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Ivan Vegvary <ivanvegvary@gmail.com>: Oct 26 12:55PM -0700 Would like to hook up my newish Rigol 4 channel scope to analyze ignition in my 1948 Pontiac. Need hookup and safety information. Entering "lab scope ignition testing" etc. leads to hundreds of links but they are ALL automotive scopes e.g. Sun, Snap-On etc. They all claim the words "lab scope". Could anybody suggest a better search term. All responses greatly appreciated. Ivan Vegvary |
"pfjw@aol.com" <pfjw@aol.com>: Oct 26 01:06PM -0700 On Wednesday, October 26, 2016 at 3:55:56 PM UTC-4, Ivan Vegvary wrote: |
"pfjw@aol.com" <pfjw@aol.com>: Oct 26 01:09PM -0700 On Wednesday, October 26, 2016 at 3:55:56 PM UTC-4, Ivan Vegvary wrote: > Could anybody suggest a better search term. > All responses greatly appreciated. > Ivan Vegvary file:///C:/Users/pweick/Downloads/ETI_Feb77_ScopeTheIgnition_1b.pdf http://int.rigol.com/Applications/Car/?lc=EN Would these help? Peter Wieck Melrose Park, PA I am not a member of any organized political party. I am a Democrat. Will Rogers |
Ivan Vegvary <ivanvegvary@gmail.com>: Oct 26 01:43PM -0700 Thank you PF. The link does tell me what is possible. I suppose by 'high pressure pdobe' they mean 'high voltage. Hookup diagrams would be nice to have. Of course the only electronics in a 1948 auto is the ignition system. Would love to look at 4 cylinders (8 total) at a time with the Rigol. I do have inductive pickups that I can salvage from timing lights. |
mike <ham789@netzero.net>: Oct 26 03:11PM -0700 On 10/26/2016 1:43 PM, Ivan Vegvary wrote: > Of course the only electronics in a 1948 auto is the ignition system. > Would love to look at 4 cylinders (8 total) at a time with the Rigol. > I do have inductive pickups that I can salvage from timing lights. Exactly what do you expect to see? What are you gonna do with the information when you get it? Is the benefit derived from that worth the risk of blasting the front-end out of your scope? What you see on the scope is likely to be more dependent on your probing technique than the signals present. When I experimented with monitoring fuel injection, I had trouble getting rid of the ignition noise so I could look at the injectors. I have a Snap-On automotive scope with an input voltage rating of 500V with 30KV surge rating, whatever that means. I wouldn't go poking around aimlessly with that either. I'm sure it's completely safe...except when it isn't. Keep your digital scope out of your car unless you really, really need to measure something that you can control to FIX something that's broke. Even the 12V...I guess it was 6V in 1948...electrical system is risky. http://www.littelfuse.com/data/en/Application_Notes/an9312.pdf |
Ivan Vegvary <ivanvegvary@gmail.com>: Oct 26 03:19PM -0700 On Wednesday, October 26, 2016 at 3:12:34 PM UTC-7, mike wrote: > broke. > Even the 12V...I guess it was 6V in 1948...electrical system is risky. > http://www.littelfuse.com/data/en/Application_Notes/an9312.pdf Thanks Mike, I thought if I could see all the ignition activity at the same time (or at least 4 at a time) I could look for anomalies and identify a poorly firing spark plug or semi-faulty wire. Thanks for the cautionary note. Will heed. Ivan Vegvary |
whit3rd <whit3rd@gmail.com>: Oct 26 05:41PM -0700 On Wednesday, October 26, 2016 at 3:19:48 PM UTC-7, Ivan Vegvary wrote: > I thought if I could see all the ignition activity at the same time (or at least 4 at a time) I could look for anomalies and identify a poorly firing spark plug or semi-faulty wire. Yep, the low-voltage terminal of a spark coil does give that kind of info. You can identify (or so I'm told) variations in fuel mixture from cylinder to cylinder that way (higher breakdown voltage for rich fuel mixture). It takes a 500V scale for the o'scope, though ('low voltage' means +12 to minus 300 or so...). A transformer clip-on probe can trigger your 'scope from cylinder 1, which simplifies the analysis if your auto has a single coil for all the cylinders. |
