Oscilloscopes

ting an oscilloscope. I don't have enough money for the $400 digital oscill oscopes. My family does not have a lot of money and the ones on ebay are st ill too much expensive. I'm just wondering if anyone has an old analog osci lloscope that I could have. Thanks :)

Ebay does. Until then there's free soundcard scope software. You can also u se a dead CRT tv as a crude scope, but beware of overheating the crt neck b y overscanning.

NT

You should first get an idea of what you intend to *do* with the 'scope! E.g., troubleshooting digital kit places different requirements than analog kit.

Similarly, low voltage, high voltage, etc.

And, the speeds (bandwidths) of the signals of interest -- as well as their temporal natures (e.g., "one shot" events are examined differently than repetitive events).

Buy what you think you will *need*, not just a "checkoff item".

Since you don't say where you are, the issue of shipping cost comes up.

At local hamfests and electronics flea-markets around here, old analog scopes in the 10-to-15 MHz range can often be had almost "for the asking"... I've seen 'em for $20 or so (sometimes with only one working channel, sometimes just fine).

One of my friends was actually given one for nothing by a neighbor who was getting ready for a garage sale. I cleaned it up and we've loaned it to one of my former office-mates as a learning and teaching tool for his kid.

For almost any of these older analog 'scopes, the cost of packing and shipping it to you (from anywhere) would probably exceed the value of the scope.

I live in the U.S. State Minnesota. Hope it helps.

After the Hamfest, many items that did not sell end up in a dumpster behind the building.

Fred

On a sunny day (Thu, 14 Aug 2014 15:59:29 -0700 (PDT)) it happened snipped-for-privacy@care2.com wrote in :

It probably will burn in in a second if you do not turn brighness way down. Maximum f on the V coils even with a good amp would be maybe a kHz, or wind your own coils. better build this:

I am not selling my 10 MHz analog scope for anything below 5000 Euro :-) Nothing can replace that. if he can get his hands on an old scope CRT he is already half way there, I build several that way DG7-32 based and Russian CRT based.

48$ 43 cents ex shipping

Normal TV mode operation of the horizontal scan is about 15kHz plus lots of higher harmonics. You get 2 timebase frequencies depending which coil you connect to.

Overscan can kill these things with a bang. Moving the scan coils forwards reduces the potential for it.

NT

If you had asked a year ago and paid the shipping I could have helped myself. Do some research on your local Amateur Radio Groups and asked around that crowd. They often organise Radio Rallies and Hamfests where such items are oftn bought and sold. Another place might be if you have a reasonably local computer club who hold similar events.

Regards

Paul E. Bennett IEng MIET Systems Engineer

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It might be worth going to a few hamfests, don't know your city, here is a list of hamfests in Minnesota. You can modify the search if you are close to ND, SD, Wi, etc.

I have 60 MHz Hitachi V650F I want to sell, It is a great scope and I'm selling it with probes. It has delayed sweep, It all works good. Price $130 plus shipping, but the shipping from Fl to MN could be $40 to $60 I haven't checked. If you check ebay there is one for $80 plus $25 shipping. No probes or power cord, not tested, but as they say, "pulled from a working environment" Mikek

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On a sunny day (Fri, 15 Aug 2014 02:15:25 -0700 (PDT)) it happened snipped-for-privacy@care2.com wrote in :

There is in that case a much simpler way that does not need any mods to the teefee, If you are satisfied with the 15625 Hz sweep that is.

Make a free running V and V generator linear ramp. Compare to 2 voltages, one a pot DC level (horizontal position), the other the input signal (vertical position). AND the outputs of the 2 comparators. Make sync pulse from H and V down going ramp. Add output of AND gate on top of that sync. Feed to video input teefee or some RF modulator input and then in antenna input teefee. I'v done this, displayed 500kHz square qwave TTL with the >> MHz spikes. But then your source needs to be in sync with the H osc, or sync the H osc to a fraction of the input signal. Works great. The idea behind it is from old teefee 'trick generator', you create a dot on the screen (video), and can move the position of the dot. For very LF demos it is great too, Cost just a few transistors, I used UJTs and PNP current sources for the ramp generators, and diodes for the and gate, and BFY90 transistors diff pairs for the comparators. I demoded it to somebody, and later heard somebody made a product of it, probably patented it hahahaha. Anyways that was 1976 or there about.

