Question about 85c caps vs. 105c caps

[Wester547]

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

Do you think a 1200RPM case fan would be too much for that, or do you think it could be pointed to the motherboard without disrupting upon the airflow of the PSU fan and the CPU fan in tandem?

It is a bit small though, so I don't even know if there's room for another fan. That is to say, the case isn't small, but the motherboard somewhat is. As an update, I loaded the CPU to 100% last night for an hour in a half in 3D full acceleration. It was rather cold weather, however (for California), being at around 48F, so the CPU was only up to 44-45C at full 100% load, and the motherboard and auxiliary ranged from 35-37C, with the hard drives at 33C and 35C respectively (the ST3250824A and ST3160023A). After doing that, I shut it down and took off the side panel, and felt the motherboard, along with the RAM, capacitors, CPU, etc. The 105C capacitors did feel somewhat warm after that, but they're Polymers and 105C Nichicon HDs so I know they're good. As did the CPU and GPU (even colder, though) - slightly warm air could be felt around that area, though nothing grave. To my relief, the 85C caps felt significantly cooler, even though they were right next to the RAM, which also didn't feel hot. I guess the RAM might not be a problem because it's in a large enough case not to heat up too much.

I was pondering about the computer automatically powering up. Can't that also be the resulting consequence of a dead CMOS battery (as it is unable to retain the last state the computer was in so automatically powers on the system with the default BIOS values - in the BIOS, it is set to automatically power on after it loses power)? It does beep two times as the error comes up. And would it be seen as dangerous for any of the components to use the power switch in the back to power the system on and off by contrast to the case switch in the front? (what would usually be used)

And right, it says VR(M), not VRM. ^^; And if a capacitor doesn't look like it's impeccably aligned to the board, does that mean it's irrevocably bad (I know the main Badcaps page says something to that effect, but I'm just curious)?

[PCBONEZ]

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

Do you think a 1200RPM case fan would be too much for that,

Just 1200RPM doesn't tell me anything.
It's CFM that matters and that varies with: RPM, diameter, thickness, number of blades and pitch/shape of blades.
You want at least 40 CFM for a side fan and more is lots better.
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Probably take two fans but if you can get 100 CFM [filtered] going in the side you can usually get rid of the other case fans because the positive pressure will push air 'out' through where they were and that keeps inside the case cleaner.
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[PCBONEZ]

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

I was pondering about the computer automatically powering up. Can't that also be the resulting consequence of a dead CMOS battery

No.
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When you push the start button it temp grounds a pin on the chipset and that initiates start-up. [It's not a full ground. It's called to 'Pull Down'] The pin is normally powered [aka 'Pulled Up'] by +5vsb through some other circuitry. If +5vsb drops the volts on that pin can go low which looks to the chipset like it's grounded.
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[Wester547]

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

Could it be a result of something corrupted in the BIOS then (or the chipset)? I know the power supply isn't bad. The system started doing this before the PSU was replaced. Could it also be a broken switch in the front? Not laying doubt to your answer, just asking. ^^; This could be something the other dying PSU ruined in the setup as well.... right?

And another thing about capacitors is that I would think that CPU usage would affect the capacitors around it since some of them are voltage regulators, and high CPU usage is known to be a problem with defective capacitors.

[jamesbo]

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

I recently bought a surplus Intel 845gvsr motherboard. Everytime you turned on the power strip the board would start up. The problem was a dead cmos battery. The default in the bios is "boot after power failure". Once I replaced the cmos battery and changed the bios setting, it would stay off until the power button push pressed.

[Wester547]

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

Thanks for that helpful inkling of input. That sounds like a coherent explanation to me. Of course, it could be the the pin on the chipset as well, but it's hard to say.

[PCBONEZ]

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

I recently bought a surplus Intel 845gvsr motherboard. Everytime you turned on the power strip the board would start up. The problem was a dead cmos battery. The default in the bios is "boot after power failure". Once I replaced the cmos battery and changed the bios setting, it would stay off until the power button push pressed.

They'll all do that if you cut AC line power and the battery is dead.
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On modern boards the CMOS is powered from +5vsb through a step down.
The battery only powers it when there is no AC and hence no +5vsb.
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Basically if you never cut AC then you won't be running the battery down.
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[PCBONEZ]

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

And another thing about capacitors is that I would think that CPU usage would affect the capacitors around it since some of them are voltage regulators, and high CPU usage is known to be a problem with defective capacitors.

