r/AskElectronics • u/Poolscool • 2d ago
Just got gifted an old military Oscilloscope! Is it any good?
I’ve been searching for an oscilloscope for a long time now, and was recently just given one! Could anyone here tell me if it’s any good? I’m (obviously) not currently equipped to operate it, so could I get some advice on that as well? I’m looking to somehow connect it to an audio system (whether that be a guitar amp, record player, or just speakers), but I’ve got no idea how. What’re some good tips for starters?
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u/erutuferutuf 2d ago
any working scope are good scope!
just need to get a probe or two. and do some googling/youtubing and u should be good to go
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u/slapitlikitrubitdown 2d ago
The last time I came across one like this about 10 years ago. The power supply was shot and zero batteries were refurbished/available at the time. I sold it on eBay for 40 bucks.
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u/jbtronics 2d ago
Looks like a pretty capable analog oscilloscope (even with more advanced features like dual time base and a delay line). And 100 MHz bandwidth is enough for most hobbyist applications, and especially at audio range.
However it's still an analog oscilloscope, which by principle lacks advantages of modern digital storage oscilloscopes. But you can still do a lot of useful things using these analog scopes.
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u/SkipSingle 2d ago
The big advantage an analog scope has is that it does not have aliasing.
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u/Upset_Perspective_19 9h ago
I keep my old analog around for exactly this reason. The digital is nice, but that aliasing can really get you sometimes.
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u/tes_kitty 1d ago
It's nice to have both (analog and DSO) and if you get a 100 MHz scope for free, always take it.
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u/BlownUpCapacitor 2d ago
This is the military version of the Leader LBO 325.
Visit: https://archive.org/details/leader_LBO-325 for the manual. Some function might be different, but as far as I can see, looks nearly identical. I don't see any front panel differences.
Only differences might be the military version is easier to service, and or is built sturdier to meet military specs.
This is a 100MHz scope and seems to have many useful functions. Very good scope. Currently good for qualitative measurements. If you calibrate it, it's good for quantitative measurements.
Calibration of a scope will drift over time.
I suggest going to https://www.szynalski.com/tone-generator/ and get an aux-bnc adapter to play around with some waveforms.
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u/FuckingStickers 1d ago
What makes an oscilloscope "military"?
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u/BlownUpCapacitor 1d ago
The specifications it has such as durability, shock ratings, EMI resistance, supply voltage ratings (usually means it works on a fairly wide range of voltages and frequencies, up to 440Hz, common on aircraft), reliability, ease of serviceability (don't wanna have equipment you can't fix in the field), and so on.
It's just what the military wants. Usually they take an already existent model, and make it better so it meets the specifications the military has set for electronic test equipment.
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u/DickSplodin 1d ago
Things are very likely different now than they were back when this was used, but I don't think I've ever met another ET/AT that's ever serviced or T/s test equipment nowadays aside from calibration
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u/zx6rarcher 2d ago
Can confirm. This was one of the many oscopes we had in our shop (back shop avionics, component level repairs). It’s a good scope.
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u/Superb-Tea-3174 2d ago
Seems like a really nice 2-channel 100 MHz portable analog oscilloscope. Looks like Tektronix but I can’t figure out which one. Are there numbers on the back?
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u/woodbanger04 2d ago
It’s a pretty good scope for when it was made. And still applicable in many electronics today. Good score.👍
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u/StrugglesTheClown 2d ago
Ha I'm pretty sure my professor helped design this model. This is what we used in the labs.
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u/sitefall 2d ago
That's an old Leader LBO-326/A if I am not mistaken. I used to do I-level repair on these 20 years ago. If you have any issues send me a DM about it maybe I can help.
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u/Cheap-Chapter-5920 2d ago
I have this exact model in storage, used it for many years and it still works too. Trigger on these things can get a bit finicky, and if you're looking at something that's not constantly outputting it's super dim so you'll probably want a little hood (there's a groove on the bezel to hold it). Pretty good for audio and lower frequency RF stuff.
Also, I don't think they make analog scopes anymore, so the visual will be unique compared to modern scope. Like something that would be used for a movie prop.
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u/centstwo 2d ago
Make some janky cables and hook up a channel to the gold thing on the lower left of the control section marked Cal(ibrate) and look at that signal. That will give you some info on the state of the scope.
