Logic analysis test kit vs oscilloscope

dyno

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Just wondering what would be better to have a logic test kit with a logic monitor, logic probe and digital pulser or an oscilloscope? I want to get one or the other, I see there are lots of oscilloscopes on ebay but most aren't complete and the shipping to canada is expensive and I know it would be cheaper to get the test kit. Just thought I would see what you guys thought.

Thanks
 
Just wondering what would be better to have a logic test kit with a logic monitor, logic probe and digital pulser or an oscilloscope? I want to get one or the other, I see there are lots of oscilloscopes on ebay but most aren't complete and the shipping to canada is expensive and I know it would be cheaper to get the test kit. Just thought I would see what you guys thought.

Thanks

The thing is that they are very different tools. Logic analysis just looks at digital operation - it can tell you a lot, but if the problem is of an analog nature (clock not square enough, voltages too high/low), it will either not see the problem, or it will see it as 'missing data', but with no clue what's really going on.

I'd go for the o-scope if I had to choose only one. That's because it can help you diagnose a larger range of problems that you are likely to face in fixing real boards. If you can find one and can afford it, digital scopes are awfully nice. They can't trigger as fast as analog scopes (and thus, there are things they can miss), but they can do all sorts of interesting triggering tricks that an analog scope can't.
 
Another vote for the oscilloscope.
It should be the first large expense item for electronics troubleshooting. In this case "large expense" is a couple hundred for a really nice used scope.

[EDIT]
Be sure to get a scope with X-Y mode.

Digital scopes can be really nice. I have one I use for special occasions. I like using the storage feature as a pseudo logic analyzer. And some of the automeasure features are nice. But my workhorse is the ubiquitous Tektronix 2445A - a nice solid analog scope with a CRT display. For people unfamiliar with the issues with digital scopes, an analog scope is often better. Easier to learn for your first scope and more importantly - easier to get correct measurements with. You can easily build a trigger box from simple common parts for most any triggering job that you'll encounter. I can watch movies on my 2445...if I really want to wave my geek card. Total added cost - about 10 bucks.

[EDIT again]
Many digital scopes have X-Y modes but they aren't very good. Because of the sampling nature of the machine, you get really lousy displays. Maybe unrecognizable. I saw an Agilent demo of one that was ok, but it's the only one that I've seen that had a decent "framerate" and the samples were fast enough to get a pretty good connect the dots picture. Still looked poor.
 
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Is it easy to learn how to use an oscilloscope? Also I found one on ebay which is a phillips but it doesn't have a probe, will any phillips probe work with it or does it have to be the exact one that came with scope?
 
Many digital scopes have X-Y modes but they aren't very good. Because of the sampling nature of the machine, you get really lousy displays. Maybe unrecognizable. I saw an Agilent demo of one that was ok, but it's the only one that I've seen that had a decent "framerate" and the samples were fast enough to get a pretty good connect the dots picture. Still looked poor.

Definitely. You have to be sure the digital scope has a sampling rate that's quite a bit higher (10x is usually OK, more is better) than the signals you want to measure. If you want to do an X-Y, then you probably need even more over-sampling to make sure you get a usable display.
 
I have both and use the logic probe far more than the oscilloscope. The probe I use has audio which makes it even easier to use.

I had 2 Mikie boards on the bench today. The first one had graphics corruption and the 2nd one no audio. The graphics corruption was easy to pinpoint with the probe: A0 and A10 were stuck high. This was quick and easy to tell with the audio tones.

I traced those pins back to 2 different 74LS174 chips. Those chips had inputs that were high so I traced them back to a common chip, a 74LS373. The chip had signals on the inputs but the outputs were stuck high. A quick replacement of that chip fixed the graphics corruption.

Now you can do that with a scope, but you'll be looking at pins, looking at the screen, looking at pins, looking at the screen, etc... until you find the problem. With the logic probe that has audio you just keep your eyes on the pins and ears to the sounds coming from the probe. Much faster. ;)

I'm still working on the audio problem. I have correct address/data/control signals on the sound chips, but will now break out the scope to see what is happening with the audio outputs from them.

RJ
 
If I had to pick just one, I'd go with the oscilloscope too. It's slightly more inconvenient to do digital logic stuff, as channelmanic explained, but will give you so much more information. (voltages, timing info, etc.) I would stick with an analog scope too; they're much cheaper, simpler to use and easier to learn on. We have some fancy digital scopes at work, and while they have some really nice features, there have been a few situations when I've needed to dig out the trusty old analog one.

Is it easy to learn how to use an oscilloscope? Also I found one on ebay which is a phillips but it doesn't have a probe, will any phillips probe work with it or does it have to be the exact one that came with scope?

It's relatively easy to learn, and there must be some good tutorials out there on the internets. All the scopes I've seen use standard BNC connectors for the probes, so no, you don't have to get a Philips one.
 
I think I misunderstood. A logic probe should be a very inexpensive purchase compared to a scope and getting both is reasonable. So I thought the OP was talking about a logic analyzer. Much more involved than the simple probe kit.

That's why I said "major purchase". The oscilloscope is the foundation of a EE workshop and should be the first "big" tool purchased. IMO.