mike <ham789@netzero.net>: Oct 26 07:38PM -0700 On 10/26/2016 5:41 PM, whit3rd wrote: > On Wednesday, October 26, 2016 at 3:19:48 PM UTC-7, Ivan Vegvary wrote: >> I thought if I could see all the ignition activity at the same time (or at least 4 at a time) I could look for anomalies and identify a poorly firing spark plug or semi-faulty wire. > A transformer clip-on probe can trigger your 'scope from cylinder > 1, which simplifies the analysis if your auto has a single coil for all the > cylinders. You have to be careful NOT to assume normal conditions when detecting faults, which by definition, are NOT normal conditions. Stuff happens. It's best if that stuff doesn't happen when you're probing around with an expensive digital scope. 300V might be a fine number under normal circumstances, but, if a wire is bad and the plug fires at a much higher coil secondary voltage, the primary may also show a much bigger spike. And there's always the temptation to crank up the sensitivity to see some smaller wiggle on the trace. That may be a bad idea in this case. A plug either fires or it doesn't. If it fires, the thing you are interested in is the current. After it arcs, the voltage will be determined by the plug and wire/coil resistance/inductance. High current >> fat spark >> good. Of course, that assumes that the current is all going thru the plug and not arcing to ground thru a crack in wire insulation. If you have a clip-on current probe of known transient response, you can clip it on the coil output and look at the relative currents for all the cylinders. Properly insulated current probe designed for ignition service should be safe to use on your scope. If you try to move the probe to different plug wires, you'll probably see more variation in the coupling than in the actual signal. It's a vintage car. If it runs, drive it proudly. If it runs like it has ignition problems, change the plugs. If that doesn't fix it, work your way back toward the battery. Run it in the dark and poke around the wires with a grounded probe to look for insulation faults. You can learn some interesting things by pulsing the coil with the engine off and listening to the coil. But, you can smoke the coil if you're not careful. Rule number one... If it ain't broke, don't try to fix it using your expensive scope. Rule number two... If it IS broke, don't try to fix it using your expensive scope, except as a last resort. |
Bruce Esquibel <bje@ripco.com>: Oct 27 10:22AM > I thought if I could see all the ignition activity at the same time (or at > least 4 at a time) I could look for anomalies and identify a poorly firing > spark plug or semi-faulty wire. Ok but it still begs the question, why? I can't see a set of new plugs, wires, cap, rotor, points and condenser running more than $50 dollars or so. I'd just replace everything and if you think something is wrong, look elsewhere. You didn't say where and what condition this car is in, but time and money spent on a compression test and carb rebuild kit wouldn't be money ill spent. That and a timing light. It's a novel idea but the scope isn't going to give you any more ideas than a good set of ears and eyes will. -bruce bje@ripco.com |
Ivan Vegvary <ivanvegvary@gmail.com>: Oct 27 06:08AM -0700 Thank you all. Scope will not be used on ignition. Car runs fine. Lesson(s) learned. Great group! Ivan Vegvary |
Ralph Mowery <rmowery28146@earthlink.net>: Oct 27 10:58AM -0400 In article <nuskhl$4m5$1@remote5bge0.ripco.com>, bje@ripco.com says... > a good set of ears and eyes will. > -bruce > bje@ripco.com I agree that unless there is some odd problem, just replace everything for a few dollars insted of maybe messing up a scope that is a thousand or so dollars. If there is an odd problem, maybe you could find someone that has one of the old Sun scopes. For the old cars just see if you can find a timming light and dwell meter. |
