Oscilloscope for dummies
  • Help
Results 1 to 19 of 19
  1. #1
    1000+ Posts jo proffi's Avatar
    Join Date
    May 2003
    Location
    sydney
    Posts
    8,496

    Default Oscilloscope for dummies

    Ever since I was a little kid oscilloscopes have fascinated me.
    B grade sci-fi, Dr Who and all that sci-fi series stuff I grew up on always had a scope display of one type or another slip into each episode.

    I probably should have bought one years ago when i worked in audio, but it was just one of those tools i put on the back burner, plus moving into digital, my gear either worked or it didn't and nearly all the time it did, so I never really found the pressing need for one.

    I'm now at the point where I want to learn up on ignition systems and make some changes to my car, and the time seems right to get a 'scope.
    The problem is I dont really understand the differences between all the products on the market, nor understand the basic kit required to diagnose things around the engine bay.

    Advertisement


    My primary aim at this stage is to monitor the ignition as I suspect there are some miss fires at idle but can not be sure.

    Would anyone have any tips on what would be a good basic kit and what leads/probes would be required.
    Whilst I have no idea what type of budget should be set, was hoping to spend up to about $300.
    Am I dreaming on that budget or can a useful tool be bought for that type of cash??

    Cheers, Jo

  2. #2
    1000+ Posts schlitzaugen's Avatar
    Join Date
    Nov 2010
    Location
    loneliness capital of the world
    Posts
    9,414

    Default

    I think you are kinda dreaming. Jaycar and others like that had until recently some tube scopes (made in China, of course) up to about 20MHz for about that kind of money. When I went to buy one, they said it was discontinued (some months ago). That would have been more than overkill for ignition. Dual trace (I think). Not that you need it. If you can find one lying about in some god forsaken store, grab it.

    These days it's all handheld and it starts above that (I think the cheapest I have seen is about 600$), and I am not sure how good they are in terms of responsiveness of the screen being LCD or some such.

    http://www.jaycar.com.au/productResu...2&keyform=CAT2

    There you, wrong again.

    PS. You're not thinking of hooking it up to the spark plug wires, are you?
    ACHTUNG ALLES LOOKENPEEPERS

    Das computermachine is nicht fur gefingerpoken und mittengrabben. Ist easy schnappen der springenwerk, blowenfusen und poppencorken mit spitssparken. Ist nicht fur gewerken bei das dummkopfen. Das rubbernecken sightseeren keepen hands in das pockets-relaxen und watch das blinkenlights.

  3. #3
    bob
    bob is offline
    1000+ Posts
    Join Date
    May 2001
    Location
    Skipton
    Posts
    2,579

    Default

    G'day Jo,

    there are a few old references here that I could scan a few pages for you. Your HT pickup is just a clip on detector, like you get with a timing light. Or, I seem to recall from eons ago when I had an old war surplus unit that did that job, a small bulldog clip

    Never even thought about the waveform for modern vehicles, you'll be able to write the new texts

    References here that might be around in http://used.addall.com/Used/ -
    Wanniger - Using electronic testers for car tune-up
    Evenson - Automotive test equipment you can build
    Lytel - Automotive electronics test equipment
    amongst others probably !
    these days a poke around at http://www.archive.org/index.php might even turn up PDFs !

    cheers,
    Bob

  4. #4
    1000+ Posts robmac's Avatar
    Join Date
    Nov 2004
    Location
    Melbourne / Caulfield
    Posts
    19,465

    Default

    Virtually any oscilloscope will do the job of the display. The frequency, nature of the signal and voltage levels involved are modest.
    Engine pick ups are likely to be the hardest parts, but if you are handy electronically they can be built. Being mainly resistive divider and inductive pick ups.

    FWIW I would not consider a CRO (cathode ray oscilloscope) unless it was very very cheap.

    Modern units like this (note the small size) give good bang for buck. Being ground isolated is an advantage.

    http://www.ebay.com.au/itm/AU-STOCK-...ht_3883wt_1193

    You need to check if probes are included, because they can cost quite a few dollars.

    What you are really looking for is an old vane engine analyser. This is custom designed for the purpose, with all the probes, vacuum measuring gear etc. But I guess they are worth a bomb and like hen's teeth.

