Connect with us

Newbie scope question

Discussion in 'General Electronics Discussion' started by tuc2k, Nov 2, 2018.

Scroll to continue with content
  1. tuc2k

    tuc2k

    9
    0
    Nov 2, 2018
    I would like to view auto spark wave forms and would like to know if a Tektronix 475 Oscilloscope can do that. If so would I need anything special? I don't want to buy one and it isn't able to do that function.
    Hope someone can help. Thanks
     
  2. hevans1944

    hevans1944 Hop - AC8NS

    4,537
    2,113
    Jun 21, 2012
    Auto spark wave forms are high voltage damped oscillations. To view them successfully on the 475 oscilloscope you need a frequency-compensated, high-voltage, attenuation probe, typically insulated with a fluorocarbon liquid insulator. The Tektronix P6015A is the "go to" probe for this purpose with 70 MHz bandwidth, 1000X attenuation, and 40 kV maximum pulse amplitude. Be aware that it is a little pricey, but this is the probe you need to use.
     
  3. tuc2k

    tuc2k

    9
    0
    Nov 2, 2018
    Thank you very much for that, appreciate it.............
     
  4. tuc2k

    tuc2k

    9
    0
    Nov 2, 2018
    Looks like that solution is priced out of my budget, but all good to know..........
     
  5. 73's de Edd

    73's de Edd

    2,922
    1,235
    Aug 21, 2015

    Sir tuc2k . . . . .

    Where is being . . .most honnable . . .Yankee Ingenuity ?


    On the economy side then, take NOT, a crocodile nor an alligator clip but, the third small battery type of squeezable compression connector and make connection to its terminal thru a stock scope 1x or 10x probe with a carbon composition 1 megohm resistor being used as an additional load match across the scope probes tip and ground lead, with the ground lead clipping closely by, to the metal of the motor for common ground.

    upload_2018-11-3_2-36-20.png

    That isolated capacitive pick up along with that 475 scope and its triggering capabilities, should give you a better waveform resolution than any garages Sun Engine Analyzer was ever able to produce.

    Should you find that the voltage spikes resultant vertical amplitude is being beyond range compensation of the vert sweep sensitivity setting. Add required extra megohms of attenuative resistance between the battery clip and the probe tips load resistor, you initially inserted. (As per the second illustration above .)
    You could also further attenuate by inserting proper insulative spacing between the plug wire and clips two jaws, so that they are capacitively spaced further from the plug wire.

    You then set vert amplitude, triggering and horizontal time base rate to get the best sized and stable.
    waveform. . . . . . and you then say WOWEEEEEEEE !
    Then squeeze the clip free and move to another plug for evaluation.
    Or you also could slow down the hoz time base sweep rate and watch multiple consecutive firings of that plug before the trace has to reset on retriggering.

    Thasssssssssssit . . . . . .

    73's de Edd
    ...................

    FLASH ! . . . . .now for some fascinating medical news:
    Doctors are now starting to use maggots to heal wounds. Now, this just doesn't make any sense to me.
    Now I ask you .... WHEN is the last time you saw an animal on the side of the road, being all covered with maggots,
    that looked like it was getting ANY better ?
     
    Richard9025 and hevans1944 like this.
  6. tuc2k

    tuc2k

    9
    0
    Nov 2, 2018
    Wow, now that sounds like something I can do............thank you for taking time to figure it out and send to me.
    I see a scope in my future....................


     
  7. duke37

    duke37

    5,364
    769
    Jan 9, 2011
    Many measurements of high voltage ignition systems look at the voltage producing the spark but this voltage will only be present if there is no spark.
    A better mearurement would be the current which would be present during the spark. An isolating current transformer would protect the scope and measure the spark. Decaying resonating voltage with insufficient voltage to reignite the spark will give the wrong impression.
     
  8. tuc2k

    tuc2k

    9
    0
    Nov 2, 2018
    I purchased the scope and can't wait to try it out. You've given me three solutions for auto spark, I'll start with the 2nd and then the third and see what happens.
    Thank you all,
     
  9. hevans1944

    hevans1944 Hop - AC8NS

    4,537
    2,113
    Jun 21, 2012
    You mentioned the Tektronix 475 oscilloscope in your original post... these were fine instruments when new and are available on the used market for very reasonable prices in the $200 to $500 price range. I have purchased two of them (used) over the past thirty years or so and they have given me very good service. Unfortunately, they are virtually un-repairable if they fail because of scarcity of replacement parts. Fortunately, however, technology has evolved and newer, less expensive, digital storage oscilloscopes (DSOs) are available with specifications comparable to the 475. I recently purchased a Hantek DSO and instantly fell in love with it.

