3b1 monitor switch (was UPS systems for the 3b1)

Gary S. Trujillo gst at gnosys.svle.ma.us
Sun Apr 8 14:53:25 AEST 1990


In article <22656 at rcsac1.UUCP> rhaar at rcsac1.UUCP (Bob Haar CS50) writes:
>
> How about posting a short "how-to" note. I would like to install a
> switch like this, but don't know which wire(s) to splice into. 

-------------------------------------------------------------------------------

>From the archives...  (I've deleted all but the relevant sections.
Apologies to Bill.)

| From: wtm at neoucom.UUCP (Bill Mayhew)
| Newsgroups: comp.sys.att
| Subject: Re: 3b1 Terminal & Scrreching Noise
| Summary: Usually not just the flyback is bad
| Keywords: Flyback transformer replacement?
| Message-ID: <1837 at neoucom.UUCP>
| Date: 23 Nov 89 04:30:53 GMT
| References: <1246 at adds.newyork.NCR.COM>
| Sender: wfd at neoucom.UUCP
| Organization: Northeastern Ohio Universities College of Medicine
| 
| ...
| 
| With monitors' penchant to fail in ugly ways, I opted to install a
| a separate power switch on the 12 volt power lead feeding the
| monitor on my 3b1 at home.  I soldered a wire to the fuse and
| another wire to the fuse holder and put a piece of tape between the
| fuse and its holder.  A switch is then attached to the free ends of
| the wires.  As such, the switch can be used to shut off power to
| the monitor while I'm not at home.  I drilled a 3/8" hole on the
| right bottom of the case for the shaft of a small Raido Shack
| toggle switch's handle.  On my monitor, there was plenty of room to
| install the switch.  Note that it is important that you put tape
| under only one end of the fuse when installing the switch so that
| the switch is wired IN SERIES with the switch so that you have
| continued fire protection.  Of course, if you are going to work on
| the monitor, unplug the machine from the wall and leave it off for
| 30 minutes before opening the case.  This is necessary to assure
| that any residual high voltage dissipates; even then, you should
| still presume that high voltage charge may remain.  Never work on
| anything electronic alone.  Have someone present to call for
| assistance if you are subjected to electrical shock.  One more
| safety issue is the display tube.  Hitting the tube may cause it to
| crack and subsequently impode.  Very serious injury can be caused
| by the flying glass of the implosion.  I have seen a CRT implode;
| it is VERY ugly.  You don't want to be in the same room if it
| happens.
| 
| If you have the type of monitor without the fuse holder, you'll
| need to splice into the power lead itself if you want to install a
| switch.
| 
| ...
-- 
Gary S. Trujillo                              gst at gnosys.svle.ma.us
Somerville, Massachusetts                     {wjh12,spdcc,ima,cdp}!gnosys!gst



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