And if you run a 105C cap at 40C you'll get ~ 85 times the datasheet lifetime. So a 2,000 hr 105C cap would last over 19 years. Watch the ripple current of course !
Interesting point there. One decoupling cap on a mobo of mine near the graphics card slot was visibly bulged whereas others weren't. I imagine it was hot air being blown onto it by the GPU fan.
Graham
In article , Spehro Pefhany writes
Not from electrolytic caps, which was kind of the point. Even Panasonic specify only 10k hours for their top of the range electros.
I guess that would be a rather serious problem if the temperature inside your computer case averaged 105°C = 221°F.
In article , Spehro Pefhany writes
Seen a modern mainboard recently? Voltage regulation MOSFETs with heatsinks on, some with their own extractor fans? Heat coupled to the capacitors by a few millimetres of thick copper PCB trace for excellent heat conduction?
But isn't that at "high" temperatures, or some other extreme operating condition?
Certainly.
Have you put a thermocouple on the capacitors?
AT RATED TEMP and RATED RIPPLE CURRENT. Rarely found in combination except by bad design, and it does happen sometimes.
You can get far better by de-rating. Rule of thumb is to reduce the temp from rated value by 10C and double the lifetime etc etc.
Graham
Yes.
Grham
Point 1: You can ventilate your case and CPU far better than 'normal' methods.
Point 2: leave the side panels off like I tend to do !
Graham
You need a themocouple and a suitable meter for that ! ;~)
Graham
S*it, I'd generally be happy with 2000 hours MTBF.
I do, but that's mostly to make it easy to perform full backups. The machine run coolers, though it spews more RF, which keeps atomic clocks in the same room from synching.
By the way, check the CPU cooler occasionally. Mine hadn't been cleaned since I bought the computer over eight years ago, and you cannot believe how clogged with shmutz the heat sink was.
Not a problem for me.
I clean them moderately regularly. Plus I don't operate in a very dusty environment.
Gragam
Nor do I. This wasn't dust -- it was more like gobs of sub-microscopic carbon particles.
Never seen that. On the CPU cooler itself you mean ?
Grham
Yes ! Gigabyte got bitten hard by that and the fake motherboard scam.
Really? ;-)
Of course many, if not most, portable multimeters have type K thermocouple inputs (of dubious accuracy, but good enough for this sort of thing) and many are supplied with a bead thermocouple.
Less than 12 weeks? You have a bright potential future with Samsung, HP etc.
Funnily enough, often some of the cheapest ones have the thermocouple input but I used to keep a supply of type-K themocoouples anyway. I like keeping an eye on temps.
Graham
On the heat-sink. It reminded me of the black stuff that comes off a CRT faceplate. Only a lot more.
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