9 Oct
2011
9 Oct
'11
12:52 p.m.
On 8 Oct 2011 at 18:33, Jules Richardson wrote:
All my HP9800s and most of my minicomputers (all early 1970s machines)
are still running on their original fans. I do stip them and lubricate
them when I first clean up the machine but that's all.
If you have fans, they eventually break, and to
do things 'properly'
they also have to be monitored and the OS/firmware written to safely
handle a failure condition.
That's mostly because almost nobody makes good fans any more. I have
some metal-frame Rotron "Sprite" fans that have passed their 40th year in operation. I also don't hear about too
many of the original
AC powered fans in old IBM 5150s packing up.
I did have the rpelace the DC fan in a 5170 PSU, though :-(
Essentially, the problem is that purchasing managers don't want to
pay for good fans. Anything than can turn in 18 months of operation
without locking up must be good enough.
On one of the other electronics-related forums some time ago, I
mentioned using an AC-powered fan as a reasonable alternative to
cheap plastic Chinese DC fans. One of the forum members took
exception to my suggestion and said an AC (shaded pole) fan would
kick up enough RF energy to destroy all the ICs in the box. When I
Can you please explain hoiw a shaded pole motor generates RF energy? If
anything, a DC fan, with electornic commutation is more likely to
genrate RF, and is more likely to put nosie on the apporpriate supply
line than an AC fan.
pointed out that AC fans have been used on solid-state
electronics
since the 1950s, he was unmoved and resorted to ad hominem attacks.
Where the hell do these ideas get started?
Probably from people who've never done 'real' electroncs. You know, the
sort that belive that the only thing you need to design and test
electronic circuits is a CAD workstation.
-tony