From: szekeresREMOVE@pitt.edu (GregS)
Subject: Re: Quieting all these fan motors
Date: Fri, 13 Sep 2002 16:49:53 GMT
NNTP-Posting-Date: Fri, 13 Sep 2002 16:46:57 +0000 (UTC)
X-Newsreader: News Xpress 2.01
In article , "George Gonzalez" wrote:
>I'm surrounded by an embarrassment of riches- lots of older
>(1960-1980) test equipment.
>These nice old doohickeys are just right for my relatively modest
>needs-- just enough performance,
>nice big knobs, when they go sick, they're mostlty easily serviced.
>But most of them have one annoying design quirk---
>THEY MAKE A LOT OF NOISE. From their fans, mostly.
>If I turn on the Tek 76xx rack-mount scope, I get a buzzy hiss.
>I usually use the silent 5000-series scope, but if I need more than 2MHz
>of bandwith, I need to power-up the buzzmaster-7000.
>Then I need to check a capacitor labeled "120". Is it 12pf, or 120?
>Only the old HP cap meter can tell, and it adds a more "wooo-wooo" to the
>Then I need to blow up a shorted tantalum in this Tek 475 scope,
>(well, actually, it turns out to have FOUR shorted caps), so I need
>to turn on the 0-40V, 0-10Amp power supply. It adds a rattly hiss to the
>On rare occasions I need to also measure a frequency to many digits,
>so I turn on the 5360A computing counter. I don't begrudge it having a big
>fan, as it must contain 300+ TTL IC's (and not LS TTL either). But that fan
>would blow off my soon-to-be-needed toupee, it's just too much to stand for
>any length of time.
>I'll soon be trying to resuscitate a PDP-8/E, which IIRC has at least three
>Any one of those fans, I could stand for a short time, but all of them is a
The more things you turn on, the less each will matter.
This reminds me what it was like working in a large room with some
big under floor air handling. Was a Nasa tracking station actually
Good ol days.
I'm still using PDP Linc Eight fans in a number of equipment.