HDTenEightyP/NetNews huggingface dataset:
From: paula@nlbbs.UUCP (Paula Stockholm)
Newsgroups: sci.electronics
Subject: VCR video head removal
Date: Wed, 06 Jan 93 04:34:24 GMT
Reply-To: paula@nlbbs.uucp
Distribution: world
Organization: The Electronics Workbench - Cumberland Maine


In article <C0D14L.Gnx@news.udel.edu> bew@brahms.udel.edu writes:

 > 
 > Hey, I am trying to fix this VCR and I have concluded that the video heads
 > must be worn down (the only way the picture is clear is if I put a lot of
 > back tension on the tape -- so much so that the sound starts to be effected).
 > 
        The head should come off after removing the two screws. Did you
        unsolder the little wires?

        They do make little pullers like gear pullers. If there are
        threaded holes in the top of the head cylinder, you might get a
        decent grip by threading a screw into these holes.

        Anyway, before you spend your money . . . if the heads work with
        high tension - the heads may be ok. The brake bands wear
        out, too. Did you start with a problem of not being able to view
        the pix in fast scan?  That's a brake band symptom.

        * * * * * * * * * * * * * *  * * * * * * * * * * * * * * *
	*   Paula Stockholm              paula@nlbbs.UUCP        *
	*  Cumberland, Maine          !nlbbs!paula@uunet.uu.net  *
	* * *  * * * * * * * * * * * * * * * * * * * * * * * * * * 

Newsgroups: sci.electronics
From: washer@sequent.com (Jim "Throw it over the wall" Washer)
Subject: How long should it take to erase a 705k1
Organization: Sequent Computer Systems, Inc.
Date: Tue, 12 Jan 93 21:40:57 GMT

Should it take more than 15 minutes to erase an hc705k1? 
If so, how long?
 - jim washer@sequent.com
From: whit@carson.u.washington.edu (John Whitmore)
Newsgroups: sci.electronics
Subject: Re: Microwave Oven Plasma Etcher? (definitions)
Date: 7 Jan 1993 21:31:28 GMT
Organization: University of Washington, Seattle
NNTP-Posting-Host: carson.u.washington.edu
Keywords: microwave, Reike and Hartree diagrams, Gerling Labs

In article <1993Jan7.005550.6869@kodak.kodak.com> ornitz@kodak.kodak.com (Barry x24904/ER/167B-TED) writes:
>In article <rich.726361718@pencil> rich@pencil.cs.missouri.edu 
>(Rich Winkel) writes:
>>Can anyone explain what a "Reike and Hartree diagram" is?
>
>A Rieke diagram is sort of a fancy Smith chart for representing how the load
>impedance and its point of connection to the magnetron can affect the power
>output of the tube and its frequency. 
	
	In the context of the original question (lowering the power
density in the microwave oven), this is irrelevant.  First, the
load is the contents of the microwave oven (and this can, we all know,
vary quite a lot without stalling the oven).  Second, we don't
care about the exact frequency (nor the exact power); only large 
power-output changes are of interest.
	The load would only change markedly if the feed horn
from the magnetron were altered.


>A Hartree diagram shows the theoretical minimum anode voltage at which operation
>is possible in the various modes of the magnetron.  Under operating conditions
>the anode voltage must exceed the values given in the diagram.

	This is obviously of concern.  I would have thought that the
magnetron was just a diode, and that changing the input current (by
substituting a smaller capacitor in the charge-pump power supply)
would alter the output power.  The implication here is that at too-low
voltages the magnetron doesn't oscillate.

	Again, I think this is not prohibitive: magnetrons are more than
85% efficient, and this implies that the input voltage (which is
unfiltered) is in the operating range for a substantial fraction of the
whole 60-Hz duty cycle.  That implies that the input voltage can vary 
by a factor of four or so before the magnetron stops oscillating.

	It might be impossible to get a 100:1 output power range, but
10:1 still looks reasonable.  As long as the magnetron doesn't overheat
from the current during the 'wasted' time, the microwave oven will
still operate even if the magnetron has output efficiency of zero
for most of the cycle.  It just means that the output power drops
to zero faster than proportionally to the input power.

	Think of it as reciprocity failure   :->

	John Whitmore
From: mycal@netronix.com (Mycal)
Newsgroups: sci.electronics
Subject: FM-10 FAQ (new version) 
Distribution: world
Date: Fri, 08 Jan 93 18:15:38 GMT
Organization: Netronix, Inc.


