aurgathor
Member
Last Activity: 09-13-2024, 08:14 PM
Joined: 05-09-2012
Location: Lynnwood, WA
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To me that looks like *one* bad cap in one particular product. Or in the XBOX, but I have not seen any indication that this is a widespread issue. I do know that with regular caps, certain years from certain manufacturers can leak, but that doesn't apply to all caps. I have at least a couple of devices (i.e. dash cam) with a supercap, and had zero issue with them. I know that's a very small sample size, but on the other hand I've had bad cap issues with probably over 2 dozen pieces of equipment over the years.... -
Evidence please showing that this is a widespread issue....Leave a comment:
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Super caps are good when they need to provide power for a short time [seconds, maybe minutes], such as in a dash cam after the ignition is turned off.
They need to power it long enough to close files and do an orderly shutdown -- which shouldn't take more than a couple of seconds. Unlike batteries, their capacity won't change much, so they're a better option in that particular use.Leave a comment:
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G & F may be used to indicate tolerance (2% & 1%) but I don't think that's the case here. Your capacity and voltage guesses look correct for 1..4.
As for the typical ratings for those small SMD caps -- see if any one of them has some kind of marking. Alternatively, if you have a capacitance meter, you can desolder some and measure them. My guess is that most of them, are probably in the 10 nF to 100 nF range.Leave a comment:
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I would go with some 4V caps -- here are some US (digikey) examples: [url]https://www.digikey.com/en/products/filter/aluminum-polymer-capacitors/69?s=N4IgjCBcoOwEwBYqgMZQGYEMA2BnApgDQgD2UA2iHAGzUCcArNSMXABxgAMAzAy1QjZs4MEAF1iABwAuUEAGVpAJwCWAOwDmIAL6tOCOshBpIWPEVIUQwzgAIArQDFxU2ZBABVNSukB5dACy%2BJi4AK5K%2BDp6MIbQxhg4BMRkkJQItgBqLiAycl4%2B-kEh4ZG6IAC0cEYmyqEWKZR8YtplVanGmJKYKD4kSuLaQA[/url]
However, if you want to use the 6.3V cap from the same series, that should probably work, too.https://I would go with some 4V caps...4kSuLaQA[/url]Leave a comment:
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In a laptop a good portion of the caps will be filtering capacitors, so there should be very little in pF range. Since mobos often have duplicate caps on the same voltage rail, you can get a pretty good approximation about its capacity range by looking at the others.Leave a comment:
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Recommended replacement cap & voltage
I have an older SFF Dell (GX620) that I want to turn into a router, but it has a few *really bad* looking electrolytic caps (4x 2200uF 6.3V & 1x 1800uF 6.3V) that need to be replaced first.
Questions:
1. What are some the recommended caps for these values? (I will probably order from digikey)
2. Looks to me there is enough space for slightly bigger caps -- would I gain anything with respect to longevity by using 10V caps instead of 6.3V caps? (I guess I probably need to look at the current voltage with a scope since I do not know the nominal voltage of that r... -
Re: Dell Optiplex GX280 no boot and fan going crazy
Good info, thanks. Thing is, I'd like to find out before recapping if it's the caps or cracked solder balls, so I think I'll just "spring load" the HSF first to see if that makes any difference.Leave a comment:
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Re: Why do they use a 10V cap instead of a 6.3V cap?
While I'm not sure where exactly those 50V pulses come from, rectified AC before filtering can have peaks I think about 1.414 times higher than the nominal voltage, and that's about 7V peak for 5V nominal, and the cap should be rated for that.Leave a comment:
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Re: identifying SMD ceramic capacitor damage
SMD ceramics themselves are fairly reliable, but if they do fail because of spikes or overvoltage, chances are good that something else got fried, too. When they do fail w/o overvoltage, that's often physical because of stress levels, or the failure is caused by other external factors, often related to soldering, etc.
You could probably test them with a good capacitor tester, but I think the fault lies elsewhere.Leave a comment:
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Re: Dell Optiplex GX280 no boot and fan going crazy
I measured (in circuit) the 1800 uF caps (9) next to the CPU socket, and depending on frequency, they're about 1550 - 1600 uF. Definitely less than 1800 but within 20%.
The 1000 uF/16V caps are about 850 uF each, also a little on the low side, but also within 20%.
Kinda hard to figure out what to do.... it's not like a 1000 uF cap measuring 125.Leave a comment:
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64 meg NVIDIA AGP card
Had some issues and pulled the card, but I can't decide if those 470 uF 10V caps are bad or not.
Did anyone replace caps like those?
Oh, and for some extra 'fun', they are surface mounted...
TIA... -
Re: Checking ESR and Capacitance
For electrolytics, there's no such thing as 'normal tolerance'. You need to consult the data sheet.
Back in the 80's, lots of electrolytics had a tolerance of -50% +100%, but due to advancements in technology, I don't see them much any more.
As for whether a higher value is safe or not, that depends a lot on the circuit. In many cases much higher values will be OK, other times they can cause problems....Leave a comment:
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Re: Dell Optiplex GX280 no boot and fan going crazy
I did not check them with a meter, but I do not see bulging or leaking caps in the PS.Leave a comment:
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Re: Dell Optiplex GX280 no boot and fan going crazy
I have a small desktop GX280 that is mostly dead. I thought it was a cap problem, but after reading this thread there's another possibility, a cracked solder under a BGA, and I don't think I can do much about that.
The caps I've seen in repair kits are 1500uF 6.3V and 1800 uF 6.3V, and there are nine of the latter next to the CPU socket.
Did anyone ever successfully repair this board (see attachment) by recapping? Which caps were replaced? How did the caps fail?
In addition to the 9 caps next...Leave a comment:
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