Bench testing the Bosch 3 pin CDI unit??

[Jens]

I found 3 of these in a box o' stuff under my workbench. I don't need all 3, but I would like to know if they are in working order if I decide to sell.

Thanks in advance for any guidance.

[Jens]

Damascus and ignition_________________________________

[304065]

Jens

CDI Units are dangerous and the 460V shock can kill you same as a damascus steel barrel bursting so be CAREFUl

A= achtung= 460V pulse (do not touch under any circumstances)
B= battery = connect +12v to test
C= contact = points terminal (contact between this and ground will fire the cap and probably destroy the unit if it's not connected to a load)
D= ground (don't know why "D" as the German word for Ground is "erde" but that is just a mystery of life)

So, put +12v on the B and ground the D and you should hear a high-frequency whistle if the unit is good. This whistle is actually caused by the transformer windings vibrating at like 3Khz-- there is a DC/AC inverter circuit that creates an alternating current which gets fed into the transformer, which steps it up to 460V to charge up the capacitor. Pow!

Of course something else could be messed up and the unit non functional, but this is a decent test to make sure somebody didn't leave the thing in their aquarium for the better part of a decade or something.

[Jens]

Lemme see if I have this right- 12v+ to B, D grounded to my wet left hand, tongue to A, no that can't be right. 4 ounces of black powder, handful of naught buck to proof test the old double, now I am confused.

Seriously, I very much appreciate your help and advice. This will at least get me started.

[mike curnow]

304065

If you do the test it charges the units capacitor, if all is well? Will it stay charged and fire off when you try and move it? Not from the move but because you touched it and grounded it?

Jens

CDI Units are dangerous and the 460V shock can kill you same as a damascus steel barrel bursting so be CAREFUl

A= achtung= 460V pulse (do not touch under any circumstances)
B= battery = connect +12v to test
C= contact = points terminal (contact between this and ground will fire the cap and probably destroy the unit if it's not connected to a load)
D= ground (don't know why "D" as the German word for Ground is "erde" but that is just a mystery of life)

So, put +12v on the B and ground the D and you should hear a high-frequency whistle if the unit is good. This whistle is actually caused by the transformer windings vibrating at like 3Khz-- there is a DC/AC inverter circuit that creates an alternating current which gets fed into the transformer, which steps it up to 460V to charge up the capacitor. Pow!

Of course something else could be messed up and the unit non functional, but this is a decent test to make sure somebody didn't leave the thing in their aquarium for the better part of a decade or something.

[beh911]

Guys,
I can't stress enough how important it is to truly understand these CD boxes before you mess with them. While my electrical knowledge is somewhere between key on a kite in a thunderstorm and EE major, I wouldn't embark on troubleshooting one as they are not for the casual weekend warrior with a multimeter.

The fact is they can hold a charge (a huge one), even after testing and removal from the car.

Be very careful

[Jens]

Throw a dart.

[ThomasTe]

Why not just test them in your car?

[Jens]

Thomas, that would be the easy way (and obvious), but I don't run the same unit. I also want to get a better understanding of the magic of these boxes.

[ThomasTe]

I fully understand. You might find this thread useful, if you have not already studied it:

http://forums.pelicanparts.com/porsc...chematics.html