[CentOS] died again

Warren Young warren at etr-usa.com
Sat Dec 7 00:39:29 UTC 2013


On 12/6/2013 16:34, Michael Hennebry wrote:
> There is a place for a front fan, but no fan there.

It's common for cheap PC cases to have places for fans that the final PC 
manufacturer chooses not to populate.

If you decide to put a fan there, be sure to orient it so it blows "in 
line" with the case exhaust fans.  You don't want two fans blowing 
opposite directions on opposite sides of the case.  The plastic fan 
shroud usually has a molded-in arrow showing the airflow direction.

> The plastic front of the case would have pretty much blocked it.

Maybe not.  Some PC case bezels have vents at the bottom edge.  A common 
pattern is for the front PC fan to suck air in, and for the rear PC fans 
to blow air out.  Since they're usually at opposite corners of the case, 
this forces air to flow through the entire case.

> The power supply is a sealed unit,

I think you'll find that once you unscrew it from the case, you'll 
expose another set of screws that will let you remove the power supply's 
lid.  The odd hole in the back of the case is designed to block access 
to these screws, on purpose.

Don't touch anything in there unless you know your microfarads from your 
microhenries.  Just take pics.

> I'm going to get my camera and take some
> pictures.

Please do.  We may well see something you didn't.

Some advice, based on prior experience receiving uselessly bad pictures 
in the DIY electronics slice of my life:

1a. Turn on lots of lights and shine them into the case.  Experiment 
with forced camera flash.  Electronics enclosures (including PC cases) 
are often dark places, which means not enough photons for your camera to 
take a fast, sharp picture.  If you can't get enough artificial light 
into the case, take it outside and shoot into the case with the sun over 
your shoulder.

1b. Bounce or diffuse as much of the light as possible.  Lots of direct 
light is good, but if it creates blown-out flare spots or inky shadows 
that obscure detail, it's still no good.  There are many ways to make 
cheap diffusers and bounce cards: old thin sheets, tin foil, poster 
board...  Tenting a sheet over your head and the case can give a better 
result than a bright direct light.  If your camera's flash is 
articulated, bounce it into the scene rather than shoot directly in.

2. Use your camera's macro function, if it has one.  10 separate 
pictures of 10 details is better than one overall picture where you 
can't even tell how many pins are on a given chip.

3. Use a tripod, if you have one.  If you don't, brace the camera 
against something: a nearby wall, the PC case, a sandbag...  A camera on 
a tripod set for a 30 second exposure can compensate for a *lot* of 
problems in area #1.



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