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Author Topic: Common PC fan repair...  (Read 9069 times)

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Offline hacklordsniper

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Common PC fan repair...
« on: August 05, 2011, 04:46:20 AM »
While i was washing and drying various consumer electronics boards scavenged today for parts transplatation to my bin tomorrow i had an idea... My projects always mostly use a fan but i always bought a new one since they are cheap.

But why not recycle them? There is no life for them on the dumpster.

So first take these dirty fans and put them in your bathtub. Give them a nice hot shower and wash them with dish washer detergent.

Warning - remeber to lock the door of bathroom so your wife does not see that you are putting dirty fans in bathtub she cleaned few minuttes ago

After few washings and they are clean dry them with compressed air.

First patient draw more than 1 A, spins very slow...

Take your Atten 858 soldering iron and heat the label to remove it carefully. You will need it later. Remove the rubber seal, then use tweezers to remove white lock and a small rubber seal again. At this moment the fan will fall apart and you will see why it does not work. Clean all parts, apply ball bearing grease (not regular one, but the one designed for small bearings) to axle and top and bottom of fan. Reassemble and test

Patient lives, works nicely and even the input current is lower than specs. After about 10 minute "burn-in" the current fell off to about 190 mA (as the grease spreaded where needed) and fan is absolutely silent and working perfectly.

Maybe a time consuming work but surely recycling is better  :)

Oh, the joy of sending various electronics to silicon heaven
 

Offline KuchateK

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Re: Common PC fan repair...
« Reply #1 on: August 05, 2011, 05:14:43 AM »
I did this as well. I was waiting for replacement non-standard fan and I decided to wash existing one.

In my case I disassembled the fan first. Then I washed blades and cleaned the case with compressed air and damp cloth, which saved bearings and electronics from water.

Definitely worth the time. It takes 10 minutes and you can save a lot on better/bigger fans.
« Last Edit: August 05, 2011, 06:11:54 AM by KuchateK »
 

Online Fraser

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Re: Common PC fan repair...
« Reply #2 on: August 05, 2011, 06:40:59 AM »
This may be a method to get some additional hours out of a knackered fan but a word or caution if it's continued operation is important.

Cheap brushless fans use Oilite bearings and expensive ones tend to use high quality ball races. Neither appreciates a bath in hot detergent as it removes any remaining lubrication as well as the dirt  :o

Once a fan gets noisy or stiff (causing excess current draw) you have to consider the condition of the bearing and not just cover up the issue with a clean and lube to the bearing surfaces. An oilite bearing is impregnated with oil that is held in it's porous structure. This is done at the time of bearing manufacture and is not just externally lubricated with some bearing oil. The oil gradually evaporates or thickens with time so the bearing effectively dries out. Oilite bearings can only be properly rejuvenated by a long soak in a hot oil bath, whilst a contaminated ball race requires cleaning, degreasing and repacking with light grease. I have had some success with leaving oilite bearings to soak in room temperature sewing machine oil that is very thin. The bearing appears to absorb some of the oil into its bearing surface but this is not as effective as boiling the bearing in oil.

If a fan has has become noisy and contains an oilite bearing it is worth checking for play and wear on the bearing surfaces as once the oilite bearing dries out it will wear very quickly if the fan continues to be used.

Oil and grease lubrication of a knackered fan DOES fix it for a time but sadly it will return to it's bad habits sooner rather than later. Google 'oilite bearings' to find out more about them.

I don't want to take anything away from your nice fan refurbishment description but you do need to understand it's limitations.
« Last Edit: August 05, 2011, 06:46:13 AM by Aurora »
 

Online Hero999

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Re: Common PC fan repair...
« Reply #3 on: August 05, 2011, 06:59:11 AM »
I'm sure you know this. You shouldn't spin the fan roo fast with compressed air of a vacuum cleaner because the voltage generated in the motor windings will fry the inverter.
 

Offline Kiriakos-GR

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Re: Common PC fan repair...
« Reply #4 on: August 05, 2011, 07:39:50 AM »
I had save this little one from the trash box.  :)
It was had just a bad solder in the one of the four windings.

Large and silent,  I keep it around for special tasks.

 
 

Offline hacklordsniper

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Re: Common PC fan repair...
« Reply #5 on: August 05, 2011, 03:56:54 PM »
Aurora:

I understand your point and thank you for writing it here. The fans that i i opened are mostly from PC power supplies and they were not at end of their life cycle just clogged with dirt which stopped their rotation and blew the supply. Also all of there were low quality fans without actual ball bearing but with bronze bearing for which i suspect is not even oilite.

I have left all of the fans running over night and they all work perfectly and quite without any play on the axle. Since they will not be used in "mission critical" environment (for such tasks i buy new fans with fluid bearing) but for testing and various projects.

Also since the fan have a rubber seal in bottom and on top also none of the water came in the bearing.

Generally in conclusion i just regret to throw them in the trash bin since they could still be useful somewhere but i know im just collecting junk i will rarely use  :)

You are not taking anything away from this post  as a purpose of community i know something you don't know, you know something i don't know and together we know more.

Oh, the joy of sending various electronics to silicon heaven
 

Uncle Vernon

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Re: Common PC fan repair...
« Reply #6 on: August 05, 2011, 04:08:03 PM »
Cleaning PC fans! Every smoker should have to wade through the muck in a smokers PC fan. If that doesn't put you off (or make you violently ill), then nothing will.
 

Offline hacklordsniper

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Re: Common PC fan repair...
« Reply #7 on: August 05, 2011, 04:16:12 PM »
Cleaning PC fans! Every smoker should have to wade through the muck in a smokers PC fan. If that doesn't put you off (or make you violently ill), then nothing will.

I had to throw out this power supply http://www.eevblog.com/forum/index.php?topic=4250.0 because who ever was using it puffed smoke directly in it. The outsides were full of tar and no mater how i washed it it made you ill if you were close to it
Oh, the joy of sending various electronics to silicon heaven
 

Re: Common PC fan repair...
« Reply #8 on: August 05, 2011, 05:00:06 PM »
Every smoker should have to wade through the muck in a smokers PC fan. If that doesn't put you off (or make you violently ill), then nothing will.

My experience with smokers is they rather inhale the odor to get an extra kick than to be put off. One key issue with smokers is they have no sense for smoke dirt and they almost don't smell anything any more. E.g. they don't smell that they stink and their clothes stink.
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