Test Equipment: Oscillocopes

[MarkE]

MarkE,

I think we should all just focus on getting Brian to the point where he can get stable, correctly triggered displays on his scope.

A bit of tilt is the least of his problems at this point.

In the last video of his scope in action, I wanted to turn off CH2, speed up the horizontal and adjust trigger level for a stable display.  Looks like he had one of the channels vert. sensitivity cranked up much higher than the other (or different probe factor), horizontal sweep way to slow, and that it was not triggering.  It has been some time since Brian has produced a video of a stable display, tilt or no tilt.

PW

His square waves were collapsing.  High pass had a shorter time constant than one half of each cycle.   Like you I thought that he had operation with the calibrator working.  I think he just needs to learn some basic skills:  read the manual and try things out with what he has on hand.

[Pirate88179]

What about that one trimpot he adjusted a little while back?  I would have thought that you needed another scope to tune those if calibration was off.

I believe he said he did not turn it much but, could that small adjustment cause any of this?  Maybe he could turn it back to about where it was?

Just wondering...most, if not all, of this is over my head.

I was blown away by TK's video of the weird shapes playing on his scope with the sound input.  How he inverted and made a mirror image of that logo is beyond me.  Unless, that is the way it is suppose to be?

Bill

ETA: https://www.youtube.com/watch?v=OxlCoKN4W7c

EEVblog made a similar video, and his logo is reversed also!  Probably supposed to be that way then....

PS  Dave said that Youscope was developed by a 15 year old kid a long time ago.  Holy crap!

Dave also runs it on his digital scope and..he really has to play with it to get rid of the fly back lines.  It does not look nearly as cool as it does on an analogue scope.

[TinselKoala]

It's interesting that Dave's Hameg analog scope shows the text backwards, like my 2213a does, but the Agilent shows it the right way around. I wonder why that is. I can't get mine to display the text frontwards by inverting the CH2 (y) channel, or by swapping L and R (this makes the text run up and down instead of across). So maybe he has a way to invert the CH1 (x) channel on the Agilent and this is the cause. It's a mystery to me for sure.

I'm also wondering if that's the best display that the Rigol could do. It's supposed to be able to do some huge number of waveform samples per second, I thought, so I expected the display to be better than that. Maybe he has the sample rate at some non-optimum setting for this file. Also it's rather surprising that he couldn't get audio output to speakers at the same time he was scoping the file from the output jack. I have no problem doing this with my desktop system. I suppose this depends on the headphone jack arrangement. Maybe his HP jack turns off the speakers; my front panel HP jack doesn't have to do that if I don't want it to.

[Brian516]

OK, I am taking a break from cleaning this nasty arse desktop PC to format and load Ubuntu on for the lab stuff, and all that... came back over to check the thread and 

I made a list of things to try, and I am going to start with checking the ground for resistance/continuity,
then get it warmed up, set XY no input, set to ground, check focus, and tweak astig if necessary (no improvement, back to initial setting)
(start vid)
then do the LINE test using my PCFG w same sq wave settings as cal loop w/ 1 channel only.
then I'm going to put CH1 on cal loop, upper half to start, then add in the PCFG CH2 bottom half w/same freq etc (triggering off cal loop)
anything else?

Let me know if you think that the +55V rail that I adjusted per manual instruction (first part first section of calibration, I believe it is) is causing me these issues, or if you want me to set it back to 55.14V anyway and check.  'twould be easy enough if it may solve my issues.

so from my understanding of connections thus far, If my laptop had a ground on it's plug and a proper connection from charger to PC, I technically don't need to have the "reference" clip connected, is that right?  If so, that would mean a laptop PC should be just fine for using as a FG when unplugged, even, as long as I have a good connection to the laptop's 'chassis' ground (or ground on HP jack collar, same thing) w/ the reference clip.

I will check back before I start the vid once I turn my laptop back on. Can't remove the battery for this test though, or I would do that, too, so there would be no power source other than the PC clock button cell on the MB.

You know, I vaguely remember actually getting fairly good looking square/triangle/sawtooth waveforms from the PCFG the first time I got the PCFG working.....  I don't know what could have changed from then to now.. other than me. so I shall try this again from sq 1..

[Pirate88179]

It's interesting that Dave's Hameg analog scope shows the text backwards, like my 2213a does, but the Agilent shows it the right way around. I wonder why that is. I can't get mine to display the text frontwards by inverting the CH2 (y) channel, or by swapping L and R (this makes the text run up and down instead of across). So maybe he has a way to invert the CH1 (x) channel on the Agilent and this is the cause. It's a mystery to me for sure.

I'm also wondering if that's the best display that the Rigol could do. It's supposed to be able to do some huge number of waveform samples per second, I thought, so I expected the display to be better than that. Maybe he has the sample rate at some non-optimum setting for this file. Also it's rather surprising that he couldn't get audio output to speakers at the same time he was scoping the file from the output jack. I have no problem doing this with my desktop system. I suppose this depends on the headphone jack arrangement. Maybe his HP jack turns off the speakers; my front panel HP jack doesn't have to do that if I don't want it to.

TK:

I am glad you noticed that the lettering was correct on Dave's digital scope.  I thought I saw that as well.  My new pc, if using the headphone jack on the front, disables the speakers of which I am running a total of 11 including a sub.  (All of my speakers except one pair have their own amps including a 100 watt/channel driving my 12" Cerwin Vegas in the living room.)  I can take or tap into one of the line outs on the back and still hear the music.

What the hell is a flac file?  I mean, I know what it is...I looked it up...but have not downloaded any program to open such a file.  I have used some of the choices given in the past and, my problem is, they take over every audio file and you have to use their program to play anything.  Should I just convert the youscope file to mp3?

I thought you would enjoy Dave's video on this.  He really had to manipulate that digital scope to get it to look right, and it still did not look as good, in my opinion, as the older model, ha ha.

Bill