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New Oscilloscope Day! (Now what?)

#21
i use it to figure out why something isn't working
case in point: purchased a dirt simple clean boost pedal for cheap because it wasn't working. removed and tested all components and couldn't figure out why it didn't work. hook up 1khz signal from my tek453 to the input and see where the signal stops. turns out an op amp biasing resistor, which should've been 470k was 470 ohms. somebody pulled the wrong resistor from the bin (easy to do with those blue metal films) and even i missed that my autoranging meter told me it was .470k instead of 470M (here's where an older style meter would've helped too)
quite useful
 
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#22
What do you all find you most frequently use an oscilloscope for?[/QUOTE]

Congrats. I got one a a few years ago to use with my model railroad. Basically there are computer chips in the engine controlled by a command station ie computer over the track and track wires which is basically a CAT5 network. I use it to look at the wave form and make sure it looks proper when I am diagnosing a problem, doesn't see a lot of use but very helpful when needed. I am a paper pusher by day and have no other use for it. Looking forward to seeing how to use it in music. Mine is portable.
 
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#23
Passinwind said:
Troubleshooting and measuring pretty much everything, and testing every new DIY build. A big part of that is looking at out-of-band performance, i.e. parasitic oscillation and general behavior at higher frequencies than we can hear. This often translates to stability, and not blowing stuff up is always a bonus.

I have a 90s vintage digital Tek 4 channel scope that I was given, which needs a substantial rebuild due to the infamous "bad caps" syndrome. I will probably never get around to that and would consider giving it away to someone with the requisite experience to replace 85 or so SMD parts, and the willingness to pay shipping cost or come pick it up. It's a big nasty job and it may easily still not work after that since it's been sitting for so long. If anyone feels brave enough to take this on they can PM me. I'd hate to take it to Staples for destructive recycling, but that's the other most likely outcome. My 35 year old analog Hitachi scope still does what I need it to do and I just have way too many other rabbit holes going on at the moment.
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Which Hitachi do you have? I bought a V1065 new back in the late 1980s, and it still works perfect, too.
 
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#25
byacey said:
Which Hitachi do you have? I bought a V1065 new back in the late 1980s, and it still works perfect, too.
Click to expand...

V302F. I could use to to clean or replace the volts/div selector on channel one, but all but one range are still fine and it's hasn't been a big priority. I bought it brand new in 1984 IIRC. Before that I had a humongous Tek 500 series dual timebase unit with the shop cart.
 
#28
tlite said:
10-4 and thank you! This scope has selectable 1X/10X probes. I'm not opposed to reading and tutorials at all- though admittedly I will default to hands-on learning when possible. I'm Googling this stuff, but any sites or tutorials you recommend?
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I took a class on test equipment that specifically covered how to use oscilloscopes. This was over 30 years ago though. I suggest Googling "oscilloscope tutorial" and you will find a bunch of possible videos and articles.

The document @byacey linked is pretty good. Also read the manuals for your O'scope and probes as they will list the max voltages your equipment can handle. The tricky part is the max voltage may change depending upon how you have the probe set. So you need to memorize the specs, know circuit conditions where you are probing, and be mindful of what you are doing so you can adjust the probe accordingly.

I found this article titled "Select the Right Oscilloscope Probe for Your Application." Select the Right Oscilloscope Probe for Your Application - National Instruments It shows four 10:1 probes and lists their max voltage. Two are rated up to 300V and two are only rated for 60V. FYI Many of my tube preamps have circuits that exceed 300V and I have one tube amp that has 711V on the HT supply, so I would need a suitable 100:1 probe.

I Googled the two 300V probes and the prices were listed as $266 and $278, so you probably wouldn't want to damage one by mindlessly exposing it to more than 300V.

Many cheap digital multimeters have a working voltage of 600V. So you could probe with a multi-meter to see what you are dealing with before you go poking around with the O'scope.
 
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#29
Wasnex said:
I took a class on test equipment that specifically covered how to use oscilloscopes. This was over 30 years ago though. I suggest Googling "oscilloscope tutorial" and you will find a bunch of possible videos and articles.

The document @byacey linked is pretty good. Also read the manuals for your O'scope and probes as they will list the max voltages your equipment can handle. The tricky part is the max voltage may change depending upon how you have the probe set. So you need to memorize the specs, know circuit conditions where you are probing, and be mindful of what you are doing so you can adjust the probe accordingly.

I found this article titled "Select the Right Oscilloscope Probe for Your Application." Select the Right Oscilloscope Probe for Your Application - National Instruments It shows four 10:1 probes and lists their max voltage. Two are rated up to 300V and two are only rated for 60V. FYI Many of my tube preamps have circuits that exceed 300V and I have one tube amp that has 711V on the HT supply, so I would need a suitable 100:1 probe.

I Googled the two 300V probes and the prices were listed as $266 and $278, so you probably wouldn't want to damage one by mindlessly exposing it to more than 300V.

Many cheap digital multimeters have a working voltage of 600V. So you could probe with a multi-meter to see what you are dealing with before you go poking around with the O'scope.
Click to expand...
It's also wise to have an AC isolation transformer when working on hot chassis and non-ground referenced measurements like bridged amplifier outputs.
 
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#30
Bass4Gsus said:
What do you all find you most frequently use an oscilloscope for?
Click to expand...

Congrats. I got one a a few years ago to use with my model railroad. Basically there are computer chips in the engine controlled by a command station ie computer over the track and track wires which is basically a CAT5 network. I use it to look at the wave form and make sure it looks proper when I am diagnosing a problem, doesn't see a lot of use but very helpful when needed. I am a paper pusher by day and have no other use for it. Looking forward to seeing how to use it in music. Mine is portable.[/QUOTE]


When I was tech, the O'scope was pretty much my favorite piece of test equipment. You can use it for taking DC measurements and AC measurements, although it's not necessarily the best tool for DC measurments. Mostly I used it to probe the AC signal path in order to isolate where in the circuit problems occurred. I also used a multimeter quite a bit, but more for measuring components, voltage checks, and calibration than troubleshooting. The O'scope usually got me in the ballpark the multimeter was used to narrow the problem down to the specific component.

Another piece of equipment I really found useful was a spectrum analyzer, but unfortunately most of the shops I worked in did not own one. I was a radio tech and there were lot's of situations where I wanted access to a spectrum analyzer. I doubt a spectrum analyzer would be as useful for working on amps.
 
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#32
AndyPanda said:
IThere is a hack where you can turn it into the much more expensive one (higher bandwidth) since all the components are the same, you just need to trick it into accepting the firmware for the higher end model.
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Looks like I lucked out- I watched this video after reading your post and it explains that if you can set the time divisions down to 2 ns that it has been "pre-hacked" at the factory to be able to read 200Hz. And, mine goes to 2ns! Not sure why I need that range, but sounds like a good thing!
 
#33
tlite said:
Looks like I lucked out- I watched this video after reading your post and it explains that if you can set the time divisions down to 2 ns that it has been "pre-hacked" at the factory to be able to read 200Hz. And, mine goes to 2ns! Not sure why I need that range, but sounds like a good thing!
Click to expand...
I don't think the guy in that video knows what he's talking about. Just because he is able to set the time base to 2ns doesn't mean the scope is accurate to 200mhz. There are two capacitors that need to be physically de-soldered from the circuit board (they cutoff everything above 70mhz) and you would need to buy new probes that can handle 200mhz.

The test he should have done is to feed a 200mhz signal to the scope and show a clean trace of the correct amplitude. I'm sure if you had a signal generator that could sweep up that high you would see the amplitude drop off drastically above 70mhz.
 
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