Capacitors are not voltage regulators.
They smooth and filter the output of voltage regulators.
[Ummm, most on a mobo anyway. They have other jobs in different apps even on a mobo.]
Loading on the CPU has no affect on caps *in that way* because the CPU power doesn't go -thru- them. [It is DC.]
What heats caps is Ripple which is a semi-random AC.
Ripple is the 'noise' [voltage spikes] made when transistors [in this case in the CPU regulator aka VRM] turn on and off. In a CPU VRM one set of transistors lowers voltage by intermittently connecting to ground [on-off very fast] and another set raises voltage by intermittently connecting to +12 [on-off very fast]. The final voltage to the CPU is where the raise and lower balance out. The transistors switch on-off something like 50k-100k times a second thus the ripple frequency there is 50kHz to 100kHz.
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[PCBONEZ]

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

Could it be a result of something corrupted in the BIOS then (or the chipset)? I know the power supply isn't bad. The system started doing this before the PSU was replaced. Could it also be a broken switch in the front? Not laying doubt to your answer, just asking. ^^; This could be something the other dying PSU ruined in the setup as well.... right?

No. BIOS won't do that.
The BIOS code [program] in CMOS does not run until -after- it starts.
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A bad switch could do it.
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And a bad small cap could do it by not holding it's charge or by being partially shorted. [Not likely to be a large cap in any of those circuits.]
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If you have a chip with a "Wake On" function [like wake on LAN, etc...] that has gone dodgy then that could be switching it on due to a fault in it's circuitry. (Including caps.)
All a 'Wake ON" function does to start the system is pull the pin on the chipset down via a different path.
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[Wester547]

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

I should be clearer - just before the PSU was superceded, the system would automatically power on but I would receive no CMOS error. After switching power supplies, the error came to bear. Great information. I do think given how old the motherboard is that the CMOS battery could be the culprit, but the only way to tell is to move the 3-pin (clear/reset CMOS) jumper or get a new battery. The only thing that only concerns me is whether the VR capacitors will last and whether or not a capacitor that doesn't look aligned to the board immaculately (even in the slightest) might be a problem... also, is there a risk in using the back on/off switch in lieu of the front one to power the computer on and off?

[PCBONEZ]

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

The only thing that only concerns me is whether the VR capacitors will last and whether or not a capacitor that doesn't look aligned to the board immaculately (even in the slightest) might be a problem...

Can not tell you.
Sometimes they lean then when they are pushing the bung out.
OFTEN they simply were installed crooked.

I do think given how old the motherboard is that the CMOS battery could be the culprit, but the only way to tell is to move the 3-pin (clear/reset CMOS) jumper or get a new battery.

CMOS Reset won't help you.
All that does is short the battery long enough to wipe BIOS settings.
[Procedurally you turn off the +5vsb supply first. AKA Remove AC power.]
If the battery is dead the settings are already wiped [reset] as soon as you turn off +5vsb.
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I suggest you check the battery voltage with a meter or just get a new battery.

is there a risk in using the back on/off switch in lieu of the front one to power the computer on and off?

The switch on the back is like unplugging it from the wall. To the system it the same as a power outage.
Not safe unless the system is already shutdown because the hard drive might be busy doing a maintenance task.
The one on the front panel does not denergize standby power [+5vsb] so it isn't 'off' like you are thinking of off.
It's not off-denergized, it's actually just in standby. It also lets the hard drive(s) finish before it 'kicks in' and shuts it down.
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[Wester547]

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

The system is always shut down before I turn the switch in the back off. Would that be safe?

[PCBONEZ]

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

The system is always shut down before I turn the switch in the back off. Would that be safe?

Yes.
That's the proper way.

[Wester547]

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

Would it be safe for the computer to automatically power on after the switch in the back is on?

[PCBONEZ]

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

Would it be safe for the computer to automatically power on after the switch in the back is on?

Yes.
That's why it's a setting in the BIOS.

[PCBONEZ]

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

You don't know how to solder do you....
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[Wester547]

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

I didn't say that, I just wanted to be sure that I don't damage anything inadvertently. Thanks for the info.

[PCBONEZ]

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

It's pretty clear you are new to all this stuff.
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I recommend you get a new system [maybe a refurb Dell Core2Duo but not a mini-case] for your important stuff and then use this one to learn on.
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[Wester547]

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

I am new to a deal of it, which is why I came here. I find this place a great reservoir of knowledge. And I do already have other systems I can use, I was just curious, as stated. ^^;

[PCBONEZ]

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

In that case I recommend you replace the VR and see if it helps.
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