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CDI repair

ex0r

Mar 16, 2014
15
Joined
Mar 16, 2014
Messages
15
Hello guys,

I recently acquired a jetski for free that I have been working on. I got to the point where I am ready to take it on the water, and found out that the CDI was bad, and is now no longer working. Being as a replacement is upwards of $350, I am wanting to attempt repair of the current one.

I have prior knowledge of electronics and soldering, and have done repairs of other electronic components before, but never worked on a CDI. In looking how they operate, it looks like it's mainly a capacitor, a transformer, and a small charging circuit. There also appears to be a power supply inside of it too that increases the output voltage. I have not tore into this particular CDI yet to see how it is setup, but I was wondering if it is in fact possible to service these, in the case, say, the capacitor goes bad?

It's a very old jetski, and it was working when I first got it, but after testing numerous times with a bad starter, I think we finally burned something up in the CDI. My plan was to remove the rubber covering the back of the unit, and using a multimeter test the resistance between the leads on the various components, as well as visually inspect components and traces on the board for damage, and, if it's possible, replace any components that are not working.

The real question I have, is if it's possible to service individual components (The likelihood of all components going bad at once is slim), and if it's safe to do so (There's a capacitor in there at least, that holds upwards of 500-600 volts), and if it's possible to safely discharge the capacitor.

Any insight would be most helpful.
 

skenn_ie

Sep 7, 2009
33
Joined
Sep 7, 2009
Messages
33
The first thing to look for is electrolytic capacitors that have a domed top. A sure sign of being faulty. Capacitors, and especially electrolytics have a limited life, and that life is fairly predictable depending on load factor, AC current, and time in use.
 
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ex0r

Mar 16, 2014
15
Joined
Mar 16, 2014
Messages
15
Yeah, in doing repair before (I used to fix xbox 360's), I am familiar with those types of caps. There were times too when the liquid inside would actually seep out of the top (the + on the top would actually rip open), and had to be replaced.

One problem I am going to run into, is removing the board from the box. It's in a small 3 sided box, with black epoxy/rubber sealant on the other end holding it in. I haven't taken it out of the box yet, but I am hoping that sealant isn't entirely encasing the board. If it is, I am going to have a fun time getting it off. (Although I have a heatgun, so I may just heat it up enough to melt it off, or to soften it up so I can easily remove it).
 

debe

Oct 15, 2011
278
Joined
Oct 15, 2011
Messages
278
What brand & model jetski is it? Pictures of the CDI unit would be helpful. If it has a HV inverter built in , then power it up & see if theres voltage across the capacitor. If theres no voltage the inverter is faulty. The capacitor doesn't normaly fail. Its usualy the inverter or the SCR which dumps the HV across the ign coil.
 
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