I've got a small 12V DC .9 Watt 'muffin' fan (1.75"x1.75"x3/8").
It was the cooler for a video card's processor chip and was
frozen up.

I put a drop of oil into its sleeve bearing and it now runs
reliably - almost. It will start every time as long as it is
not oriented with the open 'face' down. (The open face is the
side in which you can see the bearing). If the open bearing is
down, it sometimes starts and sometimes needs a slight nudge to
get it going.

What's going on? How come? TIA

"Bennett Price" ""bjpriceNOSPAM\"@NOSPAMcal berkeley.edu" wrote in message
...
I've got a small 12V DC .9 Watt 'muffin' fan (1.75"x1.75"x3/8").
It was the cooler for a video card's processor chip and was
frozen up.

I put a drop of oil into its sleeve bearing and it now runs
reliably - almost. It will start every time as long as it is
not oriented with the open 'face' down. (The open face is the
side in which you can see the bearing). If the open bearing is
down, it sometimes starts and sometimes needs a slight nudge to
get it going.

What's going on? How come? TIA


Presumably because the bearings are worn out. Get another one.



Gareth.

"Bennett Price" ""bjpriceNOSPAM\"@NOSPAMcal berkeley.edu" wrote in message
...
I've got a small 12V DC .9 Watt 'muffin' fan (1.75"x1.75"x3/8").
It was the cooler for a video card's processor chip and was
frozen up.

I put a drop of oil into its sleeve bearing and it now runs
reliably - almost. It will start every time as long as it is
not oriented with the open 'face' down. (The open face is the
side in which you can see the bearing). If the open bearing is
down, it sometimes starts and sometimes needs a slight nudge to
get it going.

What's going on? How come? TIA


The bearing may be a bit loose. I've had some success disassembling these
fans, cleaning out the dried up muck, and putting on fresh oil then
reassemble. It's better to replace it, but if you need to use the computer
and don't have one on hand, it works in a pinch.

Bennett Price wrote:

I've got a small 12V DC .9 Watt 'muffin' fan (1.75"x1.75"x3/8").
It was the cooler for a video card's processor chip and was
frozen up.

I put a drop of oil into its sleeve bearing and it now runs
reliably - almost. It will start every time as long as it is
not oriented with the open 'face' down. (The open face is the
side in which you can see the bearing). If the open bearing is
down, it sometimes starts and sometimes needs a slight nudge to
get it going.

What's going on? How come? TIA

What voltage are you applying to it?

Bennett Price wrote:
I've got a small 12V DC .9 Watt 'muffin' fan (1.75"x1.75"x3/8").
It was the cooler for a video card's processor chip and was
frozen up.

I put a drop of oil into its sleeve bearing and it now runs
reliably - almost. It will start every time as long as it is
not oriented with the open 'face' down. (The open face is the
side in which you can see the bearing). If the open bearing is
down, it sometimes starts and sometimes needs a slight nudge to
get it going.

What's going on? How come? TIA

You oiled it, but you didn't get the gunk off the shaft. When the fan
is oriented face down there is enough endplay in the shaft for the bit
of gunk left on it to bind in the bearing. When it's face-up, that part
of the shaft is likely outside of the bushing.

When doing these, I usually operate them briefly with some kind of
solvent, until they run freely again. Then I flush the bearing with
that solvent--blow as much of it out as possible--THEN relube with 3 in
1 type oil.

Sometimes I also pack the open space with a bit of cheap grease before
resealing...figuring that if the bearing starts to get hot because of
binding, some of that grease will liquefy and and replenish the bearing.
I don't know if that's valid, but I usually get good life out of the
refurb.

OTOH, fans are cheap and readily available...much cheaper than the stuff
they protect.

jak

Anywhere from 9 to 15 volts. At 9 it will run in every other position,
at 15 vdc in the face down position it will still need a nudge.


UCLAN wrote:
Bennett Price wrote:

I've got a small 12V DC .9 Watt 'muffin' fan (1.75"x1.75"x3/8").
It was the cooler for a video card's processor chip and was
frozen up.

I put a drop of oil into its sleeve bearing and it now runs
reliably - almost. It will start every time as long as it is
not oriented with the open 'face' down. (The open face is the
side in which you can see the bearing). If the open bearing is
down, it sometimes starts and sometimes needs a slight nudge to
get it going.

What's going on? How come? TIA

What voltage are you applying to it?

Bennett wrote:

Anywhere from 9 to 15 volts. At 9 it will run in every other position,
at 15 vdc in the face down position it will still need a nudge.


UCLAN wrote:

Bennett Price wrote:

I've got a small 12V DC .9 Watt 'muffin' fan (1.75"x1.75"x3/8").
It was the cooler for a video card's processor chip and was
frozen up.

I put a drop of oil into its sleeve bearing and it now runs
reliably - almost. It will start every time as long as it is
not oriented with the open 'face' down. (The open face is the
side in which you can see the bearing). If the open bearing is
down, it sometimes starts and sometimes needs a slight nudge to
get it going.

What's going on? How come? TIA


What voltage are you applying to it?
chances are you have a pressed in race for the bearing.
you maybe able to tap it in deeper if you can get to it.



http://webpages.charter.net/jamie_5"

"Gareth Magennis" writes:

"Bennett Price" ""bjpriceNOSPAM\"@NOSPAMcal berkeley.edu" wrote in message
...
I've got a small 12V DC .9 Watt 'muffin' fan (1.75"x1.75"x3/8").
It was the cooler for a video card's processor chip and was
frozen up.

I put a drop of oil into its sleeve bearing and it now runs
reliably - almost. It will start every time as long as it is
not oriented with the open 'face' down. (The open face is the
side in which you can see the bearing). If the open bearing is
down, it sometimes starts and sometimes needs a slight nudge to
get it going.

