What to look for when buying an oscilloscope?

ReWrite

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I see everything from $20-$1500 locally. Single channel to 4. 15Mhz to 1000Mhz. Dual trace, not dual trace. Hitachi, HP, BK, Snap-On, etc etc. And as they say, it's all Greek to me.

I have a bunch of semi-working JAMMA games, and I think it'd be interesting to learn to fix them. But I don't have a clue what to look for in this fancy new tool.

What do I need?
What do I not necessarily need but will appreciate having?
What's completely overkill for the job at hand?
Does it truly matter whether going digital or analog?
 
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Of course, if you do not know how to use one, you will be lost no matter what you buy.

Well I certainly can't learn without one. Or with one that won't do what I need it to :p.

So it works well for Donkey Kong. What about more complex games from a decade and a half later? Would that be sufficient for those? Is that model overkill for what you're using it for, or is it just the bare minimum? Somewhere in between? So many questions left unanswered.

There are a dozen threads with recommendations, but seemingly little information on what is actually important to look for. Just "get this" and "I like this one".

The 460A gets brought up a lot. It's 4-channel, digital, 400mhz and $30 cheaper. Why not that one over the 2235?
 
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The minimum requirements (as well as any optional features) depend on what you're working on, and how deep into it you're going.

For example, if you're working on vector games, you want an analog scope with 2 channels and XY mode, for displaying vector graphics (which don't look as good on a digital scope). But you won't use XY with JAMMA games.

One channel is enough for a majority of general debugging (as much of the time you just want to see if a signal is present, and if it looks ok). But there may be times when you want to see two channels, when you want to compare timings of two different signals. Very rarely do I personally need more than two for arcade use, but that's not to say it can't happen. I have four channels on both of my scopes, but never really use more than two.

As for bandwidth, I can't speak for what speeds the newest games run at, but for 80's stuff you'd want at least 50 MHz, and if you can find it affordably, go for 100 MHz or more. Again, it comes down to having the extra power for those times when you might need it. The more bandwidth you have, the more clearly you'll be able to see signals, but how much you need, and how clearly you need to be able to see any given signal is going to vary, depending on the situation. So it's better to have too much than too little.

If you want a decent, affordable, modern digital scope, a lot of folks have the Rigols. I've been considering picking one up myself, for the digital features. I'm not up on which is the latest model, but there's one from a while back that was hackable, to expand the bandwidth. Digital scopes have bells and whistles like automated measurements and cursors that can be useful sometimes. See here:

https://www.youtube.com/watch?v=LnhXfVYWYXE


But in the end, they're all tools. And when you're troubleshooting, you never know when a better tool or more capability might come in handy, so it's a matter of having as much in our toolbox as you can reasonably afford (and knowing how to use it, which there are many good tutorials for on youtube).
 
I have an analog scope for vector/analog work. TEK 2465B

I have a digital scope for raster/digital work. RIGOL DS1054z

Here's the digi scope being used for analog work, not bad but not the same either. :) Lots of functions though ...
http://forums.arcade-museum.com/showthread.php?t=366866

I can recommend both.

However, a scope is only really one of many pieces of test equipment you need. For JAMMA boards, perhaps a logic probe is better. For other boards and situations, a comparator is useful. For more complex boards, you might need a logic analyzer. And never forget about the Fluke 9010A + pods ... very useful.

Anyway, a scope is a necessity. Learn how to use it and then venture forth and find other equipment that will help you fix your boards.
 
Thanks for your input gentlemen. I'm in the process of upgrading my toolset as I'm tired of having so many kind of working PCB's on the shelf. Logic probe, oscilloscope, and a better programmer are on the short list.

I'm looking into the DS1054z at the moment, it's about the top of my price range for this one tool and being able to upgrade it for free is a plus, and it has lots of good reviews, and mentions on here etc. Plus buying new has its own benefits that I wouldn't get with an older scope, like warranty/manufacturer support.

I've got several boards that work fine, but controls don't work, or just one of the player's controls don't work, and two Combatribes boards that play fine but won't hold a sync on any cabinet I own. Think I'm approaching a dozen not-working-so-great PCB's, almost all of them came either as part of a lot with something I did want, or came with a cabinet I bought, etc. It's time to do something about it :).

Plus, learning on broken things is best because they're already broken!
 
