# [SOLVED] Oscilloscope



## jrrdw (Jun 26, 2010)

I'm getting into PCB repair and I'm wondering if a oscilloscope would be worth the investment? I've been floating pins to removing components completely to test them. How would a oscilloscope help me out? Can I test components while still on the PC board and get a accurate measurement with a oscilloscope?


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## octaneman (May 13, 2009)

*Re: Oscilloscope*

Hi jrrdw


Getting yourself an oscilloscope is an absolute must in the electronics trade, it is an indispensable tool for troubleshooting pcb's. Whether you are into home electronics repair or prototyping new ideas, having an oscilloscope will help you diagnose component problems quickly an efficiently with a high degree of accuracy when the board is powered up. 

If you are looking for a scope with a decent price and has allot of functionality here's a great place to start:

Below 100 MHz: Saelig Online Store


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## jrrdw (Jun 26, 2010)

*Re: Oscilloscope*

These things are costly. I've been looking at them on Ebay, but they are mostly out of production models. Taking a chance there and for some reason they don't seem to want to sell the probes with them. Thanks for the link.


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## Done_Fishin (Oct 10, 2006)

*Re: Oscilloscope*

accuracy is dependant upon make & model .. normally around 3% but remember that thr frequency response drops up to 3dB as it approaches the bandwith .. ie a 20MHz scope measuring a 20MHz frequency might only indicate half the voltage waveform .. 

you'd need to know what you should be seeing in order to know whether it might help plus if you got a model with a component test option .. it will (with experience) assist in diagnosing faulty capacitors, diodes, transistors etc .. 

having said that I have been using experience & a multimeter these last 4 years to make repairs .. invaluable yes .. indispensable is debatable .. they are really handy when you have some indication of what to expect .. and they can be just as confusing if you do know what to expect or don't ..


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## jrrdw (Jun 26, 2010)

*Re: Oscilloscope*



Done_Fishin said:


> accuracy is dependant upon make & model .. normally around 3% but remember that thr frequency response drops up to 3dB as it approaches the bandwith .. ie a 20MHz scope measuring a 20MHz frequency might only indicate half the voltage waveform ..
> 
> you'd need to know what you should be seeing in order to know whether it might help plus if you got a model with a component test option .. it will (with experience) assist in diagnosing faulty capacitors, diodes, transistors etc ..
> 
> having said that I have been using experience & a multimeter these last 4 years to make repairs .. invaluable yes .. indispensable is debatable .. they are really handy when you have some indication of what to expect .. and they can be just as confusing if you do know what to expect or don't ..


I'm working on a large signal board with a lot of parts. It's during my spare time but still takes a long time removing 1 component at a time. Plus taking a chance on messing up the board. This particular PCB cost $425.00 + shipping brand new. There's got to be a better way! :4-dontkno (like buy a better tester)

Done_fishing, do you do a lot of this kind of work?


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## Done_Fishin (Oct 10, 2006)

*Re: Oscilloscope*

been using a scope for 40 years ... due to experience don't use one as often as I used to .. I use my brain for analysis & diagnosis of problems .. a component tester is very helpful


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## jrrdw (Jun 26, 2010)

*Re: Oscilloscope*

Another question: Do the MHz rating of the probes have to match the MHz rating of the oscilloscope? Example: If I have a oscilloscope with a 15MHz rating can I use a 100MHz rated probe with it.


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## Done_Fishin (Oct 10, 2006)

*Re: Oscilloscope*



jrrdw said:


> If I have a oscilloscope with a 15MHz rating can I use a 100MHz rated probe with it.


yes but not the other way around .. the frequency rating defines the 3db point ie when the signal is attenuated by half due to the "response" of the cable, connectors and tip. 
you should also tune the probes for best response using the calibration function of the scope and adjusters on the probe.


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## jrrdw (Jun 26, 2010)

*Re: Oscilloscope*

Thanks for the information, it has helped a lot.


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## Done_Fishin (Oct 10, 2006)

any time! :wave:


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