Question about 85c caps vs. 105c caps

[japlytic]

Re: Question about 85c caps vs. 105c caps

[In general] Jap companies are king at QA. . CH & TW companies are king at pinching pennies.

The companies which outsource and rebadge units from Taiwan and China could also be pinching pennies.

[Wester547]

Re: Question about 85c caps vs. 105c caps

I hate to bump this thread but I figure this thread deserves an update.

There are bad capacitors on that motherboard.... three HMs with a date code of Week 20, 2002 sit by the CPU.... it's funny since I always heard people say the D845PEBT2 was not affected. Maybe the earlier ones weren't since that particular PC was bought in January of 2003. Still too bad. I know it can be recapped but I dunno if something that old is worth the effort, especially considering the board has already suffered slight damage from the failure of the last two PSUs. Kinda feel silly though that I squandered people's time asking so many questions about a board whose problem was right under my nose all along. ^^; Hard to believe it lasted at least over 9,000 hours but more likely 11,000+.... probably because it's not a thin case like those of the Dell Optiplexes.

[Wester547]

Re: Question about 85c caps vs. 105c caps

60C would be okay in cold weather?? ^^; For a 105C cap... because that's how it felt at the top in weather that was 60F (at 100% load on the CPU, which was at around 50C, for about an hour). It only concerns me that it felt as such in cold weather. But if touch isn't a good test of heat, that means that touch is not a reflection of the temperature of the part (necessarily)?

[PeteS in CA]

Re: Question about 85c caps vs. 105c caps

The threshold for "too hot to touch" is somewhere around 55C-60C for most people. 60C is not bad for 105C cap. But touch is not a good test for whether the part is too hot to have a long useful life.

[Wester547]

Re: Question about 85c caps vs. 105c caps

That coheres for me. I appreciate the info. But is it supposed to feel too hot to touch at the top of the capacitor, ever?

[PeteS in CA]

Re: Question about 85c caps vs. 105c caps

Assuming the heat is not radiated from nearby components or conducted from nearby components through copper traces ...

The terms "low impedance" and "low ESR" are used here more or less interchangeably,but they are not identical. The impedance of a cap is the vector sum of the ESR, the ESL reactance and the capacitive reactance (the latter two partly cancel each other, with the net reactance, inductive or capacitive, being frequency dependent). ESR = Equivalent Series Resistance; ESL = Equivalent Series inductance (L). The ESR dissipates power when ripple current flows through it, the formula being (I)(I)(ESR). So if you have 15 milliohms ESR and 3A of ripple current, that little 10mm diameter capacitor is dissipating about .135W. And the only good heat dissipation path is through the top (for a lytic with a plastic sleeve).

[Wester547]

Re: Question about 85c caps vs. 105c caps

As well as the Chemicon PS capacitors.... but I noticed that the top of the capacitors are too hot to touch, period (only when the CPU is at 100% load; when at 0-5% load, they are hardly warm).... what does that mean?

[Wester547]

Re: Question about 85c caps vs. 105c caps

I don't mean to bump again, but I do have another question that has been encircling my mind. ^^;

Are capacitors by the CPU supposed to get hot when the CPU is under full load? In hot enough weather, too hot to touch? In my case, I mean the 105C (Nichicon HD and they're gray) capacitors left of the CPU. One, in particular, gets noticeably hot even when the CPU is only at 49C for an hour. At 53C it gets almost too hot touch, which leads me to be of the belief that it would be too hot to touch if the temperature were any higher for a prolonged span. I know capacitors release heat, but are 105C capacitors next to the CPU (one, in this case, in particular, is hotter than the others) supposed to be hot? Could it be either A) that the PSU in there does not have 80% efficiency (it's a 300W Hipro so I doubt it has that) so it's giving off more ripple or B) that the CPU fan expels heat to the left, where the vents are, and that the 105C capacitors that are getting hot are left of the CPU? I know those capacitors are rated at 105C but I have a drudging time believing that a capacitor could last when it gets too hot to touch in hot weather (when the CPU is at 100% full load). One 105C capacitor gets hotter than the CPU heatsink itself does (and hotter than the air the PSU fan is pushing out, along with the CPU fan), so....

[selldoor]

Re: Question about 85c caps vs. 105c caps

necroposters going to eat my threads!

BUT its his thread???

I reckon his questions have fried PCbones' brain so he has gone into hiding.

[Wester547]

Re: Question about 85c caps vs. 105c caps

^^;

It also fried the front USB ports (or at least the chip that controls them along with the 1394 port), but putting in a USB 2.0 card has rectified that for now.

[Uranium-235]

Re: Question about 85c caps vs. 105c caps

necroposters going to eat my threads!

[Wester547]

Re: Question about 85c caps vs. 105c caps

I don't mean to make too much of a necropost, but I thought I'd give an update whilst asking another question of sorts. ^^;

Firsts of all, the "BFG 450W" PSU in the system ended up being of the GS series which means it was tripe and Huntkey (a rebrand of Huntkey's V-Power "450")... and after 1 year and 8 months of 300-350W service (12/7), it not only died but took the ST3250824A with it (but thankfully only that, which may expound why I was seeing higher temperatures on it before it died). The system would not boot when I tried it a couple days ago - PSU fan spun, LED came on, CPU fan spun, graphics card fan spun, keyboard flashed, DVD-RWs flashed, HDDs spun up (the ST3250824A can still do that much but it will not do anything else other than be recognized and spin up/down), but that was it. So.... I found an old 300W Hipro (HP-P3527F3, only 9 months of 12/7 use) lying around (a 300W FSP300-60BTV was the original PSU that came with the machine, but its filtering capacitors, I believe, started going bad, as stated by others before me in this thread). I swapped PSUs and the system runs fine again, only with the ST3160023A and slightly augmented temperatures (this PSU's fan does not ventilate the case as effectively but oh well).