What's going on? How come? TIA

Presumably because the bearings are worn out. Get another one.

I've disassembled these, cleaned, and relubed with decent success.

But a new fan is not expensive.

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"Sam Goldwasser" wrote in message
...
"Gareth Magennis" writes:

"Bennett Price" ""bjpriceNOSPAM\"@NOSPAMcal berkeley.edu" wrote in
message
...
I've got a small 12V DC .9 Watt 'muffin' fan (1.75"x1.75"x3/8").
It was the cooler for a video card's processor chip and was
frozen up.

I put a drop of oil into its sleeve bearing and it now runs
reliably - almost. It will start every time as long as it is
not oriented with the open 'face' down. (The open face is the
side in which you can see the bearing). If the open bearing is
down, it sometimes starts and sometimes needs a slight nudge to
get it going.

What's going on? How come? TIA

Presumably because the bearings are worn out. Get another one.

I've disassembled these, cleaned, and relubed with decent success.

But a new fan is not expensive.



Yes, not nearly as expensive as the possible damage caused by a stalled worn
out fan that soemone tried to bodge back to working condition instead of
replacing it. I'm thinking Power Amps, computer chips, or any gear that
someone has paid you to fix properly.


Gareth.


Gareth.

"Gareth Magennis" wrote in message
...

"Sam Goldwasser" wrote in message
...
"Gareth Magennis" writes:

"Bennett Price" ""bjpriceNOSPAM\"@NOSPAMcal berkeley.edu" wrote in
message
...
I've got a small 12V DC .9 Watt 'muffin' fan (1.75"x1.75"x3/8").
It was the cooler for a video card's processor chip and was
frozen up.

I put a drop of oil into its sleeve bearing and it now runs
reliably - almost. It will start every time as long as it is
not oriented with the open 'face' down. (The open face is the
side in which you can see the bearing). If the open bearing is
down, it sometimes starts and sometimes needs a slight nudge to
get it going.

What's going on? How come? TIA

Presumably because the bearings are worn out. Get another one.

I've disassembled these, cleaned, and relubed with decent success.

But a new fan is not expensive.



Yes, not nearly as expensive as the possible damage caused by a stalled
worn out fan that soemone tried to bodge back to working condition instead
of replacing it. I'm thinking Power Amps, computer chips, or any gear
that someone has paid you to fix properly.


Gareth.




Doesn't sound like anyone has paid him to fix it, the assumption is that
it's his own stuff that he's fixing himself. I've been known to repair these
little fans so I can keep using my PC until I can find a suitable
replacement. Some graphics chipsets use oddball custom heatsink/fan
assemblies that are difficult to find replacements for.

On Sat, 19 Apr 2008 18:16:17 GMT, Bennett Price
""bjpriceNOSPAM\"@NOSPAMcal berkeley.edu" wrote:

I've got a small 12V DC .9 Watt 'muffin' fan (1.75"x1.75"x3/8").
It was the cooler for a video card's processor chip and was
frozen up.

I put a drop of oil into its sleeve bearing and it now runs
reliably - almost. It will start every time as long as it is
not oriented with the open 'face' down. (The open face is the
side in which you can see the bearing). If the open bearing is
down, it sometimes starts and sometimes needs a slight nudge to
get it going.

What's going on? How come? TIA

Realizing that this comes under the heading of "beating a dead horse .
.. ."

Only one continuous long bearing supports the shaft? Some have two
sleeves and you can only see one if you pull the label off - you also
have to pull the shaft completely out.

I've had the same experiences with sintered bearings - the sleeve is
porous and a drop of lube doesn't really do much. The thing worked
for years and has a particles of grunge and a residue of dried oil
filling the lubricating channels in the metal.

If the sleeves can be removed, a cleaning with an ultrasonic cleaner
and some thin petroleum solvent (mindful of the hazards there) will do
wonders if the surface is still round (and if you don't see scoring it
probably is) - then heat the sleeve to 250 F, let it soak at that temp
for an hour, and drop it into lubricating oil to cool to room temp
before replacing.
--


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Thanks to all who have responded. I immediately replaced the fan with
another one - had to devise a way to mount it on the video card heat
sink which wasn't straightforward. I was just curious about why the fan
was so position sensitive.

Bennett Price wrote:
I've got a small 12V DC .9 Watt 'muffin' fan (1.75"x1.75"x3/8").
It was the cooler for a video card's processor chip and was
frozen up.

I put a drop of oil into its sleeve bearing and it now runs
reliably - almost. It will start every time as long as it is
not oriented with the open 'face' down. (The open face is the
side in which you can see the bearing). If the open bearing is
down, it sometimes starts and sometimes needs a slight nudge to
get it going.

What's going on? How come? TIA

In article , Bennett Price ""bjpriceNOSPAM\"@NOSPAMcal berkeley.edu" wrote:
Thanks to all who have responded. I immediately replaced the fan with
another one - had to devise a way to mount it on the video card heat
sink which wasn't straightforward. I was just curious about why the fan
was so position sensitive.

Bennett Price wrote:
I've got a small 12V DC .9 Watt 'muffin' fan (1.75"x1.75"x3/8").
It was the cooler for a video card's processor chip and was
frozen up.

I put a drop of oil into its sleeve bearing and it now runs
reliably - almost. It will start every time as long as it is
not oriented with the open 'face' down. (The open face is the
side in which you can see the bearing). If the open bearing is
down, it sometimes starts and sometimes needs a slight nudge to
get it going.

What's going on? How come? TIA

Sleeves slide around, ball bearing fans seem spring loaded, so position
is less important.

greg