Best oscilloscope choice?

[ayeaye]

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.

[ayeaye]

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.

[ayeaye]

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.

[ayeaye]

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.

[sm0ky2]

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.