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I'm still very new at learning how to use a scope, but I'm getting mighty
frustrated.

I bought a used 464 and have been able to get it to display a straight line
as well as its square wave from the calibration thing on the back. But
beyond that, nothing. I have a little 9v "tutor" that is supposed to
generate different signals but I can't even get past step 1: read voltage.

I've watched tutorials online and get that there's a balance between the
delay and the volts per div knobs but no amount of adjustment will show me
anything beyond a straight line.

Maybe the generated signal is outside the range of this scope? Is there
another test I can do to see if it's even functioning?

Thanks for your help!

Rick

Hi David - thanks for your reply.

The knob is locked, set to auto, I set coupling to DC (it was on AC) and turned the volts/div knob up and down. All I get is a flicker and it goes back to that straight line.

For reference, this is what the tutorial is saying:

* Select AC coupling;
* Set time/div to 5ms/div
* set volts/div to 10v/div

There's a picture (in the tutorial) of a wave that says 7.83v and says to expect AC frequency of 60Hz.

Another behavior I noticed:

The tutor generator has a trimmer where you can adjust voltage down to 0. The flat line on the screen goes up and down but it remains a flat line.

Pseudo,

It sounds like you have dirty contacts with the position knob, v/div and possibly transistors inside.

Mark

Actually no, I haven't checked the voltage of the generator, but there is a light that says that it's "on".

Mark - jeez, that sounds perilous, huh? Mega high voltage in there?

Rick,

My first inclination is that your outside signal source is not working. Can you give us some sort of feeling for what type of signal that this device produces? This is a 100Mhz scope, so I cannot imagine a cheap device that would output a signal that this scope could not detect and trigger on. Since the calibrator works and produces a display, the scope must be triggering and mostly working. How are you connecting your signal generator or source to the scope?

If you are trying to measure a straight DC voltage, with the VOLT.DIV Selector switch set to the DC position, Trigger Mode to "AUTO" Trigger source to "NORMAL". This will get is a straight line but that line will move up or down depending on the potential and polarity of the DC Voltage that is applied. IF you are applying a 9VDC potential to the input, the applicable Volts/Div knob needs to be set in the 5V position (full Counterclockwise)..

First, with no signal applied, use the position knob to center the straight line on the screen vertically. When you then apply a 9V DC signal, the line will then show as a straight line, but should move approximately 2 divisions above or below the center line (depending on signal polarity).

The setup for a pulse, square, sine or triangle wave form will be different from the straight DC, since triggering will come into play.. .

--
Michael Lynch
Dardanelle, AR

Can you direct me to a web site describing this tutor device?
The first place to start is with a description of the signal. The next is to determine your expectations.

Do you have an instruction book for it? There is some information on the web. I did not search for a free instruction book but its worth your doing so.
?? Have you much experience using a scope?
?? If you can see the calibrator using a probe the scope is working. Try another signal source, even just put your finger on the end of a probe, you should see a lot of noise and probably hum. I am not familiar with the? 464 but from what's on the web it appears to be a fairly straight forward scope.
?? Do you have any other instrument that can confirm there is anything coming out of your "tutor"?.
?? See: <>

--
Richard Knoppow
dickburk@...
WB6KBL

Is it this gadget?


It requires an AC input, 9V to 12V. Is it possible that you have attached a DC source?

The behavior your describe where the line "bounces" up is what happens. With the variable voltage knob on the generator, the line will ease up and down as I turn it. Maybe it IS working then? I expected a sine wave based on the PDF from the tutorial. I link that here:

David - yeah, I have the ground plugged into where the tutorial shows. I've used both the 1x and 10x probe that came with the scope.

For reference, here's the tutorial: The behavior your describe where the line "bounces" up is what happens. With the variable voltage knob on the generator, the line will ease up and down as I turn it. Maybe it IS working then? I expected a sine wave based on the PDF from the tutorial. I link that here:

Clark - that's the one. It's a 9V AC plugged into the wall

Yup, it shows a ripply, moving wave when i touch my finger to it...I can
never get it to be static though (even the square scrolls).

So it sounds like it's basically working, huh? I don't get why the tutorial
is showing a constant voltage instead of a wave like in the pdf, but if
it's working otherwise then at least I know I can learn on it.

David - I think I found the issue. The tutor wants an "AC adapter" and I'm using a DC adapter. It literally says in the PDF "most experiments won't work with a DC adapter"....

So...I feel dumb. Thanks for your help! My next goal (after getting the adapter) is to get the display to stop "scrolling"!

On Fri, Apr 1, 2022 at 11:17 AM, Pseudo wrote:

Yup, it shows a ripply, moving wave when i touch my finger to it...I can
never get it to be static though (even the square scrolls).

You might have the trigger coming from the wrong source. When you touch your finger to the probe tip you are coupling (capacitively?) to your house line power, so if you set the A TRIGGER SOURCE to LINE that should give you a steady trace. In general, however, you should have the TRIGGER SOURCE set to either NORM, or to CH 1 or CH 2, depending on which channel is taking the input signal (NORM takes the trigger from both channels in some way that I don't fully understand).

An even more general rule is that you can set the trigger controls to the top position for all controls (TRIG MODE = AUTO, COUPLING = AC, and SOURCE = NORM), then set the trigger level to mid-range, and that should give you a steady trace, assuming that your signal has adequate amplitude (or that you have selected the appropriate VOLTS/DIV range for the input channel).

These older scopes have a lot of interacting controls, and it is pretty easy to set them incorrectly (and there's no AUTO SETUP button, like there is with newer scopes, that will just do the right thing. The oldest Tek scopes, that I know of, with AUTO SETUP are the 2245A, 2247A and 2252, which are very nice scopes, but don't have the same feel as the 400-series). With even one control set incorrectly it can look like the scope is just not working, so it pays to double and triple check all your controls, and to have at least a basic understanding of what each control does (there's the rub).

-- Jeff Dutky

I posted on this very issue but never saw my post on the list.
?? There are a number of books on basic oscilloscope use available free on the web. I suspect they would be of more help than this "tutor". It looks like the OP is facing two learning curves: how to use the scope and how to use the "tutor". I say dump the "tutor". I still think that a good oscilloscope is the most valuable electronic tool one can have so its well worth the effort to learn about them and how to use them.
??? I hope I am not being moderated but have not received any notice of that.

--
Richard Knoppow
dickburk@...
WB6KBL

The classic introductory text (from Tek) on using an analog scope is the XYZs of Using a Scope. There are multiple versions, but the earliest one that I have ever seen is from 1981 and uses a 2213 as the stereotypical scope, which is similar enough to a 400-series scope that there should not be any confusion (the later editions of the text use scopes that are quite different from a 400-series analog scope, and the latest editions even changed the title to include both analog and digital scopes).

Here is a link to the 1981 (first?) edition of the text

-- Jeff Dutky