Question Thermal paste at the bottom center of the CPU

[shoohs]

Please help. I recently bought a Intel i7 4790 non-k cpu but the cpu has thermal paste at the bottom center of the cpu itself not on the pads but on the center part of cpu. Right at the bottom center where those transistors or idk what are those on the cpu. Does my Cpu will still work or not? How do I remove this paste?

P.S. the thermal paste isn't quite as much as big but a fine dot.

 

[Darkbreeze]

Yes. That is the standard method, for as far back as I can remember. Probably, since changing paste became a thing at all.

 

[shoohs]

So, using lint free cloth and a isopropyl alcohol that's 70% solution should work fine in cleaning the bottom of my CPU? thanks a lot btw

 

[Darkbreeze]

You don't want 70%. That's too weak. You want the 91% isopropyl alcohol.

There is too much water content in the 70% variety and it takes too long to dry. I mean, if you needed to do this on a deserted island and all you had was a bottle of 70%, then I guess you COULD get by with it, but it's definitely not the recommended prescription.

 

[grimfox]

WOW.

I work at a electronics manufacturer as an engineer. We make electronics all the time. It's my job. We frequently have to perform rework/repairs that requires using various cleaning methods. The primary means of spot cleaning a residue is... alcohol and a Q-tip. We use 91%, because it's hardly more expensive when you are buying cases of it, as compared to 70%. That said 70% works just fine for 90% of applications.

Hell, much of our product is cleaned using water. Heavily filtered DI water because we are a business that can afford to do that but water all the same. If cold alcohol and a Qtip isn't working, Hot water and a toothbrush would be slightly more aggressive. Flush the processor with alcohol afterwords to ensure the water isn't going to leave behind any residue. In most cases that residue wont cause a problem. If you do wash with water allow the CPU to dry for an extended period (or bake it in an oven set to less than 100C (212F) for a couple hours. Don't exceed 100c as that will cause the water to boil and could cause damage) this will allow any water that was absorbed into the device to evaporate out slowly.

Sometimes Qtips will leave fibers but, fun fact, cotton is non-conductive. Therefore it's not an issue if a few strands are left behind. I've yet to see a product returned as a result of a cotton fiber causing a problem. A soft toothbrush isn't even a strict requirement. some of the toothbrushes we have on site and use for cleaning are pretty rough looking, they are stiff and pretty aggressive. We occasionally have to use a fiber brush. Which is a brush with glass fiber bristles for baked on residue or stray solder balls.

Electronics are far more robust than most people give them credit for.

 

[drea.drechsler]

....
Hell, much of our product is cleaned using water. Heavily filtered DI water because we are a business that can afford to do that but water all the same
...
Sometimes Qtips will leave fibers but, fun fact, cotton is non-conductive.
...

Be careful with DI water washes. Not that it's immediately harmful if fairly quickly dried off, but left in a bath of it can lead to corrosion as it aggressively tries to 'steal' ions from it's environment. But luckily, nobody in these forums should have to worry about that.

Lost in the craziness, but the problem with the Q-tip fibers is they can become entrapped between the heat spreader and cooler mounting surface. A tiny thing and maybe no big deal, but nevertheless contributing to less than ideal contact patch. This becomes especially important for one who laps said surfaces to a mirror finish. And lastly, when striving for perfection i guess it's something you can do when you otherwise feel nothing else will help.

 

[Darkbreeze]

There are plenty of "standard practices" used by those in various industries that are MUCH less than desirable. People who "work" in a given industry become inured to the idea that a thing is not the right way to do something because they've been doing it that way for a long time. As another moderator here likes to say quite often, people walk out into traffic all the time, it doesn't mean it's a good idea or that you should do it. Just because you haven't been run down yet, doesn't mean it won't happen eventually.

 

[drea.drechsler]

There are plenty of "standard practices" used by those in various industries that are MUCH less than desirable....

I don't know exactly what you're getting on about, but I assume this is a response to @grimfox 's post. Also being an engineer who worked in ultra-hi-reliability aerospace electronics manufacturing, which is by it's nature one-off and very labor intensive for it, I can attest to his methods as not only 'standard' but 'best in industry'. Simple solutions to complex problems are usually preferred and environmentally safe water wash fluxes, lead free solders and a desire not to poison operators or environment with hazardous solvents (MEC, MEK, CFC's, etc.) have lead to adoption of those methods as pretty much the best.

 

[grimfox]

Be careful with DI water washes. Not that it's immediately harmful if fairly quickly dried off, but left in a bath of it can lead to corrosion as it aggressively tries to 'steal' ions from it's environment. But luckily, nobody in these forums should have to worry about that.

