual-Channel-Oscilloscope-Model-OS-5020-20mhz-/331680874379?hash=item4d39b87f8b:g:mUUAAOSwo6lWHUId . But it is likely a good oscilloscope. This was "buy it now" when i posted this, when now the seller again changes to auction, be careful and notice that and better avoid buying it, but please don't blame me then.

Old scopes should not be wasted, they should be added to the armory of overunity researchers :)

Offline ayeaye

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Re: Best oscilloscope choice?
« Reply #40 on: January 16, 2016, 10:57:59 PM »
Ok, this is a video about that Sinometer 10 MHz scope https://www.youtube.com/watch?v=EutGR4xbs48 . I'm certain that this is exactly the same, as they sell these cheap scopes under many different names, but all of them are exactly the same.

200 Hz, a frequency which should not cause any problems, and it doesn't seem to even trigger. He touched the trigger adjustment knob, but apparently found that it cannot trigger. Why they chose 200 Hz when they could choose any frequency, may well be that on higher frequencies the signal is just horrible. And even with that 200 Hz, other people say, the amplitude it shows is different every time you measure.

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Re: Best oscilloscope choice?
« Reply #40 on: January 16, 2016, 10:57:59 PM »
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Offline ayeaye

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Re: Best oscilloscope choice?
« Reply #41 on: January 17, 2016, 05:37:12 PM »
Why does the intensity of the signal on that Sinometer vary so much? The image below is during showing that 200 Hz sine signal, this is all that is visible on the screen at a time.

I don't know what this thing is, but it is not oscilloscope the way i used to know oscilloscope is. It seems to be some piece of scrap electronics, just named oscilloscope, so that people would buy it.

I could once even buy that oscilloscope, that is some of the types of it, which i'm sure they are all exactly the same. I hesitated between that, and that Hitachi oscilloscope. I'm so glad that i decided to buy that old Hitachi oscilloscope, as now i have a normal working scope.

That it is 20 MHz and two channels, makes me a bit sad, as i'm minimalist. But i had nothing to choose from, because i didn't want to go to replacing all parts of a vacuum tube oscilloscope, also Heathkit and Bell & Howell they say are not good and reliable, so there was nothing else to choose. Also at the time i didn't feel to be able to repair oscilloscopes in any way. And the cheapest dso or usb oscilloscopes were not cheaper, and i didn't find them to be any usable oscilloscopes either.

So i, kind of, found that the 20 Mhz 2 channel oscilloscope is not that bad. These were the oscilloscopes they made the most, so there is the greatest supply and the price is the cheapest. So i guess one has to satisfy with a 20 Mhz 2 channel scope, unless one succeeds to find any less powerful oscilloscope, that is also working, which is a matter of a kind of rare chance. And an oscilloscope which is not Heathkit, Bell & Howell, Trio or Kenwood don't know more old oscilloscopes that they definitely recommend not to buy, but there may well be more.

So realistically, the choice is either some 20 MHz or more two channel oscilloscope from 1980's or 1990's, or then an old Eico or Telequipment oscilloscope with vacuum tubes, with replacing most of the parts inside. The latter is the right choice for a true minimalist, who also can do some electronics, well, not a rocket science is necessary for that. Provided that doing that also gives fun. Why i say Eico or Telequipment, because, other old oscilloscopes with vacuum tubes are not said to be usable. You may find out more, and maybe there are some that are, but most are Heathkit tha certainly are not. Also with such old vacuum tube oscilloscopes there is a high risk that there are no regulators or anything, so you get some rather arbitrary readings, which is not true for Eico or Telequipment, they are often very simplistic. One may say, there are also old Tektronix scopes with vacuum tubes. There are, but Tektronix oscilloscopes with vacuum tubes tend to be huge, with a large number of vacuum tubes. Thus these are not really realistic options.

What concerns this sinometer oscilloscope, dso oscilloscopes, usb oscilloscopes and all sorts of other scrap, or oscilloscopes made of an old crt tv-s, then one more option is to make the circuit yourself. This option though is the most difficult of them all, as a really usable oscilloscope's circuit is not simple at all, it is very complicated. It is also not stardard, and depends on the particular crt tube, components or whatever you use. So this is for people who know electronics very well, thus it is not any option for beginners.

But i think, unfortunately very likely you would have to satisfy with a 20 Mhz 2 channel analog scope, and not anything less. As bad as it may sound.