Jeff Liebermann <jeffl@cruzio.com>: Oct 27 08:57AM -0700 On Wed, 26 Oct 2016 12:55:53 -0700 (PDT), Ivan Vegvary >Entering "lab scope ignition testing" etc. leads to hundreds of links but they are ALL automotive scopes e.g. Sun, Snap-On etc. They all claim the words "lab scope". >Could anybody suggest a better search term. >All responses greatly appreciated. One of my customers uses one of these: <http://www.ebay.com/itm/Hantek-Virtual-Oscilloscope-8CH-Programmable-Generator-CE-Auto-Ignition-Probe-/140921187522> <http://www.hantek.com/en/ProductDetail_136.html> <http://www.hantek.com/en/ProductDetail_56.html> The couplers are pricy: <http://www.ebay.com/itm/7pcs-HT-25-Auto-Ignition-Probe-For-Hantek-Automotive-Diagnostic-Oscilloscope-/140855478422> <http://www.ebay.com/sch/i.html?_nkw=8+ignition+probes> <http://www.hantek.com/en/ProductDetail_15_11165.html> Note that these are for "coil on plug" type engines, which are unlikely to be found on a 1948 Pontiac. Maybe a coupler or ignition probe like one of these: <https://www.pinterest.com/ADPTraining/scope-1-automotive-engine-analyzer-oscilloscope/> <https://s-media-cache-ak0.pinimg.com/originals/2a/ee/3b/2aee3b18361772ee3ebbc98973cbf2e3.jpg> -- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
N_Cook <diverse@tcp.co.uk>: Oct 27 03:18PM +0100 With the built in temp comp diodes, 1 silicon in the N type and 5 Schotky in the P and mirror-reversed pinning . Owner put a short across one speaker line, magic smoke but other channel is normal. Internal emitter resistor .22R of the p type is now not .22R. I intend removing both , of the failed channel , to check out of circuit, but anyone jumpered in an external .2R in these circumstances and no further problems from cracked die etc as this R is part of the die? The datasheet I think , in fractured English, says the thermal safe operating over-current zone, for the built in .22R is deliberately lower than the Darlington itself. Anyone ever disentangled the "English" referring to deliberately? destroying the internal R so as to use an external emitter R,or is it just referring to doubling-up ? datasheet http://pdf1.alldatasheet.com/datasheet-pdf/view/38213/SANKEN/SAP15/+2732WUOYLI.OcU.utw+/datasheet.pdf |
"pfjw@aol.com" <pfjw@aol.com>: Oct 26 01:00PM -0700 On Wednesday, October 26, 2016 at 11:50:33 AM UTC-4, MJC wrote: > I suppose all saboteurs could be called a footnote :-) At least they got a name. Peter Wieck Melrose Park, PA I am not a member of any organized political party. I am a Democrat. Will Rogers |
etpm@whidbey.com: Oct 26 01:52PM -0700 On Wed, 26 Oct 2016 13:00:30 -0700 (PDT), "pfjw@aol.com" >On Wednesday, October 26, 2016 at 11:50:33 AM UTC-4, MJC wrote: >> I suppose all saboteurs could be called a footnote :-) Hey MJC, I just got your joke. Good one. Eric |
MJC <gravity@mjcoon.plus.com>: Oct 26 11:44PM +0100 In article <rr521ch9g2p62kvdo1cqd7bsuojg05r9im@4ax.com>, etpm@whidbey.com says... > >> I suppose all saboteurs could be called a footnote :-) > Hey MJC, I just got your joke. Good one. > Eric Thank you kindly! Mike. |
Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net>: Oct 26 07:09PM -0400 On 10/26/2016 11:50 AM, MJC wrote: >> ... Nor were the Luddites much more than an historical footnote. > I suppose all saboteurs could be called a footnote :-) > Mike. ;) (*) Cheers Phil Hobbs (*) "Saboteur" having originally meant "one who throws a wooden shoe (sabot) into the works". -- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC Optics, Electro-optics, Photonics, Analog Electronics 160 North State Road #203 Briarcliff Manor NY 10510 hobbs at electrooptical dot net http://electrooptical.net |
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