replaceing caps on d865perl

[PCBONEZ]

Re: replaceing caps on d865perl

KZG?

Chemicon KZG have problems sometimes.
The accepted school of thought is that high heat kills them.

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[Phaihn]

Re: replaceing caps on d865perl

This was a while ago now but I've had bad KZG on some MSI [i845 chipset] boards on both high and low sides of VRM. [KZG were not in high and low at the same time on one board. If they had KZG on high side they had MBZ on low and visa/versa.]

KZG looked okay but measured bad.
Boards weren't booting at all so I changed all the KZG out with MBZ and that fixed it.
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The boards had Teapo on them too but I didn't replace those until later after replacing the KZG got them booting again.

I don't think heat could be the issue on the VRM 16v side KZG. Those had lots of room for air flow and the cases weren't small and were well ventilated.
PSU's were all different and checked out okay.

Maybe my experience was a fluke but I still don't trust KZG in anything.

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I see well ive never had any problems with this system till now and its 5 years old i think its just the 2 caps that are bad but i dont know how i would check the rest

[Phaihn]

Re: replaceing caps on d865perl

Chemicon KZG have problems sometimes.
The accepted school of thought is that high heat kills them.

.

ah.. well my system had lots of cooling it was siting at my sisters place turned off for 5 months you think that can couse the caps to go?

[kc8adu]

Re: replaceing caps on d865perl

Fire it up and measure?

put in the cpu/hsf/ram.
hook up psu.turn board on,flip over,and measure voltage across the caps.
bet its 2.5v vdimm.

[PCBONEZ]

Re: replaceing caps on d865perl

ah.. well my system had lots of cooling it was siting at my sisters place turned off for 5 months you think that can couse the caps to go?

Actually I was directing the longer post at KC.

To your question,
Yes.

The systems those MSI boards boards were in were working perfectly fine but then went unused for a few months. (I moved across town and didn't need them right away.) Then when I did need them they wouldn't boot at all. Stone dead.

I've heard similar stories several times where a system worked fine one day and the next morning wouldn't boot -and- in which later it turned out to be KZG problems.

Sometimes KZG work fine but I see problems with them often enough I won't use them.
If I find them in hot spots like VRM or near a video card slot they get changed just to avoid later problems.
If they aren't in hot spots but I have to work on the board for something else anyway I'll change yank the KZG too while I'm in there.

~~
It's actually all because I'm lazy... LOL

I don't mind changing caps but I hate pulling a system apart to get TO the board out so I can work on it. If it's going in for the first time or has to come out I do everything I can to ensure I don't have to tear it down again any time soon.

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[KeriJane]

Re: replaceing caps on d865perl

ah.. well my system had lots of cooling it was siting at my sisters place turned off for 5 months you think that can couse the caps to go?

Actually, caps can go bad from sitting.... but 5 months seems a bit short. I've read about old time radios that sat for decades, and have to have had the caps "re-formed" at 1/2 voltage. (supplied by a light bulb in series with the power cord - wouldn't work for modern PSU-equipped devices)

You don't want to forget that most of our "Low ESR" caps have an expected lifespan of only a few thousand hours, with some boasting of as little as 1,000! (Fuhjyyu TM series). Most have a finite "Shelf Life" too.

Maybe their time was up and they went to that big motherboard in the sky.

Have Fun,
Keri

[PCBONEZ]

Re: replaceing caps on d865perl

KeriJane,

That number in the data tables has nothing at all to do with expected lifetime.

That's how many hours you can run the cap at max temp + max volts + max ripple at the specified frequency and the cap afterwords will still be in spec for ESR/leakage/uF.

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[PCBONEZ]

Re: replaceing caps on d865perl

2000 hours is what MBZ and MCZ are rated for.
And 2000 hours is only ~83 days.

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[Phaihn]

Re: replaceing caps on d865perl

put in the cpu/hsf/ram.
hook up psu.turn board on,flip over,and measure voltage across the caps.
bet its 2.5v vdimm.

i dont have voltage meter . <.>

[Phaihn]

Re: replaceing caps on d865perl

Actually I was directing the longer post at KC.

To your question,
Yes.

The systems those MSI boards boards were in were working perfectly fine but then went unused for a few months. (I moved across town and didn't need them right away.) Then when I did need them they wouldn't boot at all. Stone dead.

I've heard similar stories several times where a system worked fine one day and the next morning wouldn't boot -and- in which later it turned out to be KZG problems.

Sometimes KZG work fine but I see problems with them often enough I won't use them.
If I find them in hot spots like VRM or near a video card slot they get changed just to avoid later problems.
If they aren't in hot spots but I have to work on the board for something else anyway I'll change yank the KZG too while I'm in there.

~~
It's actually all because I'm lazy... LOL

I don't mind changing caps but I hate pulling a system apart to get TO the board out so I can work on it. If it's going in for the first time or has to come out I do everything I can to ensure I don't have to tear it down again any time soon.

.

Yeah i got the hint from the KC at the top of the post.
I realy have no clue about how to go about this so i am getting a used mobo from Ebay as a replacment till i can aford a new board but im still going to get the old one fixed or someone to do it for me and maybe sell it or set up a computer for my mom with it.

[Phaihn]

Re: replaceing caps on d865perl

Actually, caps can go bad from sitting.... but 5 months seems a bit short. I've read about old time radios that sat for decades, and have to have had the caps "re-formed" at 1/2 voltage. (supplied by a light bulb in series with the power cord - wouldn't work for modern PSU-equipped devices)

You don't want to forget that most of our "Low ESR" caps have an expected lifespan of only a few thousand hours, with some boasting of as little as 1,000! (Fuhjyyu TM series). Most have a finite "Shelf Life" too.

Maybe their time was up and they went to that big motherboard in the sky.

Have Fun,
Keri

could be i used to run that computer day and night tehn when i was moving i had to leave it at my sisters place for while.

[Phaihn]

Re: replaceing caps on d865perl

KeriJane,

That number in the data tables has nothing at all to do with expected lifetime.

That's how many hours you can run the cap at max temp + max volts + max ripple at the specified frequency and the cap afterwords will still be in spec for ESR/leakage/uF.

.

Well i think ill just get some replacement caps from the computer store here in town they knew what i needed when i brot it in but didnt have any in stock i just hope they use Rubycon.

[Phaihn]

Re: replaceing caps on d865perl

2000 hours is what MBZ and MCZ are rated for.
And 2000 hours is only ~83 days.

.

lol it woulda burned out in the first year of me having it in that case.

[PCBONEZ]

Re: replaceing caps on d865perl

Is not a bad idea to learn how to replace caps.
-
Besides motherboards and power supplies LCD monitors [and TV's] fail due to caps OFTEN.

[Phaihn]

Re: replaceing caps on d865perl

Is not a bad idea to learn how to replace caps.
-
Besides motherboards and power supplies LCD monitors [and TV's] fail due to caps OFTEN.

yeah my dads lcd tv failed the screen dont come on anymore but theres still sound.

[kc8adu]

Re: replaceing caps on d865perl

i dont have voltage meter . <.>

http://www.harborfreight.com/cpi/cta...emnumber=90899
got a harbor freight nearby?
its good enough for this kind of work and disposable if you goof.

[KeriJane]

Re: replaceing caps on d865perl

That's how many hours you can run the cap at max temp + max volts + max ripple at the specified frequency and the cap afterwords will still be in spec for ESR/leakage/uF.

.

Oops!
UNLESS the cap in question is a Fuhyjju, right?

But it does give a relative indication of expected lifespan, doesn't it?
Also, most are likely to get out of spec shortly after their rated period otherwise they would have a higher rating.

Maybe with a good cap the slow gradual decline into oblivion speeds up after that period....

And with a maybe not so good cap the decline is more rapid?

Have Fun,
Keri

[willawake]

Re: replaceing caps on d865perl

http://www.harborfreight.com/cpi/cta...emnumber=90899
got a harbor freight nearby?
its good enough for this kind of work and disposable if you goof.

yeah gotta have a multimeter. actually i cannot tell the difference in actual usage between my cheap one and expensive one. well except i never test mains with the cheap one.

[PCBONEZ]

Re: replaceing caps on d865perl

Oops!
UNLESS the cap in question is a Fuhyjju, right?

For Fuhyjju you can calculate it by dividing the lifetime number in the data sheet by the uF and then changing the units to minutes.

Oops!
UNLESS But it does give a relative indication of expected lifespan, doesn't it?

A lot of people seem to think it does but not really.

First off it's not a solid number.
- It's an 'at least' number for the whole series. If it were a 'real' number for each cap then every cap in a series would have a different lifetime.
- Also it's a calculated approximation with a HUGE number of variables many of which are assumed or calculated approximations themselves.
[Made up example: The aluminum has 0.8% +/-20% of 'X' impurity which will leach out into the electrolyte at a rate of 1 ppb +/-50% per month and 80% +/- 10% of this will bond with 'Y' in the electrolyte causing 2%+/- 1% per month of the 'Y' to become inert. - All of course assuming the temperature is between here and here.]
-
In other words the numbers going into the math aren't all that accurate,
,,, and there are MANY of them that aren't all that accurate going in.

One of the members came up with an equation to calculate expected lifetime from the endurance life time. Thing is I have seen the same equation at one of the manufacturer's sites. Same problem as before. The variables are assumed because their actual values are +/- ranges and not firm numbers. Consequently they (the mfr site) openly gave the results of the equation a "40% level of confidence".
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In other words the 'answer' you get after doing all the math is +/- 40%.
If the math shows 5 years it REALLY means "3 to 7 years".
If the math shows 10 years it REALLY means "6 to 14 years".
In actual use they could both consistently last 6 years and the math would be exactly correct.

Actual lifetime equations. -> Not very useful.

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[PCBONEZ]

Re: replaceing caps on d865perl

http://www.harborfreight.com/cpi/cta...emnumber=90899
got a harbor freight nearby?
its good enough for this kind of work and disposable if you goof.

I get those things when I want an LCD readout for some project.
It's cheaper than buying just the LCDs.

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