What concerns auctions, i say, never go to auctions, buy only these that are "buy it now", most items are such and there is plenty to choose from. But if you still decide to go to the auction, then. The most reasonable is to go to auction when until a few hours before the end of the auction, there are still no bids. But when you still decide to participate in an auction otherwise, then. Start bidding only a few hours before the end of the auction. Find out the price of the similar items, and decide the reasonable price with which it makes sense to buy that item. Then bid only to that price and never higher, suppress the hazard to bid a bit more. Because, the seller or his business partner, may be your opposite bidder. If that's so, and the auction ends, that opposite bidder will not agree to buy the item, and the item is yours with the reasonable price, you bid it to. Also other bidders may refuse to buy the item, when they bid too high, and again the item is yours. But again, never go to auctions, this is an unnecessary waste of time and effort, too risky at well. Good sellers also rarely sell items on auctions, they don't play any games and waste their time to that, their only business is selling their goods.

One more thing, the price of shipping. Some think, what matters is the price of the item, and the price of shipping is some inevitable expense, in addition to that. But you should know that you pay the price of shipping to the seller, and thus it can be that the seller gets an additional income by setting the item's price low, but the shipping price high. You cannot see the real shipping price anywhere, even when you receive the item. You may deduce it from the shipping price of a similar items by the same shipping service, but even there are several options. It doesn't really matter for the seller, which way it is. Thus always consider the price together with the price for shipping. Find out the reasonable prices for shipping for similar items, and think twice when the shipping price is much higher than that. Use the cheapest shipping options, don't choose the more expensive ones, they don't guarantee that your item arrives in better condition. Don't choose fast shipping as the time is almost never that critical, and it is a real waste of money.

Hope that was anyhow useful for anyone.
« Last Edit: January 17, 2016, 08:43:38 PM by ayeaye »

Offline ayeaye

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Re: Best oscilloscope choice?
« Reply #42 on: January 18, 2016, 08:01:43 AM »
As you see on that Eico 460 that they sell in ebay, different from that below, the horizontal selector is on external, which means that it is in x-y mode, and there can only be a dot on the screen when no probes are connected.

Offline ayeaye

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Re: Best oscilloscope choice?
« Reply #43 on: January 23, 2016, 04:38:50 AM »
It is difficult, as i'm not any expert in oscilloscopes, yet i have to explain. So i try, have to try. By what people said, and based on what i read from its manual, Eico sems to be a so-called repetitive sweep oscilloscope, and so likely are most vacuum tube oscilloscopes. Repetitive sweep oscilloscopes are older types of oscilloscopes, which were there before triggered sweep oscilloscopes. Instead of triggering, these oscilloscopes seem to change the frequency of the sweep, to frequency which is the closest harmonics to the frequency of the measured signal. This means that they cannot be used to measure any time characteristics of the signal, because the sweep frequency varies and is not really known. Neither does it enable to measure the phase difference of two signals, in spite that it has an external sync. For that reason Eico likely is not a reasonable choice, it is not an oscilloscope in what we used to know oscilloscope is.

Eico 460 also has a non-standard input resistance, so the standard probes cannot be used, they should either be modified, or one should make ones own probes. There is the schematics of the probes though. It also can be used only with 120 V mains power, that is in America, it has no means to switch to 250 V. In spite that said, it is a useful oscilloscope that works well for certain purpose. Like it was widely used for tv repair.

Thus the only oscilloscopes worth to consider with vacuum tubes that i can say, are Telequipment oscilloscopes, like the s51b below, from 1970. This oscilloscope has triggering, that is, it is a triggered sweep oscilloscope like all the modern oscilloscopes. It also has an external triggering. Telequipment was a branch of Tektronix, making not as good oscilloscopes as Tektronix, yet for that reason all its oscilloscopes seem to have triggering. This may be a reasonable alternative to that Sinometer, if one is a true minimalist, but likely after some repair. It can be used with both 120 V and 250 V mains power. An example of it sold in ebay http://www.ebay.com/itm/Vintage-Telequipment-Oscilloscope-S-51B-/111207579502?hash=item19e47cff6e:g:a5wAAOxyLN9SeBSJ , this one costs $72 with shipping to America. It has at least a dot on the screen, so it is at least repairable. But if repairing old oscilloscopes doesn't interest you, an old 20 MHz 2 channel oscilloscope is still better for you.

At that this Leader oscilloscope is said to be "tested for all functions" (does it mean that it's working?) and it's only $69 with shipping to America, so less than this vacuum tubes oscilloscope, and it's 20 MHz and two channels [search ebay for Leader 1021, and the cheapest, the url makes all the text here too wide]  . It is a scope from 1980's likely though, so likely doesn't satisfy true minimalists, but what concerns price, it may not make sense to buy less powerful oscilloscopes.

Hope this helped to make things more clear.

Offline sm0ky2

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Re: Best oscilloscope choice?
« Reply #44 on: January 23, 2016, 06:43:12 AM »
the 2  best ways ive found to get a quality scope at an affordable price is:

1) take the time to go to Estate Sales until you luck out.,

and
2) the U.S. Education spares no expense on getting the good stuff.
when a school upgrades their equipment theres usually 30-50 scopes that get sold out the back door.
ive gotten a few this way over the years.


 

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