SVDA Dizzie Failure sorted out

Apr 08, 2004 27 Replies

let me tell you folks why....

Universal Corp (who made/sold the Tiger CDI) and ACN had a good working relationship. They sold the CDI with a lifetime warranty too! As is becoming more common, the company was bought out, and the bean counters there changed

2 things that affected the CDI.

1) no more lifetime warranty. They also declared that they would not honor the warranty that existed on their units previously sold with the "lifetime warranty" attached to them. This also affected their "relationship" with a certain employee they had there, that always bent over backwards (WAY backwards) to fix problems, or come up with new products (the 6V CDI was done by him on our request). Seems this fellow no longer works there; it's a shame too, he seemed the model employee AFAIAC. But either they fired him, or he left, but no matter he is no longer there, and besides they still don't offer the lifetime warranty anyways.

and

2) they figured they could make more $ if they raised the price about 50%. Their bean counters had obviously never taken economics 101, where even the C student figures out that if you raise the price too much, sales plummet and you make less (someday perhaps the Govt and IRS would figure this out too, but don't count on it). I can only conclude that this is exactly what happened, because when they first tried this tactic on us 2 years ago, we just told them "they were crazy and best of luck in your business". I also found it humorous that they called us up not 3 weeks ago stating they had dropped their prices back down again (too little, too late folks), but we'd already found a superior product, nicer housing, etc etc. They slit their own throats.

This is evolution in capitalism I suppose, seems that Darwin works here too.

John Aircooled.Net Inc.

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The 'fallback/bypass' mode you are so concerned about is a SWITCH for crysakes!

CDI module is a DC-to-DC inverter that pumps about 300 volts into a 1uF cap that gets discharged through the ignition coil when the points open. A number of handy circuits to accomplish this have been published since the mid-1960's and have appeared in virtually every electronic rag on the street. The circuit used by Delta, Archer, Universal and others was published in Nuts & Volts a few years ago and enhancements to it have appeared in QST, 73 and Ham Radio.

Or you can go hi-tek and opt for a multiple discharge circuit (although it won't do you any good in a low compression, low rpm VW). John Clarke published a bulletproof mil-spec version in Silicon Chip in 1997 and I know it's here on the internet somewhere because a fellow was flogging the circuit boards for it, citing John's article as the source for the parts list & assembly instructions.

And if none of that blows your skirts up, get one of the 6v units from John and rewire the input (the guts are the same).

I mention all this because you went through the trouble of telling us your Call Sign, letting the world know you're a smart fellow and an electronics guru.

-Bob Hoover

-KA6HZF (that's a General ticket, by the way)

-PS Modern vehicles don't use CDI because electronically-switched Kettering systems are less expensive. To achieve efficient ignition above 2500 rpm they simply got rid of the distributor, going to a waste-spark arrangement similar to that used on some motorcycles since the 1920's. To get more spark energy they simply wound coils having higher turns ratios. This gives you a higher secondary voltage that offsets the normal voltage 'droop' as the rpm increases. The system is able to live with the higer voltages at low rpms because of better insulation on the plug leads and the elimination of the distributor function. Want one? The Compu-fire DIS-IX is an electronically switched waste-spark system that clips on to a -009... and can be fitted to a vacuum-advance unit if you know how to twirl your wrenches right.

But even waste-spark will soon be history. The current hot set-up is to have the ignition coil wound into the lead AT the spark plug, giving you one coil per plug. COP (coil-on-plug) systems need a computer to keep things running but nowadays the typical car has half a dozen microprocessors on-board.

And COP systems are just a step along the way. R&D vehicles are already running in which the fuel injector, spark plug and ignition coil are a single unit.

Ignition-wise the Real World is COP, waste-spark and OBD-III. Air cooled veedubs are Basic Ketting, circa 1919, about as complicated as a flashlight.

Shoot, Bob -- I'm not posting my call sign to look like some kinda genius. I just have a lowly no-code tech license. Got it after being trapped with my (then) 12 year-old son in a tent in the backcountry when a surprise blizzard hit. Seemed a good idea to be legal considering how many repeaters are in the mountains around here. A well-motivated child could pass the no-code tech test. I'm surprised I did.

Your comment that CDI systems should be easy for an electronics guru are most likely right-on. Not being familiar with their internal workings (stopped reading Popular Electronics et al in the late 60's, my interest leading me to music and audio electronics) I'd want to find some representative schematics before jumping in and modifying a 6-v one to handle 12-v. My understanding is that a car is a pretty hostile environment to electronics so, being a cautious daily driver, I would prefer to stick in a Known Brand with a Good Reputation rather than building my own.

Knowing that the bypass mode is little more than a switch (who would know these things without asking questions?) is useful. Thanks for taking the time to point that out.

Seen many a good little brand vanish that way. Thanks for the background.

I LOVE the CDI systems. I bought and built my first one in 1966. It blew an inverter transistor in about '70, but I replaced it and it ran for about another 6 years when I sold that car and the next owner proceeded to destroy it, and the car.

I have several of the Original Delta Mark 10s and Mark 10-As, as well as a Heathkit. Several of the Deltas have problems now, or are completely shot (bad transformers, potted so I don't think I'll be able to repair them.) I need to find replacement SCRs for some of the others. I bought a basket full of them at a swap meet last fall and I suspect that most of them have some kind of problem. I hope to go thru them all this spring and pick out the good ones to sell to discerning VW owners who appreciate a good thing.

So, no, they are not completely bullet proof, but then again nothing else is either. I still think they are the best deal around.

-

----------------------------------------------- Jim Adney snipped-for-privacy@vwtype3.org Madison, WI 53711 USA

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Keep us posted.

In the meantime (and this might be a post for sci.electronics.misc) does anyone have pointers to schematics and other dummies guides to CDI systems?

Bob Hoover has shamed me into wanting to learn how they work and looking at implementations.

Back when I was in school, I often thought Keynsian econ theory and Darwinism were very similar. The weak should be allowed to die. ;-)

Max

sci.electronics.misc) does

guides to CDI systems?

work and looking

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