Hot location - recommendations?

[bw1]

I've got around 30 of these computers and have re-capped around 8 so far as I've needed them, and everything has been working great so far. I'm not doing a full re-cap, as there is definitely just a problem area with heat on the board, but I am replacing all 15 of the one particular brand/value of cap.

The board in the picture is done. I've marked the caps that have been replaced with blue dots. I know, again, not the greatest picture, but this is just to show locations of parts.

The three caps right behind the north bridge have been the problem area, and sometimes the one loaner right below them near the south bridge.

These computers have been running cool, to the touch and if you open one the air inside doesn't feel hot like some do, but before and after working on them the north bridge (heatsink'd) and south bridge (not heatsink'd) are too hot to touch. This makes the three caps behind the north bridge (getting a nice hot air draft from over the CPU and north bridge almost too hot to touch -- obviously the problem in the first place.

The originals were OST 6.3v 1000uf, and I've been replacing them with 10v 1000uf KZE's that match specs otherwise.

I can see this being a problem (again) down the road, but not sure whether I should keep going with these or find a different solution.

I installed the two caps by the PCI section laying flat to avoid clearance issues with expansion cards, as the replacements were taller than the originals.

[Uranium-235]

Re: Hot location - recommendations?

hmm, thermal adhesive a heatsink across the tops of those caps? (assuming they're in paralell)

[Colt45ws]

Re: Hot location - recommendations?

Heat sink the SB and put a 40mm on the northbridge.

[brethin]

Re: Hot location - recommendations?

Reverse the airflow in the case so you are not pushing hot CPU air across the board and caps. I have done this on several of my BTX setups that run really hot CPUs and it will help alot.

[bw1]

Re: Hot location - recommendations?

I guess my first questions are...

1.) How durable are the KZE's?
2.) Should I anticipate more problems in the short run? i.e. <2 years?
3.) I know many of the computers I work on have hot south bridge's... what I don't know is if it's a problem? This part seems pretty normal, and was the least of my worries. I worry more about the caps by the hot north bridge.

I've heard of people reversing the airflow on BTX systems before, and about a year ago read up on it a bit because there were some identical systems with opposite airflow, and I was trying to figure out which one was "right". I know there was controversy around the subject, and a lot of people taking both sides.

Thanks

[brethin]

Re: Hot location - recommendations?

If they are located in location that is hot (say 80+ F) then reversing the airflow is a big help because the air coming into the case and blown across the caps and north/south bridge will be room temp vrs the hotter air that has passed through the CPU heatsink which will be a great deal hotter than room air.

[370forlife]

Re: Hot location - recommendations?

You could always put poly's in there if you want to spend the extra dough.

[bw1]

Re: Hot location - recommendations?

You could always put poly's in there if you want to spend the extra dough.

I'm half tempted to just for those 3 or 4 caps and leave the rest the normal KZE's I've been using. The temp is definitely over 80*F on those three especially.

I know that switching to poly's isn't just a straightfoward swap... I've had assistance choosing poly's previously, but what are the guidelines there? My past experience is with v-core, not with "normal" locations.

If I were to switch these 3 or 4 to poly's, what would a good candidate be?

[PCBONEZ]

Re: Hot location - recommendations?

If they are directly on a PSU rail then dumping ESR on 2 or 3 isn't likely to hurt anything.
[The 1000uF scattered about mobos often are between either 3.3v or 5v and ground.]
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If they aren't then you need to trace the circuit to figure out what they do and what other components are in the circuit with them.
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[bw1]

Re: Hot location - recommendations?



Well the originals were 6.3v (used 10v replacements). So yep, they have to be 3.3v or 5v.

My skills being quite basic with tracing and identifying, I'm going to have to rely on some help from you to identify what their purpose is and what to replace with.

[PCBONEZ]

Re: Hot location - recommendations?

Use the ATX power connector and do resistance checks.
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If they are on a rail, one side with show a short to ground pins and the other side will show a sort to one of the power pins.
You will have to check all the power pins. If it was 12v that would include the 2x2 'P4' connector.
[Sometimes the different power pins are connected through the board and sometimes not.]
.