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Oscilloscope question

kaos513

Sr. Member
Apr 10, 2014
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Putnam county,NY
I halve. 100 MHz scope and a 20mhz scope I was an alignment on a cobra 148 gtl my 100mhz scope couldn’t get a signal but my 20mhz scope managed to see it with any ideas what could be wrong ? Thanks
 

I halve. 100 MHz scope and a 20mhz scope I was an alignment on a cobra 148 gtl my 100mhz scope couldn’t get a signal but my 20mhz scope managed to see it with any ideas what could be wrong ? Thanks
If your 100 MHz 'scope is dual channel, make sure you have the proper channel selected.. Do you see a trace at all?
 
There is usually a control called "BEAM" or "LOCATE" or POSITION press it - see if it will bring up both traces.

upload_2020-4-30_14-54-19.png
You may have inadvertently set brightness ot centering on one on one killing the other or moving it off.

IF you have Trigger on, set it to Internal and also check if AC or DC bias is set - else it may be looking to "trigger" using external and remember to check DC setting you may set set your position to DC so it looks for Offsets
 
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I would think there would be an input protection on the scope - you'd have to look at the owners manual (operation) and see if there is a fused protection...

Why? Because if you were looking for AF-signal on a DC line - you can accidently set the input to DC, see the offset push up the beam off the screen - as you are scrambling to find where your trace is, meanwhile it's smoking up the buffer resistor shunt too...
 
I would think the would have better input protection but then the scope I got is umpteenth handmedown and in order to get it to work again had to replace a set of resistors from the input BNC on both X and Y.

So if you lost your signals - it simply may mean a range switch for your input level may be ok, it's the "multiplier" resistor that the range goes or "calibrates" to - is burnt out.

IF you still have other ranges you can see, use and Calibrate on - you still have a scope. Relax, you just need to replace the resistor "shunt" used for that range...

These things are pretty tough - delicate - but tough.
 

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