guyperson
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Post by guyperson on Jul 25, 2016 21:40:12 GMT
I've been working on a Saturn that doesn't turn on and on another forum I was instructed to check the capacitors - and indeed, a lot of SMD ones are busted. The thing is, I have no clue what capacity they are and how to find that out. I tried looking for service manuals, but all I found was a June 1995 manual for a model 1 VA0, mine is a model 2 VA9, and they do differ in the capacitor aspect quite a bit.. Any ideas how I could find out what types were used?
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antime
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Post by antime on Jul 25, 2016 22:15:30 GMT
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Post by zyrobs on Jul 25, 2016 22:17:30 GMT
The SMD caps are less affected by aging, it is the electrolytic caps you need to replace, and those are all through-hole on a VA9. And their capacity are clearly marked.
If you buy new ones, make sure you order low height caps, otherwise they won't fit under the EM shield without bending them 90 degrees - and there's only so much space to do that.
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guyperson
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Post by guyperson on Jul 25, 2016 22:56:41 GMT
I forgot to mention, I meant the little ceramic ones, all electrolytic ones seem to be file although I will be replacing those too, because why not. The ceramic ones unfortuantely don't have any writing on them. The only way they differ is color, but different colors only indicate a range of capacitance, not a particular one.
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Post by zyrobs on Jul 25, 2016 23:23:47 GMT
Not sure how you are measuring if they need replacing or not, but if you check the VA0 and VA13 service manuals then you can at least narrow down most of the caps - if they are matching a board marker then they also have the same capacity on later boards.
For ex. CE3 is a 100uf 6.3V cap even on all boards from VA0 to VA13.
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guyperson
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Post by guyperson on Jul 25, 2016 23:39:44 GMT
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Post by zyrobs on Jul 25, 2016 23:58:35 GMT
It's probably not the SMD caps causing that. Can you do a continuity check between GND and +5V or +9V on the board ? If there is any, I'd suggest redoing that solder job. Try to remember which was the last chip you worked on before it croaked, and start with those.
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antime
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Post by antime on Jul 26, 2016 7:11:05 GMT
It's not impossible for ceramic chip capacitors to fail, but it is very unlikely. Don't bother with them unless you actually have reason to believe they're the actual problem. If one really has failed, you need the schematics or a parts list, or have to measure the capacitor from a working board.
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guyperson
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Post by guyperson on Jul 26, 2016 8:42:05 GMT
I see, thanks for all the help by the way since I'm not that experienced. I checked and there is continuity between ground and 5V, so I'll check all the chips I touched up.
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