I suspect capacitance will be a smidge less due to reduction in separation between some of the layers, but it's not indented severely, so I suspect it's safe.

Munx wrote:

I have a question about solid capacitors. […]
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I have a question about solid capacitors.

I'm replacing a couple of caps on this Radeon 8500 LE (it got quite a beating as the guy who sold it had it just rattling about in a box with a bunch of other cards) and one of them seems to have an inward dent in them:

P_20170826_104352.jpg

Are these types of caps still able to work or should I replace it? If so, I assume its 47uF 6V? What does the 17 stand for?

It's not a solid capacitor, it's a standard non-solid electrolyte capacitor. 47uF 6V. 17 is some kind of manufacturing traceability code or some sort of description of cap series.

I would not worry about a slight dent, but that looks like it's been a pretty sharp object, is the aluminium case punctured?

Also, if you did not notice, I'd be slightly more worried about the coil L7, it's missing a part of it's top. I won't try to guess if that's OK or not.

Thanks for the info. The dent is slightly bigger than it appears in the picture, however it's not punctured. Guess I'll have to give the card a test to find out if it works (after I replace the other cap that has basically been yanked out half-way)

The coil seems to be okay and only the plastic bit is broken off.

Munx wrote:

The coil seems to be okay and only the plastic bit is broken off.

Except it's not plastic, it's the magnetic core material made of ferrite.

I see. Sorry If I'm going off topic too much with my n00b questions, but what sort of resistors are these? I want to order some and don't even know what to look for.

Googling the card it shows the broken ones here have "3R3" and "100" written on them. Do these types have a specific name so I can find the type that fits?

SMD resistor packages (and sizes) are standardized. You just purchase the resistance and package type you want from Vishay, etc.
http://www.radio-electronics.com/info/data/re … md_resistor.php

Okay, dumb me, I was actually asking about inductors... (the ones with the broken tops in the pictures)

Munx wrote:

Okay, dumb me, I was actually asking about inductors... (the ones with the broken tops in the pictures)

I don't know the name for that particular inductor package type, but do try to search for suitable package type from manufacturers such as Coilcraft, Murata, Vishay. Or retailers such as Farnell, Digikey.

But it is impossible to know other ratings of the inductor, on the part it only reads the inductance (3R3 means 3.3 uH for example).
You still are missing things such as DC resistance, saturation current and RMS current.

Edit: Also, is that big thru-hole electrolytic cap near 100uH inductor L7 bulging, or does light just play tricks?

Jepael wrote:

I don't know the name for that particular inductor package type, but do try to search for suitable package type from manufacture […]
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Munx wrote:

Okay, dumb me, I was actually asking about inductors... (the ones with the broken tops in the pictures)

I don't know the name for that particular inductor package type, but do try to search for suitable package type from manufacturers such as Coilcraft, Murata, Vishay. Or retailers such as Farnell, Digikey.

But it is impossible to know other ratings of the inductor, on the part it only reads the inductance (3R3 means 3.3 uH for example).
You still are missing things such as DC resistance, saturation current and RMS current.

Edit: Also, is that big thru-hole electrolytic cap near 100uH inductor L7 bulging, or does light just play tricks?

Must be the camera as none of the caps are bulged.

I'll still be picking up some caps from a store near where I live, I guess it would be a good idea to ask around there.

Jepael wrote:

I don't know the name for that particular inductor package type, but do try to search for suitable package type from manufacture […]
Show full quote

Munx wrote:

Okay, dumb me, I was actually asking about inductors... (the ones with the broken tops in the pictures)

I don't know the name for that particular inductor package type, but do try to search for suitable package type from manufacturers such as Coilcraft, Murata, Vishay. Or retailers such as Farnell, Digikey.

But it is impossible to know other ratings of the inductor, on the part it only reads the inductance (3R3 means 3.3 uH for example).
You still are missing things such as DC resistance, saturation current and RMS current.

Edit: Also, is that big thru-hole electrolytic cap near 100uH inductor L7 bulging, or does light just play tricks?

I would expect similar ratings given the package constraints. Geometry, core material, and coil alloy should all be very similar.

I have a question. Is it safe to replace polarized capacitor with a non-polarized one?
I want to do it to because with my simple tools I like the long legs of non-SMD parts.
Judging by position on the card I think this one is just smoothing power to memory and it should be safe. But I know little, so now I got cold feet before powering it.

smeezekitty wrote on 2015-06-17, 18:25:

As I said before, it depends but you can generally go a reasonable amount higher in filter applications. Don't go too high thoug […]
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fyy wrote:

OP here, thanks again for the responses guys. One more thing, why is it wrong (as a general rule) to replace a capacitor with one that has a higher capacitance? Wouldn't storing more charge be better generally (like having a larger battery)?

As I said before, it depends but you can generally go a reasonable amount higher in filter applications.
Don't go too high though. If it is too big, it will have a large inrush which can damage upstream circuits.

Don't change capacitive values in resonate or coupling circuits unless you really know what you are doing.

What they don't tell you is that VRM filter caps don't depend on capacitance at all. Electrolytic and polymer caps are designed to have resonance at or around 100khz, the typical operating frequency of switch mode converters. Output ripple is then proportional to ESR.

Remember, all capacitors also behave inductively just as all inductors have capacitive properties.

Jepael wrote on 2017-08-25, 19:25:

gdjacobs wrote:

Jepael wrote:

I already explained it can throw off a control loop, like a switching power supply regulator feedback loop. Some switching power supply chips have a limit how large (or small) a capacitance you can put at the regulator output or the output voltage won´t be stable, it could start to oscillate or something, perhaps responding slower to quickly changing load currents, etc.

Even substituting different ESR can result in a feedback circuit not behaving properly. The best bet is finding an approximate match for ESR and capacitance. Ripple, temperature, and lifetime can all be up specified freely.

My quote from two years ago? But you are correct and I think I've said in some other thread too, but for example LDO regulators require ESR to be within certain limits (not too high, not too low) for them to work properly.

We might be reading the same material. I found the following article after reading a TDK application note on using MLCC caps in substitution for 'lytics.
https://www.industrial-electronics.com/switch … -supply_7f.html