[Elecraft] Noisy KPA100 Fan

[Mario Lorenz]

Am 07. Nov 2002, um 16:33:56 schrieb Phil Wheeler:

> I don't recall this sound being there early on, but maybe I'm wrong.  I 
> do know that I have not put enough hours on the PA to wear anything out.

Well, you seem to overestimate the quality of mechanical parts built
in these times.

I have seen CPU fans start making noises within 2 weeks. I didn't
dissassemble the KPA fan (mine is OK so far) to see what type
of bearing it has, but I really doubt its a ball bearing. While
ball-bearing fans are generally quieter, they are very fragile. Drop 
such a fan to the floor, it will look fine. But a couple million
revolutions later, the damage will show.

The plastic/sinter bearings are particularly vulnerable to dust getting
into the bearings, where friction has the obvious effects.  

Once the fan starts to sound scratchy, it usually cannot be helped. It
might be good for quite some time tho. Some oil, injected right into
he bearing using an injection needle sometimes helps, but not for long.

Once you replace it, you might want to protect it from dust - 
something like very fine grill cloth perhaps.

Mario

-- 
Mario Lorenz                            Internet:    <ml@vdazone.org>
                                        Ham Radio:   DL5MLO@OK0PKL.#BOH.CZE.EU
Trust the computer industry to shorten "Year 2000" to Y2K.  It was this kind
of thinking that caused the problem in the first place.