Also, I noticed PCBONEZ posted this in another thread of talk, so if I may ask:

Nichicon VR [85C @/2000Hr] start going bad after about 4-5 years 24/7 in poorly cooled cases.

Would this be equal to 8-10 years of 12/7 use (or is that too general a question ^^; )?

[Wester547]

Re: Question about 85c caps vs. 105c caps

Well, given that this is an AGP 4x slot (and the 9500 Pro is an AGP 8x card), I can't imagine the TDP being more than 50w... maybe 41w, even? Or even a tad lower.... I don't think that should produce that much heat.

[Wester547]

Re: Question about 85c caps vs. 105c caps

I think extra fans would help, not arguing that. But, the case is very cluttered as it is with components, and the motherboard is rather small (it only had two slots for the RAM). ^^; And I've cleaned the case very thoroughly - it's dust free. But I'm not sure about the TDP of this card. I can't find the TDP for the R300 anywhere, though I will continue searching. And it isn't just the heatsink that feels hot - the RAM chips on it feel very hot as well (and as aforementioned, they have no cooling). Underclocking the memory will definitely make a difference in thermal output. And yeah, I know, that's why I'm not running it with the side panel off all the time, only in especially hot weather.

[PCBONEZ]

Re: Question about 85c caps vs. 105c caps

I agree that the heatsink should be hot... but too hot to touch in cold weather? Doesn't that mean the chip is getting too hot? Underclocking did make a tangible difference though, which is good enough for me. But I also noticed that the CPU and auxiliary/motherboard run 4 degrees cooler (in celsius) when the side panel is off.... would this convenience the capacitors as well, or would more 'natural' airflow be attained by keeping the side panel on? ^^; I know people said in this thread to leave it the way it was, but a 4 degree drop in temperatures...

Fasten a heatsink to a 60 watt bulb and turn it on for a half hour.
Do you think the heatsink will be hot to touch?
Same thing..
.
4 degrees isn't going to matter much unless you are right at some limit.
Open cases get dirty inside. Dust bunnies.
If I wanted to get temp down I'd put a filtered fan in the side panel like I said before. [If that was in this thread...]
.

[Wester547]

Re: Question about 85c caps vs. 105c caps

I agree that the heatsink should be hot... but too hot to touch in cold weather? Doesn't that mean the chip is getting too hot? Underclocking did make a tangible difference though, which is good enough for me. But I also noticed that the CPU and auxiliary/motherboard run 4 degrees cooler (in celsius) when the side panel is off.... would this convenience the capacitors as well, or would more 'natural' airflow be attained by keeping the side panel on? ^^; I know people said in this thread to leave it the way it was, but a 4 degree drop in temperatures...

[PCBONEZ]

Re: Question about 85c caps vs. 105c caps

A heatsink's job is to 'sink' (carry away) from the chip underneath it.
If the chip underneath it is hot then the heatsink should be hot.
.
If the chip is hot and the heatsink isn't then you need to replace the thermal pad or paste because the heat isn't transferring.
.
If the chip isn't hot then it's not under full load and the heatsink shouldn't be hot either.
.
If you do a bit of web searching you should be able to fine the TDP (Total Design Power) of your video chip.
- Or your motherboard chips or any other chip for that matter.
It's not always easy to find but it should be 'out there' somewhere for most chips.
.
TDP is (effectively) the max heat in watts the chip should be giving off under full load.
If it says 60 watts TDP then at full load that little tiny chip is giving off as much heat as a 60 watt light bulb and the heatsink should probably burn you.
.
Sometimes you can find max case temp for IC chips which is good info too.
Some chips can handle loads of heat without a problem, others not so much.
.
.
This will give you some idea of how much the TDP for video chips varies.
I don't see your chip listed but it (or one close / in the same family) should be somewhere.
http://www.geeks3d.com/20090618/grap...-tdp-database/
.

[Wester547]

Re: Question about 85c caps vs. 105c caps

Nevermind... ATI Tool lets me underclock it. ^^; That should help.

[Wester547]

Re: Question about 85c caps vs. 105c caps

I hate to bump this thread, but I ran the system at full 3D load again and put my finger on the 9500 Pro's heatsink and it was somewhat scorching (though the RAM chips on the card did not feel quite as hot and they have no cooling) - almost too hot to touch. This is in cold weather. Since the people here are so knowledgeable, are heatsinks supposed to feel so hot (heatsinks that are mounted onto devices, at full load)? None of the other heatsinks on the motherboard feel hot. I know that probably means it's probably transferring lots of heat, along with the fan, which is good. But if the card is overheating, wouldn't it be imprudent to leave it in a system with caps that won't survive hot hardware? I know the card has a fan to remove heat quickly enough that it won't affect the rest of the system so much, but I worry with an excessive temperature from the card in somewhat cold weather. I understand that the fan could be worse for wear at this point, though, and you wouldn't know it because it's a nigh silent fan.

[PeteS in CA]

Re: Question about 85c caps vs. 105c caps

Electrolytic mostly fail open. Tantalum and ceramic fail shorted.

Just an addendum, monolythic ceramic caps tend to fail short (or low resistance); I have seen a few that opened or had high resistance at one of the terminals. Old-style disc ceramics tend to fail open. I have seen a few lytics fail short, after many hours of torture-testing (at ripple currents that once or twice caused the lead wires to open like a fuse).