Wood shop: hammer, drill, tablesaw...in that order.
Electrical shop: soldering iron, good multimeter, analog scope...other (endless) crap...in that order.

Everything else is gravy.
 
Thanks for all the info, I greatly appreciate it. I think I will try to pick up an oscilloscope, from everything you guys have said it seems to be the way to go. I just picked up a logic probe on ebay today for cheap so I will work with that, I have got my eye on an oscilloscope on ebay right now so I'll see how the bidding goes on it. Thanks for the info on the probes for the scope, I have found a few on ebay for a decent price. That said the scope I am watching is a 50MHZ and the probes I found are 100mhz and 60mhz so I assume they would work with this scope since they are a higher mhz?
 
Yep, you want the probes to be at least as fast as the scope. What type of scope are you looking at BTW? (make, model)
 
I don't think I've ever used a Philips scope, but that one seems decent. The operators manual is available for free download at The Boat Anchor Manual Archive
Mirror.


Ask the seller if it has onscreen measurement features. Or at least manual cursors.
 
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It doesn't have any of the features you mentioned, so is it worth still buying?

I have an old tektronix oscilloscope that I got on ebay for (IIRC) under $200 including shipping. It's a pretty basic 100MHZ scope and doesn't have any bells and whistles. Something like this is probably a good choice. All you really need it to do is display a wave form.
 
I have an old tektronix oscilloscope that I got on ebay for (IIRC) under $200 including shipping. It's a pretty basic 100MHZ scope and doesn't have any bells and whistles. Something like this is probably a good choice. All you really need it to do is display a wave form.
I'm a Tektronix fan myself. What model do you have Lindsey?

Regarding the Phillips, I think you'll be happy with it for a first scope once it's sitting on your bench. But it really depends on the final price. I hesitate to advise you there. Given the description, I think KLOV price would be somewhere around the current auction price. Expensive would be ~$100 considering you can get nice Teks for under $200, BIN.
 
I'm a Tektronix fan myself. What model do you have Lindsey?

Regarding the Phillips, I think you'll be happy with it for a first scope once it's sitting on your bench. But it really depends on the final price. I hesitate to advise you there. Given the description, I think KLOV price would be somewhere around the current auction price. Expensive would be ~$100 considering you can get nice Teks for under $200, BIN.

I have a 2235. It's 100MHZ and duel trace. It's a little old and flaky now but it works well for what I need. I'm thinking about getting a cheap handheld scope-meter and a logic analyzer this year.

Any suggestions on good logic analyzers anyone?
 
Have you guys hear of a circuit-test 2060 oscilloscope? I just cam across an ad on my local craigslist and the guy is asking $100 and it comes with 2 probes. I have tried to google it with not much luck. As for the philips do you mean $100 is sexpensive with shipping included or just $100 for the scope?
 
I spoke to the person selling the circuit-test scope and he said it works but besides that he doesn't know much about it. He said it was his father's who just past away and it was in his storage. He said he figures it is about 6-7 years old and that his dad bought it to work on a robotics project he was working on and he thinks his dad only used it when working on that project. I figure if his dad was working on a project like that he would know about electronics so he wouldn't buy a cheap oscilloscope. There is an electronics store up here that sells that brand but they don't have that specific model. It comes with 2 probes. He's asking $100 but is open to offers so I am thinking about it and maybe can get it for $80. I have tried to find the manual on it with no luck, the only models of circuit-test scopes I can find are the 2030 and the 2100. I would rather but it locally so I don't have to pay an arm and leg to have a scope shipped. What do you guys think?
 
Have you guys hear of a circuit-test 2060 oscilloscope? I just cam across an ad on my local craigslist and the guy is asking $100 and it comes with 2 probes. I have tried to google it with not much luck. As for the philips do you mean $100 is sexpensive with shipping included or just $100 for the scope?
Never heard of them. Personally, I would stick to Tektronix, HP/Agilent, or Lecroy, in that order. Tektronix basically invented the modern calibrated o'scope in the '40s. Their analog scopes are without equal. You should get one of those if you can. I recommend looking for something in the 24xx, 22xx, or 4xx series. Scopes I've used include 2445, 2235, 453, 465, and many others. The 465B is a workhorse, and very common. And very repairable. The 2445 has a particular IC that can go bad. It's basically unobtainium. But that is my favorite general purpose scope. Very easy to learn and use and very versatile.

HP 54000 series digitals are pretty good, but digital. I have a 54616 and has served me well, though I very rarely pull it out. Lecroys are very nice but they weigh more than your car. Probably. And they are digital (I think they *invented* digital scopes).

The also-rans, based on hearsay from colleagues and the web would be Phillips and B+K Precision. I really like the quality of Leader's video test gear and I would assume their o'scopes are of comparable quality. So consider them an also-ran as well, based purely on my speculation.

That gives you a good range of manufacturers as a starting point. If you can get the Phillips 3217 for $50 + shipping, buy it. As you become familiar with using it you can better decide if you want features that it doesn't provide.

No matter what you get, make sure you see photos of it working before you buy it. And don't buy a scope that you can't find an operating manual for.
 
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