Bosch CDI box - incredible find

[ischmitz]

I just wanted share some pictures from a Bosch 3-pin CDI box I was working on this weekend. Often when issues with the CDI come up some seek alternatives while the Bosch boxes are really incredibly rugged and reliable. Especially given their average age of 40 years.

So just when you think you have seen it all I got this 3-pin box in. A quick functional test showed it whistled but there was no spark. So let's open it up to check what the issue might be. Here is the inside....



I don't know its history but it looks like it was either used on a submarine or must have been at the bottom of a lake or something for some time. Removing the circuit board revealed more mayhem:



What is incredible is that the box was still alive and making a whistling sound. So the DC/DC converter was working just fine. The one part that made it fail was a fractured wire to the internal main capacitor. Of course there was quite a bit more work that had to be done to prepare it for its next decade or more of service. Most of the wire insulation was merely dust and disintegrated on touch. But in the end it was all addressed.

This really speaks to the rugged reliability of this design. After a full rebuilt the box is returned to service.

[speedster911]

Did the car live on the east coast for a while? That's amazing

[Funracer]

Flood damage car maybe? It would be interesting to find out the history.

[Hx911]

thanks for sharing these picture - amazing how rugged that old stuff turns out.

[smadsen]

Is that dry chem from a fire extinguisher? Certainly is a rugged little unit.

[yelcab1]

And my iphone will die if I drop it in the toilet. It must be the urine acid.

[jjeffries]

To me the Bosch CDI is like the Bosch K-Jet ... given a modicum of care, it does its job really well, yet folks always seem to second-guess the engineering and go for aftermarket replacements. I'd prefer my Bosch box to a 6AL any day of the week.

John