    The advantage of the Vane gear is the how to use book that shows expected wave forms.

    EDIT: I have two scopes. The old Telequipment CRO and later Tektronic DSO.
    I haven't used the former for 15 years or more. It developed a "off horizontal" trace issue but works fine in both channels other that that (as I remenber)

    The telequipment scope is yours for the asking. I'm never likely to use it again since I have the Tek DSO now. The Telequipment has no probes, but you will be making something I would assume.

    PS
    It's a museum piece now! I purchased it in the 1970s to further my Electronics Hobby. So you will be taking a piece of test equipment history if you want it.
    Attached Thumbnails Attached Thumbnails Oscilloscope for dummies-cro.jpg   Oscilloscope for dummies-tek.jpg  
    Last edited by robmac; 15th April 2013 at 10:05 AM.

  5. #5
    con
    con is offline
    Fellow Frogger!
    Join Date
    Jul 2001
    Location
    sydney, nsw, australia
    Posts
    526

    Default

    Quote Originally Posted by jo proffi View Post
    Ever since I was a little kid oscilloscopes have fascinated me.
    B grade sci-fi, Dr Who and all that sci-fi series stuff I grew up on always had a scope display of one type or another slip into each episode.

    I probably should have bought one years ago when i worked in audio, but it was just one of those tools i put on the back burner, plus moving into digital, my gear either worked or it didn't and nearly all the time it did, so I never really found the pressing need for one.

    I'm now at the point where I want to learn up on ignition systems and make some changes to my car, and the time seems right to get a 'scope.
    The problem is I dont really understand the differences between all the products on the market, nor understand the basic kit required to diagnose things around the engine bay.

    My primary aim at this stage is to monitor the ignition as I suspect there are some miss fires at idle but can not be sure.

    Would anyone have any tips on what would be a good basic kit and what leads/probes would be required.
    Whilst I have no idea what type of budget should be set, was hoping to spend up to about $300.
    Am I dreaming on that budget or can a useful tool be bought for that type of cash??

    Cheers, Jo

    I have one of these. Works well.

    https://www.sparkfun.com/products/10244


    con...

  6. #6
    1000+ Posts jo proffi's Avatar
    Join Date
    May 2003
    Location
    sydney
    Posts
    8,496

    Default

    Quote Originally Posted by robmac View Post
    Virtually any oscilloscope will do the job of the display. The frequency, nature of the signal and voltage levels involved are modest.
    Engine pick ups are likely to be the hardest parts, but if you are handy electronically they can be built. Being mainly resistive divider and inductive pick ups.

    FWIW I would not consider a CRO (cathode ray oscilloscope) unless it was very very cheap.

    Modern units like this (note the small size) give good bang for buck. Being ground isolated is an advantage.

    http://www.ebay.com.au/itm/AU-STOCK-...ht_3883wt_1193

    You need to check if probes are included, because they can cost quite a few dollars.

    What you are really looking for is an old vane engine analyser. This is custom designed for the purpose, with all the probes, vacuum measuring gear etc. But I guess they are worth a bomb and like hen's teeth.

    The advantage of the Vane gear is the how to use book that shows expected wave forms.

    EDIT: I have two scopes. The old Telequipment CRO and later Tektronic DSO.
    I haven't used the former for 15 years or more. It developed a "off horizontal" trace issue but works fine in both channels other that that (as I remenber)

    The telequipment scope is yours for the asking. I'm never likely to use it again since I have the Tek DSO now. The Telequipment has no probes, but you will be making something I would assume.

    PS
    It's a museum piece now! I purchased it in the 1970s to further my Electronics Hobby. So you will be taking a piece of test equipment history if you want it.
    Wow, Rob thats a very generous offer on top of you usual good advice.
    I had a chuckle at the vane suggestion though, my engine management and other bits and pieces are 20 years ahead of that technology.

    Digging holes in the ground today gave me plenty of time to give this proposed acquisition some more thought, and it occured to me that a bench unit is no good when your garage is so full of shit that the car wont be able to get within 20 foot of it.
    For that reason, and the fact that I live 1000km from you, I will pass on your offer for now. Thank you all the same.

