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Hi

 

I just need a second opinion and potentially a little help locating a part.

 

I am taking apart an iMac G3, cleaning and inspecting after I found a compromised battery. While going through the process I discovered that the largest capacitor on the Power Supply Board, Ver. 2 appears bulged to the touch and visually. Now, I did try to locate this part and it appears available in bulk which I don't want, I only need one but I was thrown off by the 400wv designation. What does wv mean?

 

Could someone confirm if this is indeed a bulged cap and if you think it is, where can I find one?

 

It reads SMH 470uF 400wv (M) 85°C (location is C905 on the Power Supply Board v.2)

 

Pics of the cap.

post-2686-0-01300700-1506850953_thumb.jpg

post-2686-0-13323600-1506850971_thumb.jpg

post-2686-0-13949200-1506850985_thumb.jpg

 

Thanks in advance for your expertise advice.

 

Kind regards

—Alex

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Hi joethezombie

 

In fact yes, pressing down on the cap does a little bounce back in return.

 

How could I test the cap to ensure it is working. I am waiting for my first multimeter to arrive. It's a cheapo until I can afford a proper Fluke. Any tips on testing it? Do I have to desolder it to test it? Yes I am truly basic with multimeters. I plan to learn cause it's just so cool to know.

 

Thanks IlikeTech, I appreciate the links.

Edited by Alex
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That big capacitor is probably the very last one that I would suspect as bad.  In my experience, it's always the smaller guys that start leaking.  If you're not having specific issues with the supply, I personally wouldn't change it out.  But IlikeTech is right.  To properly test it, you'd have to remove it.  And at that point, why not just replace it.

Edited by joethezombie
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Iliketech

 

I am curious, you appear to suggest that a cap can be leaky even if it measures ok. This could mean that caps are leaking without knowing it. With the analog/video boards taken out is there a sort of test to check what might be leaking but not yet detectable. I would think that perhaps putting a piece of paper or a toothpick or some other small probe that could absorb a stain could be one way.

 

I have often heard that bulging is a sign of a failing cap, thanks for the added tip joethezombie.

 

I can't test the entire computer until I get the replacement logic board that I just purchased on eBay. Hopefully it will all be ok. This machine is pretty old now, 1998 or so, I imagine changing caps on machines of this vintage is probably a worthwhile investment. Thoughts? 

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Leaky in multiple ways. They can leak under the cap itself, but they can also leak voltage. I don't know much about that but I know it is a problem with tube equipment. I don't know enough to tell you if it is a problem with this. Chemicon makes good caps, so I'm not sure I would worry about that one. I would, however change caps if I has a problem when you get your new logic board.

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