is my scope buggered?

[m3vuv]

got this on my scope today trying to look at a 20mhz sinewave the timebase knob was fully clockwise(should be .1us,is what im seeing normal?

[ataradov]

Looks like it is jut not properly triggered. Although you could make better pictures.

And there is no need to create multiple topics for the same issue.

[m3vuv]

it was triggered fine,took the pic on my phone,i will dig my camera out.

[ataradov]

How do you know if it does not properly show nay signal? Have it been stable before? Have you tried to adjust the trigger level?

[m3vuv]

hope thats better,its the best pic i can get.

[m3vuv]

that was on auto trigger,ive tried it on manual trigger too,if i adjust the trigger wrong the trace dissapears.

[ataradov]

Can you make a clear picture of all the controls on the scope? There are many settings that  can cause this behavior.

Also, have you tried with lower frequencies?

[m3vuv]

the settings are 50mv div,ac coupled,see pic,seems fine until about 100khz then goes imposible to view properly.may have to rotate the pic.

[m3vuv]

just noticed the x10  was on turning it off just makes the display brighter but doesent alter the trace.

[tggzzz]

The answer is in your other thread on this topic. https://www.eevblog.com/forum/beginners/looking-at-a-waveform-on-a-scope/msg2714180/#msg2714180

If you can't manage to get a picture the right way up, I suspect you will find it difficult to get the scope controls in the right positions.

[ataradov]

From what I see you have 10 or 5 us/div set. It is not very clear from the picture, but 0.1 us/div setting is close to the bottom of the dial.

[maginnovision]

Can you push the center of time/div knob in and make sure time base is correct for frequency? Norm trig is good, level can be 0 if it's a sine wave. Some controls may be dicky so wiggle and turn a bit too.

[m3vuv]

the time div center knob is locked with the  outer knob its all the way to the right,ie clockwise as far as it will go it should be 1us,although the knob is in bad shape,im waiting for a new one to arrive from the usa nos,heres a pic of my dso with the same settings, the signal is 20mhz modulated at 600hz,both scopes are in the pics with the same signal.

[maginnovision]

You can't do any better than 1us? Can you knock it down to about 1MHz and strike the modulation? The signal is definitely there. Also how is your PC scope at 1ms/div(I'm assuming it's/div) which makes a 1kHz signal and it's the same signal?

[m3vuv]

i think ive sorted it,looks like the knob was positioned on the shaft wrong,at 20mhz now i see about 3 waveform peaks per div on either 1 or .1 tb settings,i cant see the dial very well as the plastic is yellow with age,anyway with it fully cw,does that seem about right now?,cheers Paul m3vuv.

[maginnovision]

Picture?

[m3vuv]

this is a 20mhz signal,no modulation at 20mv div and .1 i think or could be 1 us div horiz.

[ataradov]

There are exactly two periods per division. This is correct.

[m3vuv]

great,thanks for your help,have a good weekend,73 paul m3vuv.