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AuthorTopic: "broken capacitor"  (Read 942 times)

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Offline aseeley

"broken capacitor"
« on: May 14, 2006, 05:56:33 AM »
I have an amiga 4000 that i recently tried to replace a battery on. after repeatedly rosining and soldering in a new battery i find it still does not work. HOWEVER, and this is the point of the post, I found a capacitor rolling around in the case. It is the capacitor and the black "Board" that it is mounted on. THe spot it is missing from is just to the right and toward the rear of the 4000 from the power supply plug on the MB. the capacitor is C194, just to the left of it is c196. the maching still runs but i didnt run it long for fear of wrecking it. Does anyone know what this capacitor is for. and how can someone with very limited electronics experience fix it. I dont really see how it mounts to the MB. the place where it was mounted is got a kind of black substance on it i think, at least it is not the color of the rest of the MB.
thanks in advance, alan :-?

Offline Zac67

Re: "broken capacitor"
« Reply #1 on: May 14, 2006, 07:41:58 AM »

Offline Oliver

Re: "broken capacitor"
« Reply #2 on: May 14, 2006, 08:10:14 AM »
Hi aseeley,

Welcome to the forum.  I have posted an image of the schematic showing that capacitor.  I think there will be a delay before the image is available (it will be checked by mods).  You should be able to find the a link to the image by clicking on my name next to this post.

As mentioned above, that capacitor is used for filtering the power supply (-12V line).  It sits between the -12V supply and the power ground (0V).  AC noise which appears on the -12V line will have a low impedance path to ground through the capacitor(s).

If the capacitor has leaked, there could be damage to the functioning of other components as well.

Without that capacitor, components using a -12V supply will receive more noise (possibly too much), and may not function correctly.  This can cause intermittent failures.

The problem should be fixed.  If you're not confident about fixing it, then find someone to help you.  The capacitor should not be hard to find in a good electronics store.

Good good study, day day up!