Enjoy.
You can also test batteries.
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u/Whatever-999999 1d ago
Nope! It's complete junk! Don't even plug it in, it'll burn your house down!
Tell you what, since I'll be a pal and give you $20 for it, just because I'm in a generous mood!
🤣 Just kidding, if it works then that's a great gift, wish someone would gift me an o-scope, I could use one!
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u/Some_Awesome_dude 2d ago
Looks like tektronics .
This so good to start with. If you keep using it and feel it's not up to par, you can invest in a good one.
If it fills your needs and you rarely use it, you didn't waste your money on expensive one
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u/LexxM3 2d ago
What makes it a “military” scope? EMP protection :-)?
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u/k-mcm 2d ago
Usually more bracing, more dust protection, and it can be quickly serviced. In the ones I've seen, the wires are bundled along one edge of each board so it all opens up like a book. They're easy to service so they last forever.
Lesser models may be stacks soldered to each other on all sides. You have to unwire each stack to get to the next. Fixing the sweep control switches can take more time than the scope is worth.
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u/flen_el_fouleni 2d ago
They also use MIL grade components inside which means a wider range for temperature and more chock proof
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u/Poolscool 2d ago
Old guy I got it from says the screen is so tiny because it was a portable one for military use. No idea if that’s accurate but it seems like it is.
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u/LexxM3 2d ago edited 2d ago
Portable, for its time, makes some sense. But I don’t see anything military about it. But perhaps internal specs were to some milspec at the time (wide temperature range, high humidity, airborne contaminant like sea air protection, high margins and high margin qualification testing).
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u/quewhatque 2d ago
There's a nice Cal test point (bottom left of the time/div knob) to see if the thing still works alright without spending too much effort.
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u/Odd_Put_1772 2d ago
That brings back wonderful memories! I sold mine about 25 years ago and it was old then! It’s still quite useful and I wish I had kept mine.
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u/KofFinland 1d ago edited 1d ago
Nice basic analog scope. A real workhorse that will serve you very well. Very similar to my first scope, almost exact copy. I still have it after 30 years. I saved it from a pile of junk at junkyard back then, totally working but thrown away, poor little thing.
You connect the probes (seen at top right of photo) to channel 1 and 2 BNC connectors. You can connect channel 1 to the "CAL" gold-colored U-loop at the bottom right next to CRT. It has 0.5V amplitude rectangular wave that you can view with the scope.
The biggest trick in using an oscilloscope is that the ground of the probes is connected together and to the safety ground of the grid. So you can't just connect even one ground anywhere in circuit, unless the circuit it floating. This is the important detail! Otherwise you can short-circuit stuff and cause havoc. It is often enough to keep the ground of channel 1 connected to circuit (like if you measure +5V supply, you connect ground to 0V and probe to +5V, then if you also measure +12V supply, you just connect probe of channel 2 to the +12V, and channel 2 gets 0V level from channel 1 ground which is directly connected to channel 2 ground. In the example, if you connected ground of channel 1 to 0V and ground of channel 2 to +12V, you could short-circuit the 12V supply! Never do that!
That is the no 1 thing to consider with oscilloscope!
Otherwise you pretty much select V/div for measurement range (div is division in CRT), like 1 V/div, and timebase like 1ms/div, and select DC "coupling" in selector lever under input BNC, and "coupling" source "ch 1" and adjust "trig. level" under it to get waveform visible and stable on CRT. You can try those with the CAL signal on channel 1.
Read the manual linked in another post!
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u/dvornik16 1d ago edited 1d ago
Turn it on. Check if you can see a stationary square wave on the cal output with correct timing and amplitude. If you can't, recycle it. Most of the equipment that old is junk by now. We have a graveyard of 30+ years old equipment, there is no value in them unless you have skills and time to refurbish them. Spend a few hundred bucks and get a decent modern scope.
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u/perduraadastra 1d ago
You can get a probe and hook it up to the calibration terminal. I'm guessing it outputs 5kHz. You can see if you get a square wave at that frequency.
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u/No_Lifeguard1743 8h ago
It’ll probably last longer than my osc that was made 5 years ago so there’s that..
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