Cos6100m oscilloscope

[shovenose]

Should i buy it? I dont know how it works and it doesnt come with anything but the big piece. Do i need a probe ?(and what is a probe anyway)

I can get it for a couple bucks. When i plug it in amd press the power button then an led on it lights up. Other thwn that i dont know if it works. Its 100mhz i think
So what do you think?

[PCBONEZ]

It's Analog.
I'd skip it unless it's really cheap or for a learning project.

[Th3_uN1Qu3]

So what's wrong with analog? It's a great tool to learn on. For a couple bucks, buy it. You can build a probe yourself, it's not too hard. It'll make switching power supplies so much easier to understand.

[PCBONEZ]

What's wrong with analog? - Oh my!
You can get a working digital for ~$100 if you're patient.
I wouldn't spend more than $50 for a WORKING analog.

[shovenose]

Well id get it for $20. And i can bring it back if it doesnt work. So how hard would it be to make a probe?

[PCBONEZ]

$50 for a WORKING analog. - With probes.

By the time you pay for the BNC and cable and clips [and probably shipping] you might as well have bought probes.
http://cgi.ebay.com/New-Two-Oscillos...item563fcc5715

[Krankshaft]

A good analog can outperform any cheap Wan Hung Lo brand $100 and under e-bay scope. Are they cool toys certainly can they give you waveforms yes. But I wouldn't trust their accuracy especially voltage measurement if a repair job depended on it.

A REAL standalone digital scope a Rigol 50 Mhz for example runs $395 new for perspective on price.

Good digitals are great but I'd rather have a good analog than a half baked digital any day.

[shovenose]

Ok so probes cost like $15. Cool. When i brig it home ill let u guys help me interpret the manual

[Krankshaft]

A just took a look at a pic of it kind of looks like they were trying to mirror the Tektronix control panel a bit.

[PCBONEZ]

Analogs miss things like sporadic spikes because the refresh wipes it on the next trace and your eyes won't see it.
With a digital [or a 'memory' O'scope] you can do one shot and hold the trace for as long as you need to look at it.
Analog are best for signals that repeat exactly the same over and over.
Not ideal when looking for things like noise and ripple that might have a spike every 3 or 4 refreshes.

$100 for a 100MHz used working Digital is realistic if you have patience.

http://cgi.ebay.com/TEKTRONIX-2232-1...item4cf18d5485

http://cgi.ebay.com/TEKTRONIX-2232-1...item230a1a302c

Or even a 300MHz.......
http://cgi.ebay.com/LECROY-9310M-100...item4aa4a92cdf

You can find them on Craigs List too.

Mine cost $285 but it was calibrated, it's a Main Frame, I got different 6 plug-ins with it and all the Operating -and- Service manuals for the scope and all the Plug-ins.
I can reconfigure it to be different scopes. - I like it like that!

There are a few 1Ghz Main Frames these plug-ins work in.
Once in a while I check for a deal on one but it's a 'I want' thing, not a 'need' thing
.

[Th3_uN1Qu3]

Originally Posted by PCBONEZ

By the time you pay for the BNC and cable and clips [and probably shipping] you might as well have bought probes.

I paid $8 for BNC conectors and cable and clips at a local electronics store. They don't have $15 probes 'round here, at least not locally. But yea, a store-bought x10 probe is nice to have. My x10 probe uses a piece of twisted wire in place of a trimmer, and it was a bit of a pain to set up. But once calibrated it's served me well so far.

Originally Posted by PCBONEZ

Analogs miss things like sporadic spikes because the refresh wipes it on the next trace and your eyes won't see it.
With a digital [or a 'memory' O'scope] you can do one shot and hold the trace for as long as you need to look at it.
Analog are best for signals that repeat exactly the same over and over.
Not ideal when looking for things like noise and ripple that might have a spike every 3 or 4 refreshes.

My analog scope can do "one shot" too. So your point is?

Originally Posted by PCBONEZ

$100 for a 100MHz used working Digital is realistic if you have patience.

Those deals look good admittedly, but at least in some parts of the world, shipping is expensive. This doesn't apply to the OP as he's in the US, but for me at least, it does. However selecting a digital scope is harder than an analog, because the number of samples per second is as important as is the claimed bandwidth. On many digital scopes the claimed bandwidth numbers occur only with repetitive signals - and haven't you said that the most important feature of a DSO is "one shot" mode?

For me a digital would be convenient only because it can compute handy things such as amplitude and frequency by itself. Other than that, the analog i have does fine.

[kc8adu]

at least see if it makes a trace.

[shovenose]

Originally Posted by kc8adu

at least see if it makes a trace.

what does that mean i mean when i press the power on it there will be a green dot on the screen for a second?

[PCBONEZ]

Originally Posted by Th3_uN1Qu3

My analog scope can do "one shot" too. So your point is?

To do that your scope needs a memory in order to record the trace to repeated on the sweeps.

That means it's a memory o'scope [mentioned earlier] which is transitional between a true analog scope and a fully digital scope.
The only difference really is that the data isn't digitized before committing it to memory.

The other way they accomplished that early on is a special phosphor coating that glowed for an extended time after the sweep.
The problem with the coating is it makes using the scope for 'normal things' a pain in the butt.
They are usually single purpose scopes.

Being a digital scope is not about displaying numbers on the screen or doing math. It's about digitizing the signal. There are lots of DSOs that don't do math or display numbers.

.

[PCBONEZ]

Originally Posted by shovenose

what does that mean i mean when i press the power on it there will be a green dot on the screen for a second?

You should be able to get a flat line.

[Krankshaft]

Just make sure the time base dial is all the way to the right and you see a solid straight line. If it's too far to the left a single dot will appear and won't move. No deflection is very bad for CRT phosphors and can cause burn in.

If you have a probe hook it up to one channel and touch it to the calibrator bar on the front. It's a square wave oscillator for compensating your probes but will let you know if the scope can display a trace. On Tektronix scopes it's a round u shaped bar but it's got to be on this scope somewhere.

Turn the volts per division down and you should see a bunch of square waves. The tops of the squares will probably be a bit distorted since your new probes haven't been compensated yet.

Ahh CRT digitals very nice now those can be gotten cheap. Whenever I hear digital scope I associate it with a modern LCD display.

[Th3_uN1Qu3]

Originally Posted by PCBONEZ

The other way they accomplished that early on is a special phosphor coating that glowed for an extended time after the sweep.
The problem with the coating is it makes using the scope for 'normal things' a pain in the butt.

This is how it's done on mine, it goes something like "switch to one shot mode, crank the brightness to max, set trigger level, hit the arm button (and watch its pretty green glow), then wait for the trace to flash and interpret it while it's still there".

Admittedly it is a bit inconvenient, but it gets the job done. The phosphor responds fast enough for "normal things" when brightness is kept at reasonable levels.

[TrippKJ4BKD]

I own a Kikusui COS6100M 100Mhz scope. Paid $160 at a local Ham radio fest. I probablly paid to much. I really like the scope worked good when Nutralizeing the tubes in my old Kenwood hybrid rig. I made some probes for it. But eventally decided to buy a cheap set for $20 bucks on ebay. The factory made probes work much better. I have'nt really learned to do a lot with the scope yet, but enjoyed using a teroid core wraped with wire to wave over the transformers and see them oscillate on the scope. You can really see nice oscilatting pattern if the transformer is oscilatting. It's not a perfect test but gives you an idea if the transfomer is doing something. I have a Blue Ring meter but like to see the patterns on the scope. Well anyway I really like the scope and with 5 channels I think it has more than enough functionallity for me.