noob and oscilloscope

Thread Starter

v1x2w3

Joined Jan 20, 2007
54
In any case, if you don't already have a good DMM, an LCR meter of some sort, and some to inject and detect signals (this lat one, the generator and tracer are going to be more important than a scope in audio repair work) and buying them would mean not buying the better scope, buy them, @MrChips is right.


I hope Klein MM400 qualifies as the DMM. LCR meter and Signal Generator are the next tools needed then. The tracer I hadn't heard of before MrChips brought it up.
 

MisterBill2

Joined Jan 23, 2018
27,587
"Good" probes start with a reliable connection with the test lead to the meter. Then next is the probe point which is able to make a reliable connection with the surface being contacted. I have suffered with probes that seem to have an invisible insulating surface on all the metal except for the front of the tip.
In addition, a good probe does not need to be re-tightened frequently, and the insulated handle portion should be easy to grip in a stable manner.. Also, the test lead should be flexible enough to not interfere with using the probe. That means not stiff.
So there are a lot of "good" probes around, as well as some less good ones.

Oscilloscope probes are an entirely different subject.

And thanks for the PDF, that is a complete receiver and amplifier, mine must have been a different model it was only an amplifier, no receiver. That was quite a few years ago.
 

Ya’akov

Joined Jan 27, 2019
10,243
I am sure the Klein is fine. A common and very effective method of troubleshooting audio circuits is injecting an audio signal into one stage and tracing it to another. You can use a purpose built set of injector/tracer or a general purpose signal generator, and an amp like @MrChips mentioned. You can also build your own injectior easily. Lots of schematics and how-tos out there. Might be a fun project.
 

MaxHeadRoom

Joined Jul 18, 2013
30,680
The scope probe ground will be tied to your electrical systems earth ground througet the oulet’s third pin. In some power circuits this means there will be a high potential between your scope at what you are probing. This can be very bad.
The portable/hand held DSO doesn't apply tho'
 

Ya’akov

Joined Jan 27, 2019
10,243
The portable/hand held DSO doesn't apply tho'
As would be suggested by the lack of a mains earth ground, but good to make that point specifically since battery powered scopes are nice for cases where you aren't sure if, or do know for sure you are going to have trouble.
 

Thread Starter

v1x2w3

Joined Jan 20, 2007
54

Thread Starter

v1x2w3

Joined Jan 20, 2007
54
It suddenly occurred to me that a warning for the future is appropriate:

Before attaching your oscilloscope’s probe (tip or ground) to any powered circuit be sure you know what you are connecting to.

The scope probe ground will be tied to your electrical systems earth ground througet the oulet’s third pin. In some power circuits this means there will be a high potential between your scope at what you are probing. This can be very bad.

It isn’t something you have to worry about with just a little forethought and study.

Here is a good video that explains the whole thing, worth watching:

Thanks for this. Although I read previously that I can't be as cavalier with oscilloscope probes as I am with a DMM, it is something I need to drill into my thick skull!
 

Ya’akov

Joined Jan 27, 2019
10,243
Am I missing something? This seems to do ESR and more for $30:

https://www.amazon.com/gp/product/B01MS1FOYM/ref=ask_ql_qh_dp_hza


I had written this before I got excited about the above product :)

Tough to beat this price!

https://www.amazon.com/gp/product/B078X9PVX3/ref=ask_ql_qh_dp_hza

User review says this does not allow duty cycle adjustment. Is adjustable duty cycle desireable?

https://www.amazon.com/1HZ-500KHZ-Functional-Generator-Frequency-Counter/dp/B07WFT3679/ref=sr_1_13?crid=3GJZKD6ZBQ8L3&keywords=Digital+DDS+Function+Generator&qid=1643899746&sprefix=digital+dds+function+generator,aps,105&sr=8-13
This is the one I have, and it is good for a lot of things, like quick checks when sorting components and go-no go checks, but it doesn't really replace a proper LCR meter. But, I think ultimately every electronics hobbyist should own one for what it can do.
 

ag-123

Joined Apr 28, 2017
294
I think DSOs are cheaper these days, especially the USB types - i.e. no lcd screens.
Just that for cheap DSO, 2 of those things likely suffer.
1 sample rates cheap ones maybe like few msamples per sec at most
The other thing that'd suffer is the storage memory, microcontroller based ones could have like a few k bytes (not Megs) of storage.
the 'good' ones many have upwards of 100 Msamples per sec, but they are expensive, with probes, lcd and all.
 

Ya’akov

Joined Jan 27, 2019
10,243
Those same items are available from Ali Express for less without having to pay the middleman's price markup. IF you are willing to wait several weeks for delivery!

For DSO from AliX, quite handy and surprisingly good for what it is albeit only 1 channel...
DSO150 Digital Oscilloscope full assembled with P6020 BNC standard probe|dso oscilloscope|probe oscilloscopebnc oscilloscope - AliExpress
View attachment 259540
I have a tiny version of this, caseless with a smaller display, but I think it's the same hardware. It came with just a pair of alligator clips so I bought a probe (with the MCX connector so the massive BNC to MCX adapter wasn't needed). It's part of my "tiny toolkit" for travel. I am still working on it, I want a better DMM, and actually a better scope.

1643907802991.png.tempImageKihx0y.gif
tempImagevTtqKA.gif
 

Thread Starter

v1x2w3

Joined Jan 20, 2007
54
This is the one I have, and it is good for a lot of things, like quick checks when sorting components and go-no go checks, but it doesn't really replace a proper LCR meter. But, I think ultimately every electronics hobbyist should own one for what it can do.
ok I'll order one of those. I am confused about what constitutes a proper LCR meter?

Here's a generic meter but I am missing how it differs from the one you linked:
https://www.amazon.com/gp/product/B00GYSFOM6/ref=ox_sc_act_title_2?smid=A3H7GPL9U124TQ&psc=1
 

Ya’akov

Joined Jan 27, 2019
10,243
ok I'll order one of those. I am confused about what constitutes a proper LCR meter?

Here's a generic meter but I am missing how it differs from the one you linked:
https://www.amazon.com/gp/product/B00GYSFOM6/ref=ox_sc_act_title_2?smid=A3H7GPL9U124TQ&psc=1
The origin of this type of component tester is this: https://www.electronicsweekly.com/b...r-simple-electronic-component-tester-2021-07/

But a proper LCR meter has different functions, is more accurate, and is able to deal with higher voltage components safely.

Randomly, this sort of thing: https://www.amazon.com/DER-EE-ELECTRICAL-INSTRUMENT-CECOMINOD066433/dp/B00S298KJO/

1643908890683.png
 

Ya’akov

Joined Jan 27, 2019
10,243
This guy shows problems with the XX2206 function generators:

I was ready to go with one of the XX2206 kits before seeing this. (Or, do I car about the issues shown?)

ebay has a bunch of used function generators under $100.

In addition to the above, I wonder about this one:

https://www.ebay.com/itm/384262268075?hash=item5977d0e4ab:g:HvwAAOSwxj5f3Av-
I would consider something like this before that:

https://www.ebay.com/itm/304343796147

It's a much better device and unlike the CRO, it's not a minefield of controls. (Though you do have to learn it.)
 

MaxHeadRoom

Joined Jul 18, 2013
30,680
The only issue I have with this kind of equipment, they mostly originate from China so the manuals etc. are in Chinglish which often takes some deciphering! o_O
 
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