O’scope

Let'sgoflying! said:
Toy, or indispensible garage/home lab/hangar tool?
www.fnirsi.com

FNIRSI 2C53P 3-in-1 Dual Channel Tablet Oscilloscope + Multimeter + Function Generator

Multimeter Multi meter Multi tester FNIRSI® 2C53P 3-in-1 Dual Channel Tablet Oscilloscope + Multimeter + Function Generator
www.fnirsi.com www.fnirsi.com
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Damn! Wish I'd bought this one you found instead of the pocket one I used for debugging my electrical issues recently (which was $60). I needed a portable device so I couldn't use my main scope.

For my house I have this one and it's worked really well for the last ~6 years: Rigol 4 Channel OScope
Portable. Reliable. Easy to use. All the features I need.

EDIT: Also I'd say it's classified as both a toy AND an indispensable tool. I've debugged a lot of little DIY electrical gadgets and collected information that would have been impossible with a regular multimeter. When you need it, you need it.
 
ArrowFlyer86 said:
Damn! Wish I'd bought this one you found instead of the pocket one I used for debugging my electrical issues recently (which was $60). I needed a portable device so I couldn't use my main scope.

For my house I have this one and it's worked really well for the last ~6 years: Rigol 4 Channel OScope
Portable. Reliable. Easy to use. All the features I need.
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That looks like a nice scope! If I ever get back to hamming I might pick one up.
 
The reviews say the accuracy isn't all that great.
 
Multimeter -- indispensable tool, no doubt. Scope -- for the vast majority of people I'd say occasionally useful toy. I don't recall ever taking my scope to the hangar, other than for debugging some bit of custom gear I was developing. Not saying it's useless, but my personal opinion is that you've got to be pretty deep in the weeds to need one.

As far as accuracy and calibration... I always assume that anything like this is a "general indication of what's going on" kind of thing, and not to be used for precise measurements. It might be dead on, might not be. If you really need something highly accurate, then you'll probably want to spend a little more.
 
And a 50 mhz bandwidth isn't much with gigahertz processors now a days..
 
Probably ok for a quick look tool, rather than indepth troubleshooting. For serious work, 100 mHz is minimum bandwidth I would want.
 
It will cost more, but a 150MHz scope can be handy for checking output and modulation depth on the COM transmitter.
 
Craig said:
Probably ok for a quick look tool, rather than indepth troubleshooting. For serious work, 100 mHz is minimum bandwidth I would want.
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I'm curious, what sort of stuff do you troubleshoot that demands higher bandwidth? My use case is as a hobbyist/amateur electrical debugger where my scope's capabilities are beyond what I would need. Wondering what applications require really heavy lifting? (I just haven't explored enough to know)
 
The usefulness of a scope depends on the activities one is engaging in. I’ve made my living working on developing and also servicing vehicle electronics for close to 30 years now and have found that a scope is mostly unnecessary in the hangar or garage at the level most professional mechanics and hobbyists are at.

A good multimeter is worth its weight in gold. I’d start with that instead.
 
ArrowFlyer86 said:
I'm curious, what sort of stuff do you troubleshoot that demands higher bandwidth? My use case is as a hobbyist/amateur electrical debugger where my scope's capabilities are beyond what I would need. Wondering what applications require really heavy lifting? (I just haven't explored enough to know)
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A low bandwidth scope will show you, in general terms, what's going on with a signal. For example, it will show you a sine wave, a square wave, whatever. Where the higher bandwidth comes in handy is when you need to see more detail -- is there overshoot or noise on the leading edge of the square wave? Is there trash or noise you can see on a 100 MHz scope that isn't obvious on a cheaper 10 or 50 MHz scope?

Again, probably not something you'll need unless you're pretty deep in the weeds, and by then you should know what you need.
 
ArrowFlyer86 said:
I'm curious, what sort of stuff do you troubleshoot that demands higher bandwidth? My use case is as a hobbyist/amateur electrical debugger where my scope's capabilities are beyond what I would need. Wondering what applications require really heavy lifting? (I just haven't explored enough to know)
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Radio work. I don't know about current digitally-tuned radios, but older stuff was superheterodyne, where an internally-generated frequency was mixed with the incoming radio frequency, and the resulting difference of a constant frequency was much easier to amplify. All the stages beyond the initial RF stages could be tuned to the intermediate frequency.

Transmitters, of course, generate a signal at the required radio frequency. For aircraft Com use, that's 108 to 118 MHz. And 760 divisions within that range.

My current 'scope is a Tektronix 453 dual-channel 50 MHz scope from around 1980. I paid $80 for it last year. It weighs about 30 pounds. At least it is free of vacuum tubes like my old 'scopes had. Worth maybe $2500 when new, over $14K in today's dollars. This is a pic off the 'net of what it looks like:

1719952743350.png
 
I have a 60MHz Hitachi. Not as sexy as the Tektronix, but adequate and I got it for nothing.
 
Dan Thomas said:
My current 'scope is a Tektronix 453 dual-channel 50 MHz scope from around 1980. I paid $80 for it last year. It weighs about 30 pounds. At least it is free of vacuum tubes like my old 'scopes had. Worth maybe $2500 when new, over $14K in today's dollars. This is a pic off the 'net of what it looks like:

View attachment 130889
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My 1980-ish four channel 150MHz Textronix cost about $3,100 when new. I retired it years ago, when replacing dried out electrolytic caps became too much trouble. It was indispensable for TTL repair, troubleshooting, and calibration.

Now get off my lawn.

:biggrin:
 
Fond memories of the Tek 475A with DM-44 that the Army had, and later used the same model in my first civvie job as a mainframe field service engineer. Pretty awesome scope, 250 MHz bandwidth. Good times.
 