A good desoldering station is a must to prevent accidental trace and pcb damage.

You could get away with shot gunning parts and a logic probe.

A scope will narrow down the problem and help in figuring out which part. 500 plus scope or a 25 dollar logic probe and 5 dollars in ic chips.
 
I have several o-scopes that I bought out of university or gov surplus over the years. I never paid more than $20 for one. Mine are 35-100MHz analogs and the one I find most valuable is the one with X-Y inputs for checking video output on vector games. I wish I could figure out how to use the Z input for the trigger, but my scope doesn't seem to work... probably operator error.

Besides this, I think you can get by with a logic probe for raster game boards.
 
So your telling me your ready for truth tables and learning the function of IC chips?

Here's my comparison: I don't randomly replace parts in my truck when something starts failing in hopes it will work when done. I learn about the new issue. I buy the service manual, I scour the internet for other people's experiences, if needed I buy the tools to properly diagnose it (chances are by now I already have them), and then buy the correct parts, and the necessary tools to do the job.

I have learned to do everything from change the oil to rebuilding an engine, out of enjoyment of working on vehicles and an interest in how they work. It has saved me thousands upon thousands of dollars in my lifetime so far, it's been enjoyable, and I'm more well-rounded of a person for having put the time and energy into learning how to do these things.

I don't see the point in not learning new things. I can go the shotgun route, hope and pray, and if that doesn't fix anything, have learned nothing AND still be unable to repair it, or I could learn an entire new skillset.

Why on Earth would I not want to become more knowledgeable? Especially about a hobby I enjoy? Simply doesn't make sense to me.
 
Some cars today need a very special computers with the updated software in order order to make adjustments. Some cars are were design not to be very user friendly.

Have I shot gun a car repair before? Yes. I spent 300 dollars in parts to rebuild the front end of a few car. Struts, bearings, ball joints and steering connecting rods, brakes and brake lines. I have found that over time when one part fail the other parts start to fail. I figure since I am working on the bearing, I might as well replace other parts since I am there. I have cars that have over 300K miles on them. Must be doing something right.

I am not trying to discourage you in learning electronics. It is a fun field to work and to play in.
I play with old electronics in arcade machines. I find it fun to figure out what has gone wrong. It is different from building something from scratch. I have built stuff that has been in the ocean for years and data recorders that have been sunk in concrete. No way of servicing it once it bury under tons.

Some people get into learning electronics in order to do cheap repair. If you talked to any tech and ask them how much does their arcade bench with all their tools and parts cost them. For a small bench the number that get tossed out is about 10k to 20k. For bigger bench and a bigger inventory 40K.

Have fun learning your new skill set.

Found this pdf.
Digital Design by Morris Mano
https://www.cse.iitb.ac.in/~srinath.naik/books/digital_design-__morris_mano-fifth_edition.pdf
 
I wasn't suggesting it can't be done, just that often it's unnecessary. I'm not quite in the 300k club just yet, but I've got 1 over 250k. There's definitely something rewarding about keeping a vehicle on the road way after others would have sent it to the junkyard.

I am certainly not expecting for this to be cheap, or even cheaper than paying someone to fix my boards, but maybe across the next few decades I'll find my way into the black. And even if I don't, there's value in experience.

Thank you for the link, I downloaded it and will toss it on the iPad tomorrow for easier reading.
 
I wasn't suggesting it can't be done, just that often it's unnecessary. I'm not quite in the 300k club just yet, but I've got 1 over 250k. There's definitely something rewarding about keeping a vehicle on the road way after others would have sent it to the junkyard.

I am certainly not expecting for this to be cheap, or even cheaper than paying someone to fix my boards, but maybe across the next few decades I'll find my way into the black. And even if I don't, there's value in experience.

Thank you for the link, I downloaded it and will toss it on the iPad tomorrow for easier reading.

i would like to see pictures of the 250k one!!
 
I am certainly not expecting for this to be cheap, or even cheaper than paying someone to fix my boards, but maybe across the next few decades I'll find my way into the black. And even if I don't, there's value in experience.

I hope you have as much fun as I or more.
I like working on cars and I like working on electronics.

You should volunteer your time at the arcade expo in banning. :)

You can talk to other techs and see how others work on arcade machines.

We should be able handle PCB repairs soon. Just need to order more parts.
 
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