    My motivation for buying a DSO began a couple of years ago when a friend on this forum gifted me with a small JYE DSO kit. It is easy to get your feet wet with a digital storage oscilloscope kit when the cost has dropped to less than twenty bux. You can jury-rig a pulse attenuator as others have described here, build the DSO kit, and try it out on the automobile internal combustion engine of your choice... all in just a few hours. Well, you might want to spend a day or two getting familiar with how to use the DSO to measure lower-level signals before moving on to arcs and sparks. Point is, the starter kits are inexpensive so you won't feel too bad if you blow one or two of them up before "getting the hang of it."

    If you participate in this forum, one nice thing to have is the ability to upload oscilloscope screen shots. The Hantek DSO (as well as others of this class) has this capability built in. With the "old school" Tektronix 475 you have to snap a digital photo with either a cell phone or other digital camera. Or maybe use a Polaroid instant camera and scan the resulting picture with a flat-bed scanner...
     
    Last edited: Nov 5, 2018
  10. tuc2k

    tuc2k

    9
    0
    Nov 2, 2018
    If 475 is dead or I end up with it in smoke then you have given me a whole new and economical way to go. Should be interesting to see how this turns out. Yes I could just change all the plugs, plug wires, rotor, dist cap but that would just be to easy.

    Thanks again........
     
  11. Bluejets

    Bluejets

    4,227
    897
    Oct 5, 2014
    I'd be inclined to add some extra insulation on the jaws of the pickup.
    Older leads especially can fire straight through the ht lead given even a hint of an earth return and the first you'll know about it is when the scope goes blank.(forever)
     
    hevans1944 likes this.
  12. tuc2k

    tuc2k

    9
    0
    Nov 2, 2018
    Thanks for heads up......................
     
  13. hevans1944

    hevans1944 Hop - AC8NS

    4,537
    2,113
    Jun 21, 2012
    Been there, done that, all without ever using (or wanting to use) an oscilloscope. Too easy? Maybe for an auto built in the 1960s or earlier, but lately changing spark plugs and plug wires has become a real PITA, what with engines mounted sideways for front-wheel drive, and half the spark plugs and plug wires virtually inaccessible without removing the engine.

    I'm about ready to go back to "a little deuce coupe with a flat-head mill that will walk a Thunderbird like it's standing still... ported 'n relieved and stroked and bored she'll do 140 in the top end floored." With sincere apologies to the Beach Boys band.
     
    bushtech likes this.
  14. Bluejets

    Bluejets

    4,227
    897
    Oct 5, 2014
    hehehe...love it .....:cool:
     
  15. tuc2k

    tuc2k

    9
    0
    Nov 2, 2018
    Seems that the Tek 475 was DOA, was given Tek 5110 as sub., not sure if this was a ok deal or not? Comments please
     
  16. 73's de Edd

    73's de Edd

    2,922
    1,235
    Aug 21, 2015
    Thir tuc2K . . . . . . . . ooooooooops . . . that pesky 'lil lisp-th. . .again . . . .


    The 5110 (51XX) series of Teks are not even in the ballpark in their specs, as to be equated to the 475 or its baby brother 465.
    You would be wanting the 73XX and 76XX mainframe series, with their appropriate vertical and hoz timebase plug ins, with the whole cluster then being a like sub. (Those also have neanderthalic first generation on screen display graphics of settings.)

    Any additional different, ( or replacement plug ins for a bad one) on the (51XX ) series are very hard to be found.

    Of course . . . . if you are allured, stupefied, phantasmasized and spellbound . . . . by your just being able to capture and display a little green / blue trace line on the screen . . . . . . . .well . . . .

    PLUS . ..
    I don't think that you ever told the extent of monetary expenditure for the unit . . . . and its shipping !

    You say . . . .


    " Comments please"

    . . . . . .of course, if you merely want to display sparkley plug, firing bursts waveshapes on screen . . . you are O.K.


    73's de Edd
    . . . . . . . . . . . .


    I finally got 8 hours of sleep. Took me 4 days, but . . . . whatever. . . . . .

     
    Last edited: Dec 5, 2018
    Richard9025 likes this.
  17. tuc2k

    tuc2k

    9
    0
    Nov 2, 2018
    Thanks for your reply, I didn't think it looked anything like what I was expecting. Just a bad deal I guess, win some lose some.
     
Ask a Question
Want to reply to this thread or ask your own question?
You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.
Electronics Point Logo
Continue to site
Quote of the day

-