VOGONS


First post, by Deksor

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I've bought this RTC + floppy controller card recently. At first it made the PSU unable to start. Since this was the sign of a short circuit that I already had with the HDD of the same machine, I started to check continuity on some of the components of the card. I found out that two of these components had a resistance of 0 ohm in both ways while the third one had whatever resistance in one way and infinity in the other. I desoldered the two ones that seemed to be dead and then the computer started up normally. The floppy drive was working, indicating that at least half of the card is still functionnal. However I checked voltage on the holes where the battery was probably soldered before (the previous owner apparently took care of removing an awful battery there, thanks to him !) but it was something like 0.1v so nothing that could charge a battery to hold time. But then I saw that the components I desoldered were connected to the battery circuit.

The attachment IMG_20170614_171338.jpg is no longer available

So the question is in the title : what are these components ? Capacitors ? if I'm correct, then what are their specs ? the only things written on them is "+25" with a "k" between two bars and on the other side is written "106M"

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Reply 1 of 3, by Jepael

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They are tantalum caps, 10uF 25V. They short quite easily when old enough.

Reply 3 of 3, by Maeslin

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Deksor wrote:

Thanks for the specs of these caps 😀 . I'm not sure if I'll be able to find new ones in the same kind of packaging but that should be better than nothing

Considering the traces they're going to, they're likely just power filter caps. Replacing them with regular electrolytics or even ceramics (they do make 10uF ceramic caps) might be an option. Just be mindful of the polarity if going with electrolytics; while tantalums are usually marked by their '+' pin, electrolytics are marked by their '-' pin.

Voltage rating; as long as it's equal or above what the voltage rating of the original was, you're good. Don't go below.