Lost in the craziness, but the problem with the Q-tip fibers is they can become entrapped between the heat spreader and cooler mounting surface. A tiny thing and maybe no big deal, but nevertheless contributing to less than ideal contact patch. This becomes especially important for one who laps said surfaces to a mirror finish. And lastly, when striving for perfection i guess it's something you can do when you otherwise feel nothing else will help.

I think I outlined in my post how we use DI water for cleaning fairly well. And my description specifically included a flush and appropriate drying. We actually have a machine wash, which is basically a dishwasher for circuit boards to handle the washing and drying.

All in fun, I'd like to call you out on the cotton fiber in your thermal paste argument. In theory you are right but you're going to have a hard time proving even a 1degree change in temps as a result of a stray cotton fiber. If you can prove even a small performance change IE I couldn't get another 10Mhz out of this processor because of that cotton fiber, I'll eat the rest of this box of Samoas. Hahaha.

There are plenty of "standard practices" used by those in various industries that are MUCH less than desirable. People who "work" in a given industry become inured to the idea that a thing is not the right way to do something because they've been doing it that way for a long time. As another moderator here likes to say quite often, people walk out into traffic all the time, it doesn't mean it's a good idea or that you should do it. Just because you haven't been run down yet, doesn't mean it won't happen eventually.

People might walk out into traffic. Engineers build a crosswalk/bridge/tunnel to cross the street safely.

 

[drea.drechsler]

I think I outlined in my post how we use DI water for cleaning fairly well. And my description specifically included a flush and appropriate drying. We actually have a machine wash, which is basically a dishwasher for circuit boards to handle the washing and drying.
....

We also had a water wash for boards coming out of mass soldering processes...and in-house modified Kitchenaid dishwashers with racks that held PWA fixtures for demand cleaning in specialized workcenters. I don't think anyone can really appreciate exactly what's meant by plain-old water being a 'universal solvent' until having had a chance to play around with 20 Meg-Ohm DI water. Now, I seriously respect the stuff.

And as far as the thing about cotton fibers...as I noted, people lap the surfaces of heatsink and cooler. After, even seeing only 1 degree improvement they declare how grand it is. If they want to also obsess over a tiny fiber of cotton, that's OK by me. I personally don't care; I use a paper towel to wipe off the paste, don't worry about the mess around the edges of the heat spreader, whatever gets onto the socket STAYS THERE and use the pea-size dot in the center method for spreading.

 

[Darkbreeze]

Engineers don't walk anywhere. They are too occupied with figuring out ways to not have to walk, to be bothered with the whole "walking" thing.

And I was not really specifically addressing or disagreeing with anybody, per se. Just saying that there are a lot of people in various fields that use specific routines as acceptable, that really aren't. I wasn't saying that what you do, in that particular field, wasn't an acceptable practice, however, for THIS field, regarding the replacement of TIM on a heat spreader or the bottom of a heatsink, it is a generally held and accepted believe that using lint free cloths or some form of lint free paper product, should be employed for the specific reason of avoiding leaving ANY fibers on the surfaces because exactly as was mentioned and regardless of the fact that it might only be hundredths or thousandths of an inch of interference, it does in fact leave something to stop what you hope to be a purely flat on flat surface (Which it rarely is, but that's a different discussion) from being able to actually mate as closely as possible.

I really doubt that anybody is going to argue that when it comes to mating a heatsink to any surface, you don't want anything EXCEPT for the thermal interface material to be in between the two surfaces. That's not rocket science, it's just common sense.

 

[grimfox]

@drea.drechsler I think @Darkbreeze is a scientist, while we are engineers. And I think he implied that engineers never get anything done.

 

[Darkbreeze]

Nah, engineers get plenty done. It's just that they get a bonus if they make life hard on me, at the mechanic/technician end of things.

 

[shoohs]

At first, the processor was kinda tweaked out, didn't functional out well as I didn't remove the thermal paste, keeps the PC restarting.

 

[shoohs]

At first, the processor was kinda tweaked out, didn't functional out well as I didn't remove the thermal paste, keeps the PC restarting.

As I apply the isopropyl alcohol, it did turn out well to be a great option. No more restarts and the PC keeps running these days. Thanks a lot who helped!

 

[Darkbreeze]

You DID put fresh thermal paste on there AFTER you cleaned the old thermal past off using the isopropyl alcohol, right?

And you DID clean the old thermal paste off the surfaces of both the CPU and the bottom of the CPU cooler heatsink, yes?