Mosfet Cooling

[Mir96TA]

I am trying to revive an Old IS7 system which going to run P4E 3.2.
It going to have a XP 70 CPU cooler.
I am concern about the MOSFET ........ I think they are getting tosted........
I was thinking about getting a stick on cooper passive cooler.
I am not sure how many there are, and which ones are excatly are the MOFSET.
I think it has 4 Mosfet which I have marked in the PIC.
Can any one confirm that for me and suggest a Mofset cooler

MACRO Shot

 

[(sic)Klown12]

Buy some RAM sinks that they sell for videocards and use some thermal tape. If your case has some airflow, the little sinks should be enough.

 

[Mir96TA]

BTW CPU cooler is XP-90 NOT XP 70

 

[mindwreck]

yeah some ram sink.. with the xp90 it should be fine since its a downward blowing design to blow air onto the mobo.

 

[Rubycon]

Those packages are cooled by sinking their tabs. You can add a sink to the package but this is not necessary IMO.

 

[Mir96TA]

Those packages are cooled by sinking their tabs. You can add a sink to the package but this is not necessary IMO.

Please explain, I am not sire I am following you :hmm:
Thanks Mir

 

[Mark R]

Please explain, I am not sire I am following you :hmm:
Thanks Mir

The heatsink attachment for MOSFETs is made of metal, and is soldered directly to the motherboard (which acts as a heatsink).

The ceramic/plastic package (the black part) does not have good thermal properties, and attaching a heatsink to this will not help cooling much.

 

[Rubycon]

The heatsink attachment for MOSFETs is made of metal, and is soldered directly to the motherboard (which acts as a heatsink).

The ceramic/plastic package (the black part) does not have good thermal properties, and attaching a heatsink to this will not help cooling much.

Yeah that covers that!

 

[Mir96TA]

cools
I am thinking about ordering Zalman RAM Sink 8 Pack W/ Thermal Tape
What you all think ?

 

[Rubycon]

That kit is fine however make sure none of the heatsinks touches the windings on those chokes nearby and be sure the tape securely holds the heatsinks to the MOSFET package! Also it will do very little to drop temperatures without sufficient airflow around them.

 

[Mir96TA]

That kit is fine however make sure none of the heatsinks touches the windings on those chokes nearby and be sure the tape securely holds the heatsinks to the MOSFET package! Also it will do very little to drop temperatures without sufficient airflow around them.

See this is what has happened
System has an Antec NEO HE 430Watts P/S
About a year ago system Bios started saying CPU Test Fail; but system was booting up and running fine.
Other day when I get to have the system, I have notice CPU cooler Bracket or retainer has broken anchor; which may not be holding a Cooler properly on the CPU; thus it may not be cooling P4 3.2 E effectively.
On my research what I have found CPU test it could be 12 volt rail failing or BAD CPU it self or could be VRM/ Mosfet failing.
When I got the system I updated the BIOS to latest, change the heat sink (For Testing purpose) and using different P/S ( I will try orig P/S to have reverse test and make sure it is P/S or what)
Going back to original issue; It want make sure those VRM/ Mosfet not getting cooked or putting extra load on the P/S or killing the P/S
Perhaps it can pull few more years; since it only use for watching Movies and E mail /Web ...... Owner is quiet happy with the performance

 

[Rubycon]

On an aging system you need to go over all the caps and make sure they are not showing signs of failure, i.e. bulges or weeping fluid (usually brown in color) from the top. The same goes with the PSU. Also verify voltages with a DMM.

Replace the CPU cooler and verify its effectiveness with a stress testing program such as Prime95, OCCT, or LinX.

 

[Mir96TA]

Yea I am going to do that.
CAPS looks good to me.
I have to get a 478 retainer bracket.
I am going to use a spair P/S which is known good

 

[aigomorla]

http://www.jab-tech.com/Enzontech-Mosfet-Heatsink-MOS-C1-pr-4112.html

Pictures in this section = 1000000000000000000000000000000000000000000000 words.. :twisted:

need i say more?

The heatsink attachment for MOSFETs is made of metal, and is soldered directly to the motherboard (which acts as a heatsink).

The ceramic/plastic package (the black part) does not have good thermal properties, and attaching a heatsink to this will not help cooling much.

I had a long and simular topic about this guy:

This is without the sink:

The issue is the plastic does get hot.
The sink does keep plastic cool.

Even tho heat transfer is small, there is still transfer, and the sink keeps the overall component cooler.

So if you ask me... every last bit counts if your going after durability.
Things last longer as they run cooler.

 

[Rubycon]

http://www.jab-tech.com/Enzontech-Mosfet-Heatsink-MOS-C1-pr-4112.html

Pictures in this section = 1000000000000000000000000000000000000000000000 words.. :twisted:


need i say more?



I had a long and simular topic about this guy:


This is without the sink:


The issue is the plastic does get hot.
The sink does keep plastic cool.

Even tho heat transfer is small, there is still transfer, and the sink keeps the overall component cooler.

So if you ask me... every last bit counts if your going after durability.
Things last longer as they run cooler.

Apple meet orange.
The parts in the OP have much lower power density then yours. Modern day board power supplies won't even survive without a heat sink!
While it may be true it helps to cool as long as the part remains within the SOA at all times there is no issue with reliability. Inadequate design and/or pushing margins way beyond design specification are the leading cause of failures in this area.

 

[aigomorla]

Apple meet orange.

can i get a peach instead? :biggrin:

but regardless keeping it cooler extends the life of any product.

and worst comes to worst, it prevents dust from collection over the mosfet.
Instead it collects inside the pins. :biggrin:

 

[God Mode]

Best way to tell would be checking with an ir thermometer. Personally, I wouldn't obsess over it. I've had the cheapest boards overclocked in a hot case with dismal ventilation and none ever died during its use.