I can beat all of you on age etc. A 600 KHz HP 130C from the 1960s w 0.2 mv/cm sensitivity for both X and Y axis, differential input, X time base of course. Never replaced any thing internally. And most importantly, no anti-aliasing filters needed. Diagnosed an over voltage sensor on our 172M. Still worked OK a few days ago.
 
Several already own one.
Give me some examples of how your Oscope was used in ordinary household/garage/hangar devices to diagnose a problem.
 
Dan Thomas said:
At least it is free of vacuum tubes like my old 'scopes had.

View attachment 130889
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Not quite. The 453 had vacuum tube HV rectifiers:

453 - TekWiki

w140.com w140.com

Then, of course, the display was a CRT or Cathode Ray Tube which was used until the mid 1990s.

I have a working 535A (circa 1960) at home but it is such a boat anchor (65 lbs) that I rarely use it; easier to borrow a more modern/compact unit from work.

1720013486136.png
 
nrpetersen said:
I can beat all of you on age etc. A 600 KHz HP 130C from the 1960s w 0.2 mv/cm sensitivity for both X and Y axis, differential input, X time base of course. Never replaced any thing internally. And most importantly, no anti-aliasing filters needed. Diagnosed an over voltage sensor on our 172M. Still worked OK a few days ago.
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I had a WW2 vintage 'scope that was old when I bought it for $50 in the early '70s. I used it working on old radios, and in the flight school I used it for tracing alternator noise. I left it at the flight school when I quit. It was so old that I can't find a picture of it on the 'net. All of the cabinet corners were very rounded, even around the front, a common fashion in the '30s and '40s. Soon after I bought it the HV rectifier tube burned out, a rare part even then, so I changed the tube socket to take an HV rectifier tube from an old TV, and rewired the socket as needed for the different pinout.

But I don't have it anymore, so I guess you win the prize as the owner of the oldest 'scope;)
 
flyingbrit said:
Not quite. The 453 had vacuum tube HV rectifiers:
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Serial numbers 44360 and up had silicon diode HV rectifiers, according to my manual for this 'scope. I opened it up and found no tubes at all, other than the CRT, of course. Tektronix made plenty of changes without changing the model number,
 
Tubes done right and applied conservatively, must age remarkably well. Never serviced my HP 130C in the ~35 (?) years I've had it, but it does take a couple of minutes to warm up if it has been sitting for a couple of months. To me the benefit of analog vs digital is WYSee is WYGet. Been burned a couple of times at work by aliasing in digitally monitoring stuff.
 
Let'sgoflying! said:
Several already own one.
Give me some examples of how your Oscope was used in ordinary household/garage/hangar devices to diagnose a problem.
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Last 6 Months.

Diagnosing alternator whine by examining the bus voltage trace and finding a bad diode. Diagnosing a no-start electronic ignition in my Jeep by finding a dirty square wave generated by a bad sensor. Looking at RS232 square wave to check presence of data output from an LRU.

Don't use it every day, but sure does come in handy.
 
Maybe 25 years ago found spikes on the Ford alternator output were tripping the over voltage sensor in our 172M. Can't recall the source (probably the alternator slip rings), but replaced alternator.

We used a handheld 1/2 hp electric motor and vee belt to drive the alternator in our hangar rather than run the engine. Much safer!
 
nrpetersen said:
We used a handheld 1/2 hp electric motor and vee belt to drive the alternator in our hangar rather than run the engine. Much safer!
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I had a tablesaw in the shop. I put it in front of the airplane and ran the belt between the saw's motor and alternator. Then I wore my headset while probing for the ground loop I knew was there somewhere, leaking alternator noise into the avionics. Found it, too. The airplane had a portable intercom, and someone had screwed its case to the console's aluminum frame, effectively grounding the headset jacks to the airframe at that point.

Headset jacks should only be grounded to a point on the radio rack. Otherwise stray alternator or strobe currents will find their way into places we don't want them.
 
:) I may have too many scopes. From an old 35 MHz dual trace Heathkit, to a 350 MHz Siglent digital.

They're pretty handy for a lot of analog and digital design work. They're very handy for reverse engineering things, like weird IR remote controls or proprietary low speed digital interfaces. A scope with a built in logic analyzer can be great at troubleshooting low speed digital circuits, but I don't know how many people besides hobbyists work on those anymore. I have one scope that can interface to a same brand signal generator to do AF to HF RF responses of circuits or equipment, and that's pretty cool.

I don't know how handy they are for repair of anything modern, because I don't know who but a hobbyist does board level repairs anymore. Design work, especially audio? Might be indispensable. Troubleshooting radio gear? I'd get an inexpensive VNA or spectrum analyzer w/ tracking generator and some bridges before a scope.
 
flyingbrit said:
Not quite. The 453 had vacuum tube HV rectifiers:

453 - TekWiki

w140.com w140.com

Then, of course, the display was a CRT or Cathode Ray Tube which was used until the mid 1990s.

I have a working 535A (circa 1960) at home but it is such a boat anchor (65 lbs) that I rarely use it; easier to borrow a more modern/compact unit from work.

View attachment 130912
Click to expand...
I had that exact same scope at home for a while. When I got it, it had the Type D differential plugin, but I got a CA shortly thereafter.

My first was a Heathkit O-9 (not triggered sweep).
 
I used a (very cheap-ass Chinese) oscilloscope to look at the signal output from the fuel flow transducer on my EI setup. Wanted to see whether the problem was in the box, or the transducer. It was the transducer, and easy to see - but I could not have gotten the kind of information I needed by watching the display on a DVM.
 
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