    That leaves the little mobile phone sized ones or a PC units as being more suitable for my needs

    Yesterday I pulled a figure out of the air...$300, and found this little unit today on the net which fits just into that budget (less leads).
    http://www.bitscope.com/product/BS10/

    Hardware/software does not phase me either way, but the portability seems like a bonus and the fact that it can be used on a mac or a PC also suits my needs.
    It is not only made in australia, but locally to me in st leanards, which gives me a warm fuzzy feeling that if I spend the dollars, they are staying in my local community.
    Also handy when I fry it and need it serviced.

    Any thought on that unit??

    Jo

  7. #7
    1000+ Posts robmac's Avatar
    Join Date
    Nov 2004
    Location
    Melbourne / Caulfield
    Posts
    19,465

    Default

    Quote Originally Posted by jo proffi View Post
    Wow, Rob thats a very generous offer on top of you usual good advice.
    I had a chuckle at the vane suggestion though, my engine management and other bits and pieces are 20 years ahead of that technology.

    Digging holes in the ground today gave me plenty of time to give this proposed acquisition some more thought, and it occured to me that a bench unit is no good when your garage is so full of shit that the car wont be able to get within 20 foot of it.
    For that reason, and the fact that I live 1000km from you, I will pass on your offer for now. Thank you all the same.

    That leaves the little mobile phone sized ones or a PC units as being more suitable for my needs

    Yesterday I pulled a figure out of the air...$300, and found this little unit today on the net which fits just into that budget (less leads).
    http://www.bitscope.com/product/BS10/

    Hardware/software does not phase me either way, but the portability seems like a bonus and the fact that it can be used on a mac or a PC also suits my needs.
    It is not only made in australia, but locally to me in st leanards, which gives me a warm fuzzy feeling that if I spend the dollars, they are staying in my local community.
    Also handy when I fry it and need it serviced.

    Any thought on that unit??

    Jo
    Have a chuckle with me too, I had in my minds Bob created the post, when i offered the old scope as a giveaway.

    Later on it dawned on me that shipping four "house bricks" to NSW would be impractical.

    The unit you have is chosen is real overkill for you needs. The $100 suggested by Con or the $68 cheapie from (if it works and arrives) would be fine.

    But.. you always "grow" into test gear. Immediately you "get a picture" of what is happening diagnoses of problems are easier.
    When you get it, make a habit of connecting to everything, audio stuff, digital stuff, the door bell etc etc to get a feeling for what is normal and to become proficient at the controls, Knowing the instrument is essential to use it as tool. This is more so for yourself because are a learner from school of hard knocks and not from book learning.

    This is not meant as a negative. Some of most qualified engineers are morons practically and couldn't make a globe light off the battery.

    However some amateur radio operators would leave most engineers for dead because they have learnt from hands on and picked up the theory afterwards.

    Learning to use and interpret a DSO will be steep learning curve, but you will be up to it.

    If the $300 is no problems by all means buy local. You will have somewhere to take if it doesn't work or you have questions. It is probably miles better than a cheapie anyway.

    One word of warning. Many of these "pico scopes" will not tolerate mains voltages due insulation ratings of the pcb and the component ratings. You should check this manufacturer. For my money I would not go near 240vac mains or switch mode power supplies.

  8. #8
    bob
    bob is offline
    1000+ Posts
    Join Date
    May 2001
    Location
    Skipton
    Posts
    2,579

    Default

    G'day Jo,

    I see that those references I gave above are available on line for very little - I can scan the relevant pages though if you like ?

    Bit of googling provides....
    http://bmw.workshop-manuals.com/3_Se...dex.php?id=508
    through to....
    http://bmw.workshop-manuals.com/3_Se...dex.php?id=510
    for modern systems. Look pretty much like the olden-time pix I think, but the oldies are going to show point/condenser problems etc, are these display symptoms appropriate for modern systems ? could be a whole new ball game ?

    cheers,
    Bob

  9. #9
    1000+ Posts jo proffi's Avatar
    Join Date
    May 2003
    Location
    sydney
    Posts
    8,496

    Default

    Quote Originally Posted by bob View Post
    G'day Jo,
    I think, but the oldies are going to show point/condenser problems etc, are these display symptoms appropriate for modern systems ? could be a whole new ball game ?

    cheers,
    Bob
    Dwell is still dwell, (and misfire is still misfire) but my engine uses electronic control of it by the bosch 008 (smart) modules, and is not adjustable.
    At best i can simply observe the result. I still want to do that though because whoever designed my ignition system took the unconventional route of ganging two coils of the one ignition module to get the wasted spark, as opposed to using a single coil with dual post output.
    I will be adding knock controll soon and would like to observe aspects of the knock sensor signal, the controller's modifications and the end result to the engine.



