Intel D845GVSR Recap - No boot

[PCBONEZ]

Re: Intel D845GVSR Recap - No boot

I found some Tayeh with the Teapo six line stamp.
(the double Y with every other line short)
I think Tayeh were OEMed by Teapo.

[i4004]

Re: Intel D845GVSR Recap - No boot

>Capacitance is measuring amount of cap in farads ONE THING, we don't measure for that, we measure ESR to determine the overall health of electolyte function containing within electroytic capacitor as this is what determines function of the circuits.

by looking at your paragraph capacitance doesn't matter for us at all, does it?
so we may as well put a piece of copper wire there instead of cap, right?
it does qualify, according to your words: we don't measure capacitance, only esr.
so we'll have low esr(as copper is a good conductor)....as for lack of capacitance...who the hell cares, as we don't measure it....heh...

also, you say we measure esr: so why did you discard tayeh? it has good esr...
according to that paragraph of yours he can be sure tayeh is good replacement, as it has ok esr....
otoh, i told him to try to DOUBLECHECK those tayeh's ie to check their capacitance too...chances are it's ok if esr is ok, but if he can measure capacitance too, even better...



>We know i4004 is promoting fragmentary knowledge

nope, fragmentary knowledge was demonstrated by you just above, where you say capacitance doesn't matter....

>I have been there many times where I seen the problems with bad caps caused even acceptable ones, (i4004 implied intention of using medium quality capacitors) were not doing the job at all in most electronics.

what you're saying is in stark contrast with the known fact: those caps that are preventing the circuit from functioning correctly have substantially higher esr than is normal.

according to you, only caps with lowest possible esr will be ok for circuit to work.
i call BS on that and simillar statements.
it's just not true.
it is not true for low esr applications, and it's not true for general purpose applications where esr is not as much important.

what i've told you, and what i've measured , is that if you put 2 gp caps together, you'll get the esr that goes all they way down to values usually associated with low esr caps...
what's more, in a lot of cases you can put ONE gp cap instead of low esr cap, because circuit can take it BECAUSE the problems appear at higher esr levels, ie much higher than even normal functioning gp cap will exhibit...
(for how long will this circuit work with that gp cap is not something i was discussing, be aware of that...)

i never said this is a guaranteed way to fix a mobo, but something to try if you can't find better replacements, so please don't play dumb: i always accentuate that if you have a source for top grade low esr caps, sure buy those..if not, tinker with what you have.
gp cap with esr of 0.10ohm surely won't break the mobo, because problems occur only at higher esr values....

also, did you not read what will said in this thread?
he said
"failed is usually over 1.0ohm (i had some bulging at 0.26 though)"
you're aware what that means, right?

when it comes to this case, my prediction would be that caps you're suggesting he buys won't change anything. he already has caps what should work. again i add, it would be good if he could check the capacitance to be 100% sure....
with esr alone he's probably 90% sure, yeah....

also, i'll ask you again
>in the end, i would politely ask you to point me to one such "ill-advised" comment, as you've put it. also with explanation why is it bad.
thank you very much!

if you can't provide that you're badmouthing me for no good reason....
again i'll repeat something i said anytime i was discussing this:
those who can get best possible caps should do so, those who can't should tinker with what they can grab....
so again, don't play dumb, and don't skip those words like you're doing thus far...

attack me when you have a reason, not in this dirty way...

linuxguru:
>The Tayehs (now a division of Teapo) probably weren't too bad when new, but if they're pulls from a dead mobo, all bets are off. They might work OK in low-current bypass applications, but not on Vcore.

that's just a lousy guess....we don't need to guess if we have esr meters, and this guy has said esr of these tayehs is good...
you can't be positive these caps don't work on vcore, quite the opposite, if the esr is what he says it is, chances are it works...


but otoh chances are some semiconductor was desrtroyed prior to him even getting the board...
that's why his board won't boot, not because he's put tayeh with esr much lower than 0.10....
as he said
"I get readings all well below 0.1"

and according to willa's doc, that's ok
"For a motherboard we would want to use capacitors that are as far below 0.10 ohms that we can obtain. "
http://www.capacitorlab.com/esr-meter/index.htm


and i'm gonna trust willa and this man (who said he has esr lower than 0.10) and my experience where bulging caps with pretty damn high esr were still not making problems on mobos(offcourse that's doesn't mean they shouldn't be changed...as leaving them there is a risk..for semiconductors on the board) and not yours OR wizard's guessing...because it seems to me you didn't read half of this thread...
with esr readout there's no need to guess is tayeh in question good or bad cap...

[linuxguru]

Re: Intel D845GVSR Recap - No boot

He's investing quite a bit of effort in re-capping the mobo. Why use pulled Tayehs when provably more durable new caps are readily available?

This isn't a run-of-the-mill P3 mobo, it's an Intel P4 mobo - the ESR of the caps on Vcore is certainly critical. There's something like 50 Amps DC being drawn on that rail, with spikes of maybe 100 Amps or more on each FSB clock edge. If he has 10 caps of 0.1 ohm ESR in parallel on that rail, it's still 0.01 ohms, which gives a ripple of 1V at 100A on Vcore of 1.475 Volts - waaaay beyond the voltage specs on Vcore for the P4. OTOH, if it's 10 milliohm ESR, the ripple may be 0.1 Volts - within tolerance.

I'm fairly certain that pulled Tayehs won't cut it, but new MCZs will.

[i4004]

Re: Intel D845GVSR Recap - No boot

>Why use pulled Tayehs when provably more durable new caps are readily available?

let's put it this way: i didn't say he should not use best caps he can get, but i suggested he should check fets first. my prediction is that fets are blown(either them or some other seminconductors)

>If he has 10 caps of 0.1 ohm ESR in parallel on that rail

he said he has "well below 0.1", so why calculate with 0.1ohm?

>I'm fairly certain that pulled Tayehs won't cut it, but new MCZs will.

so you're certain about the cap's esr without measuring it yourself, and based on "well below 0.1" you say they're bad?
he
hehe...how coool is that? you can actually smell if the tayeh is good or bad even without knowing its esr precisely!
well done!

otoh, i'm still of opinion this mobo is not firing because of fets(or the other caps high esr...i think he didn't check all caps) and they should be checked first(both other caps, and fets)....given that he has 2 identical boards he should be able to figure it out...

i appreciate your notes on p4 ripple requirements...

[kc8adu]

Re: Intel D845GVSR Recap - No boot

considering the tayeh on the abit boards were about on par with fc new they are no way good enough for a p4 board even if they were fresh stock.
i would poke a scope on vcore to see the trash.used tayeh are most certainly pure junk.they were junk new.
mbz at a minimum or solid polys.
have one here with kzg which need replacement.has to be warm to post and even then it is not stable.
about .6v of trash on that one.
failure to post is not surprising on the o.p's board.

[i4004]

Re: Intel D845GVSR Recap - No boot

he has one board with some signs of life, and another completely dead...
i would be curious to test fets and caps of each board....prior to doing any soldering, that is...
yes, scoping the vcore too...