Test Equipment: Oscillocopes

[picowatt]

PW,

I've edited my last post a little since you last read it.   
I don't know what exactly the issue was, but for some reason it seemed to be a software issue with that Soundcard Scope program, since VA's FG is running fine, and I have the reference clip (ground clip) hooked to the 'ground' sleeve of the 3.5mm (well, the wire I ran off of a jack).
I wanted to test it with some simple FG waveforms first. That way I know what I am supposed to see, and know if the scope shows the correct trace or not.
Now that I have it working, and am seeing the correct traces, I will run some music into it while listening tomorrow, and play around some more with the PC FG's I have.  Maybe I'll even figure out what was causing the issues with using Soundcard Scope.

I did notice that the trace drops about 2/3 amplitude when I plug the HPs in. With the output volume at 15% I'm reading about 225mV w/o HPs, and about 80mV with HPs.

Brian

Brian,

Glad your getting it sorted out.  The levels you are measuring sound about right, including the noted level drop when the HP's are connected.

Connect the L&R output to the scope channels 1&2.

Grab a tune off of youtube and play some music...

Don't forget to play with the X-Y mode as TK suggested at some point as well.

PW

[Brian516]

Greetings everyone,

I'm back at it with this scope today finally, and I'm running into some new issues.
I'm going to make a video to show as much as I can here in a few minutes, but I am first going to give a brief description of the issues.
It seems to have to do with the triggering for the most part.

After having it powered on for around 15 or 20 minutes, the trace started to get fairly unstable. It would 'jitter' around a lot, and had a horizontal line which seemed to 'start' from the right side and 'pull' the trace at the peripheral of the line. (I had two channels in, one top one bottom, line occurring on both traces).

At first, in order to get a stable trace on a different time/div setting from .5ms, I had to change from ALT to CHOP and put the trigger coupling to HF REJECT on both channels. It did this in both AUTO and NORMAL trigger modes.

-Among other issues that it is having which I will do my best to show in the video I'm about to make.

Brian

I don't know what kind of issues I may be having with my PC output again, but I went back to step 1 and hooked both channels to the calibrator loop on the scope and everything seems to be OK.
However:
In order to get a stable trace outside of the .5ms setting, I had to switch 'A trig coupling' to "HF Reject".. my settings are as follows:
[Input side]  X10 probes; 20m/div; DC input coupling; CHOP
[Trigger side] Mode: AUTO; Source: NORM; Levels=0; Slope +; holdoff: Normal; Horiz: A.

If you are going to see what all this is looking like on your scope, put it on AC or DC trigger coupling (doesn't matter which on mine) and start at .5ms. Switch out of .5ms and see if you have to put it in HF Reject mode to get a stable trace.
On the ALT vertical setting, I have to have the trigger coupling on LF Reject for anything outside of .5ms, and DC trigger coupling on .5ms.

Ok, now there are some seriously weird things happening with this scope and the settings. Actual scope issues video time...

[Brian516]

https://www.youtube.com/watch?v=gEJV-UOGxqw&feature=youtu.be

[MileHigh]

Brian:

It looks like there is nothing wrong with your scope.  The beam is disappearing when you are not triggered.  I suggest that you watch most of the clips from this link:

https://www.youtube.com/user/AllAmericanFiveRadio/search?query=oscilloscope

You have to adjust the trigger level to get a stable waveform.  It's the most important adjustment for getting a stable waveform.

There is nothing to clean in your scope.  Over the next week or two you need to learn how to use your scope, then perhaps consider working on it.  However, it looks like the scope is fine and there is nothing for you to do to it.

MileHigh

[Brian516]

When I was attempting to clean up the waveform/stabilize it and would change the trigger Level adjustment, nothing at all would happen.
I will try again, though. Just to be positive.

I will watch the vids on that page that have to do with the O-scope, plus some others look pretty interesting also.

This is obviously after I learn how to use my equipment, but I was thinking a great place to start experimenting might be with tank circuits and crystal radios, and that channel fits right in there.

Brian