    Jo

  10. #10
    1000+ Posts jo proffi's Avatar
    Join Date
    May 2003
    Location
    sydney
    Posts
    8,496

    Default

    Looking stuff up on the net and have come across some good info.
    I'll post some here.

    An oldie but a goodie....
    http://books.google.com.au/books?id=...20test&f=false

  11. #11
    1000+ Posts
    Join Date
    Mar 2004
    Location
    Melbourne
    Posts
    5,685

    Default

    A simple strob timing light will show misfire (not as well as a scope, especially one that stores info)
    "The enemy of knowledge is not ignorance, it's the illusion of knowledge"
    Stephen Hawking

  12. #12
    Member
    Join Date
    Feb 2011
    Location
    Brunswick Heads NSW
    Posts
    95

    Default

    I recognise that PM cover as one that's been hanging around at our house for the last umpteen years....

  13. #13
    1000+ Posts jo proffi's Avatar
    Join Date
    May 2003
    Location
    sydney
    Posts
    8,496

    Default

    Quote Originally Posted by frankthezapper View Post
    I recognise that PM cover as one that's been hanging around at our house for the last umpteen years....
    Its pretty cool retro. Love the skivvies and beige.

    Jo

  14. #14
    1000+ Posts PugMonkey's Avatar
    Join Date
    Nov 2010
    Location
    Brisbane
    Posts
    1,389

    Default

    BitScope is good - I have seem it in action, albeit in use with a spectrum analyzer. Plugged into a good lap top you will have a good portable tool.

    I have a Goldstar 20mhz dual trace scope 'cause it's the devil I know! If i'm trying to read anything that this scope won't do, them I find myself way out of the electronics ball park.

    Moo
    ....now watch a Peugeot turn into a corner!

  15. #15
    1000+ Posts jo proffi's Avatar
    Join Date
    May 2003
    Location
    sydney
    Posts
    8,496

    Default

    Being unable to edit my posts makes the concept of linking good resource sites tedious, but until something is sorted (or unless a moderator wants to wipe my bum for me and move this link to post #10 and delete my whinge) here is another great link explaining probes.

    http://www.ece.vt.edu/cel/docs/Probe..._Tektronix.pdf

    Jo

  16. #16

  17. #17
    1000+ Posts jo proffi's Avatar
    Join Date
    May 2003
    Location
    sydney
    Posts
    8,496

    Default

    I found these being thrown out.
    The dude reckoned they worked.
    No leads or anything, but in very clean condition and tagged (ohs) up until 2005.
    Attached Thumbnails Attached Thumbnails Oscilloscope for dummies-scopes.jpg  
    Last edited by jo proffi; 3rd May 2013 at 12:59 AM.

  18. #18
    COL
    COL is offline
    A110 COL's Avatar
    Join Date
    Mar 2002
    Location
    Van Diemen's Land
    Posts
    4,465

    Default

    Quote Originally Posted by jo proffi View Post
    I found these being thrown out.
    The dude reckoned they worked.
    No leads or anything, but in very clean condition and tagged (ohs) up until 2005.
    I have a similar one to the one on the left, its a Trio 20MHz osilloscope. Was around $800 new when I purchased it 30 years ago.

    Jo leads should be easy to obtain from Ebay, Element 14 or local electronic stores.
    Regards Col

    1973 Renault R12 Station Wagon
    1976 Renault R12 Station Wagon
    2002 Renault Laguna V6
    1973 Alpine A110

    http://alpine-a110.weebly.com/

  19. #19
    Fellow Frogger!
    Join Date
    Oct 2012
    Location
    Sydney
    Posts
    601

    Default

    I've got two, only need one. The one I am willing to part with is a Phillips 2 channel CRT analogue scope, no storage or anything fancy. I think it's a 100MHz bandwidth scope. I can supply it with the service manual but no probes. If you want it let me know, you can have it for a 6 pack of something decent.

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •