is it bad to have the heatsink puching against caps?

[shovenose]

i put the board from a 1u server (dual p3) - into an atx case. and i also got bigger heatsinks (the original super tiny ones reached up to 97c sometimes idle not kidding
now my temps are better but i had to push the heatsink really hard against the caps was worried id tear them out. it seems ok though but will this be bad in the long run?

[seanc]

Re: is it bad to have the heatsink puching against caps?

Pushing against the top of the caps, or pushing them out sideways?

Both are bad.

The former could create a short, the latter could damage the capacitor, capacitor lead or bung seal.

[Rob Northen]

Re: is it bad to have the heatsink puching against caps?

Heatsinks tend to get.. warm and caps up close ?
VERY BAD!

[seanc]

Re: is it bad to have the heatsink puching against caps?

I also forgot the other obvious point that Rob mentioned :P

[berniedd]

Re: is it bad to have the heatsink puching against caps?

Definitely not good. If you want cooler processors, you could grind down the offending appendages on your new heatsinks to avoid hitting the caps. Better yet, upgrade the fans to faster/better units instead of the heatsinks.

[stevo1210]

Re: is it bad to have the heatsink puching against caps?

yes, you might actually end up frying those caps!

[shovenose]

Re: is it bad to have the heatsink puching against caps?

hmmm...ok. this was supposed to be server fr my house eventually so it must be reliable.
ok so im seeing this isnt good.
but to whoever asked, pushing the sideways.
would i have been safe to say if it still works a weeks later it'll be fine. and btw theyre rubycons so theyre good if it were an ost or something i wouldnt even have done it

[dood]

Re: is it bad to have the heatsink puching against caps?

I just replaced some Rubycons that had been cooked by an excessively hot SFF PC. Even Rubycons will cook if exposed to higher temps. Pushing the caps sideways pulls the leads through the bung on the one side, which can lead to leakage of the electrolyte.

It's one thing to mount caps sideways so that they clear (by soldering one leg slightly out of the board), but it's a whole 'nother thing to pull one sideways that's already hard soldered to the board.

I would shoot for taller, not wider, heatsinks.

[shovenose]

Re: is it bad to have the heatsink puching against caps?

i didnt realize the caps were super close to the socket when i ordered the sinks on ebay

[dood]

Re: is it bad to have the heatsink puching against caps?

Well, lesson learned. Always keep an eye on how close things are to the socket before you order oversized HSF's !

[PCBONEZ]

Re: is it bad to have the heatsink puching against caps?

An option is to cut or notch the heat-sinks for cap clearance.
Not hard to do with aluminum.
.

[stj]

Re: is it bad to have the heatsink puching against caps?

foto's ?

[StevieC]

Re: is it bad to have the heatsink puching against caps?

So we know that it's bad if the heat-sink is PUSHING on the cap. What about if it's just touching or merely brushing the cap with virtually no contact at all?

[stj]

Re: is it bad to have the heatsink puching against caps?

some airspace would be preferable.
or chill the fuck out of the heatsinks.

what i did once on a dual p3 slot-type, was to remove the small fans from each sink and fit a 120mm blowing DOWN over both sinks at the same time.
that workd well.

[PCBONEZ]

Re: is it bad to have the heatsink puching against caps?

Yes you want some airspace there.
Heating up caps => bad.

According to most cap manufacturers for each 10 degrees C you raise cap temp the cap's Life-Span is reduced by 50%.
- It's logarithmic.
- It stacks up fast.
Assuming a cap is good for 12 years at 50C....
.... it's good for 6 years at 60C, 3 years at 70C and 1.5 years at 80C.

And before it goes there again...
The 'Lifetime' given in datasheets doesn't have much to do with Life-Span.
The 'Lifetime' given is actually 'Endurance Lifetime' which is how many hours you can abuse the snot out of a cap WITHOUT causing permanent damage.
There are equations to estimate Life-Span from the advertised 'Endurance Lifetime' but they are only good to +/-40% accuracy.
If the equations determine a Life-Span of 8 years then with +/-40% what it really means is "anywhere from 4.8 years to 11.2 years."
So: from a practical standpoint those equations don't give useful numbers and are a waste of your time.
.