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Date:      Mon, 1 May 2000 15:33:57 -0700 (MST)
From:      "Chad R. Larson" <chad@DCFinc.com>
To:        freebsd@gndrsh.dnsmgr.net (Rodney W. Grimes)
Cc:        dr@dursec.com, kpielorz@tdx.co.uk, djb@ifa.au.dk, smp@csn.net, smp@FreeBSD.ORG
Subject:   Re: hlt instructions and temperature issues
Message-ID:  <200005012233.PAA18008@freeway.dcfinc.com>
In-Reply-To: <200005011814.LAA01684@gndrsh.dnsmgr.net> from "Rodney W. Grimes" at "May 1, 0 11:14:39 am"

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As I recall, Rodney W. Grimes wrote:
> Right along with the chain breaking/hammer bank smoking code for the
> 1403 printers....  basically a very specific sequence of lines with
> very special character sequences could cause 1/3 of the hammer bank to
> fire every 14uS or so, do that for more than 10 cycles or so and you
> could litterly break the print character chain.  De-optimize it for
> chain breaking and run it for 10 minutes and you would start smoking
> the hammer coils....

Ah, yes.  I had one that would play "The Iowa Fight Song" (I was
working for Collins Radio in Cedar Rapids at the time--circa 1969).

Worked best with a single sheet of paper, and the paper thickness
set for 6-part forms (very rattley).   And the feed clutch
open, so you could use "line feed" as a drum-beat.  We had a printer
controller (built by Collins, the 8401 I believe) that would allow
you to gang printers, in case you needed more than 6 copies.  Get
five or six printers going and you could hear the song all over the
building.  I seem to remember one of my cow-workers wrote "On
Wisconsin" as well.

But shattering the chain was pretty spectacular.  You'd want to be sure
the covers were down or someone could get hurt.  The IBM CEs loved us.

Sometime I should tell you about making the Bryant disk drives walk
across the floor...

	-crl
--
Chad R. Larson (CRL15)   602-953-1392   Brother, can you paradigm?
chad@dcfinc.com         chad@larsons.org          larson1@home.net   
DCF, Inc. - 14623 North 49th Place, Scottsdale, Arizona 85254-2207


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