I like that idea :) Maybe will try to do something with it when I get one of those round tuits, thanks.

NT

On a sunny day (Fri, 15 Aug 2014 05:58:04 -0700 (PDT)) it happened snipped-for-privacy@care2.com wrote in :

Here is the circuit diagram as far as I remember..

There are a few not so obvious tricks in here. The 2 diff amplifiers are in balance when he ramps on the input equals the voltage on the H and V position potmeters (or V input signal). In that case the collectors are high, and via diodes D1,2,3,4 point A and point C the base of Q6 is high, 'white'. In ANY other case one of the collectors of Q3,Q5 and / or Q10., Q12 is lower, and the base of Q6 is less positive (pulled a bit down), so black. So there are basically 2 window comparators, anded with the diodes. the size of the windows, this is the H and V size of the white spot, is set by the current sources of the diff amps. The sync happens when the UJTs discharge the caps, and drive Q9 low, this will pull the output low.

Do not remember exact component values. If you cannot figure it out I can enter it in LTspice one day, should run just like that (has spice UJTs?).

I have drawn Y input via a cap, but of course it is basically DC coupled, add a FET perhaps. Q1 Q7 are current sources just to make linear ramps.

This was about that circuit, give or take a resistor or something.

Yup, that's what I was going to suggest. Here is how to find the local club:

All it may take is a phone call. Like Paul I had an analog scope from my younger days in almost-as-new condition. Last year I donated it to a school. Most serious radio hams have numerous scopes and would love to give an older scope to the next generation.

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Regards, Joerg 

http://www.analogconsultants.com/

Nope. I just for the hell of it did a web search for electronics surplus pl aces there and went to a few websites, and there ain't all tha tmuch.

Someone mentioned eBay, which is alright but you can't check things out bef ore buying. You get Craigslist there ? That can be a good source for some t hings, like scopes. Deal face to face and at least you can check the thing out.

Definitely get an old style analog scope, referred to as a CRO. Keep it sim ple. Try to get a trace on the screen that moves with the positioning contr ols fo less than fifty bucks. They are out there.

Textronix is the last word in analog scopes. However, a Tenma works just fi ne. The Tek will have a better trigger circuit, but other than that, the El Chepo wil work just fine for most things. I would say get just about anyti ng, 15 or 20 mHz bandwith. That is plenty to learn on. I have an old 422 an d a Tenma 72 dash someting, and there is really not all that much difreence . Of course the old Tek can withstand a nuclear holocaust, but if that happ ens I don;t really care.

Or maybe we'll sell you the HP. Not top buck because it is not aful alignme nt and the dual timebase doesn't work. But it will come with a parts unit. At 275 mHz it is one of the fastest analog CROs ever built. Alot of the new er ones digitize the input and read it to the CRT at a slower speed. This i s one of the last "real" ones. Belongs to my partner, not sure what he woul d take for it but if interested ask and I will ask. The best scope we got r ight now, BUT, we are Tektronix people. The HP is a 1725a. I had to put the vertical outpurt IC in it and then found the dual timebase doesn't work. D ecided I don't care and there it sits. You could probably take a board from the parts ubit and et that function working. And then you have to learn ho w to use it. I wouldn't bother in the beginning. As a scope it already work s.

You guys would drool over this, I still have one of these. B & K 1403 in great shape!

I have not turned it on for some time but I know it works..

Maybe I'll part with it :)

Jamie

I still have my Tema, bought it new back in the 80's. I see there are a few on ebay that command a fairly high price. WHat is nice about it was the component Bannana input, makes checking zeners easy.

Just be careful, some of the CRT's don't have the brightness they once had.

Good thing is the manuals always had the schematics in them.

Cheers

Hi I just checked this and john I would like to have the oscilloscope and i'm wondering where on the website your email is? All of the emails are to fluxeon.com. I couldn't find the other site so i don't know if it was there.

Cassete size? Is it one of those small hand size ones?

A cheap piece of '60s TV shop crap.

Use it for a wheel chock.

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