About the info packet, I have changed the price.  By putting most the
information I have in a packet it came out to 22 pages.  It cost me
$2.73 to print and send it. So I basically lost my butt on the first batch.

Anything postmarked after Jan 11 will have the following action taken:
if you send a buck you will only get the 3 amplifier plans.  Send $3 and
get the whole packet with other amp designes, BA1404-spec sheet, several
other BA-1404 based stereo broadcaster schematics, TV transmitter schematics,
and a couple pages on antennas.

Outside the US add $2(us funds only) for postage (3rd class).

Hope this doesn't cause many problems, but I gotta at least break even.

First batch of packets went out Jan 6th so you should be getting them
about the same time you read this.

slate,

mycal

-------------------------------------------------------------------------
Restrictions Suck!  Information is cool.                  |
Ignore info/freedom restrictors is the rule.              |
                                                        // \\
Your Pal Mycal -- mycal@netronix.com               Look 4 Gorilla TV!
Newsgroups: sci.electronics,misc.legal
From: cgordon@vpnet.chi.il.us (gordon hlavenka)
Subject: Re: Recommend a book on "Patenting Your Invention"?
Organization: Vpnet Public Access
Date: Mon, 11 Jan 1993 19:11:58 GMT

 kehoe@netcom.com (Thomas David Kehoe) writes:
>Would someone recommend a book about "How To Patent Your 
>Invention"?  There must be several available.

If you write to the Patent office in D.C. and ask them pretty much any
question about patents, they will send a booklet called "General
Information Concerning Patents" which has a lot of good information in
it.

You could also look in back issues of _Midnight Engineering_ magazine;
they've done a couple of case histories on the patent process.  (One
of them determined that it was better _not_ to patent, but instead to
protect your product as a trade secret.)

>I took Patent Law at the University of Chicago Law School, so I 
>know the theory.  I don't know what paperwork you file, how to do 
>a patent search, etc.

So what did they teach you? :-)

-- 
----------------------------------------------------
Gordon S. Hlavenka           cgordon@vpnet.chi.il.us
Vote straight ticket Procrastination party Dec. 3rd!
From: tjgerman@53iss6.Waterloo.NCR.COM (Trevor German)
Newsgroups: sci.electronics
Subject: MUSCLE WIRE
Date: 4 Jan 93 14:20:58 GMT
Organization: Imaging Systems Division, NCR Corp, Waterloo, Ont., CANADA


	Someone posted here the address where one can buy some of
	this stuff. I lost the post. Can someone please mail me
	the address.  Thanks


--
       >|  "Only average people            | Trevor J German BSc    |<
       >|        never make mistakes."     | NCR, Waterloo, Ontario |<
       >| tjgerman@53iss6.Waterloo.NCR.COM | Canada.                |< 
Newsgroups: sci.electronics
From: edotto@ux1.cso.uiuc.edu (Ed Otto)
Subject: Mail-Order Legal Covert Electronics (Where to Get)
Organization: University of Illinois at Urbana
Date: Fri, 8 Jan 1993 01:34:16 GMT

I need a suggestion:  I need to obtain a particular (legal) setup to
monitor conversations in my house to be tied into an alarm system, and
am unable to locate the neccessary small microphones to be used to detect
breaking glass, and pick up the noise involved in movement.

Anyone have any idea where these components may be obtained?  

Please note that I am looking for ASSEMBLED parts here, not the pieces to
construct my own.

					--		Ed

-- 
Edward C. Otto III			* e-otto@uiuc.edu
No one really knows...                  * edotto@ux1.cso.uiuc.edu
University of Illinois			* Voice: 217/333-9250
Printing Services Office		* Fax:   217/244-7277
From: pjs@gvgdsd.GVG.TEK.COM (Peter J. Stonard)
Newsgroups: sci.electronics
Subject: Re: TV delay lines distributors?
Date: 6 Jan 93 17:53:46 GMT
Organization: Grass Valley Group, Grass Valley, CA
NNTP-Posting-Host: gvgdsd.gvg.tek.com

In article <1993Jan5.165339.2659@vax1.mankato.msus.edu> 
ven0103@vax1.mankato.msus.edu writes:
>Hello!
>
>	Does anybody know a place where I can order delay lines for TV sets?
>
>	I need two different times delays:
>			1 micro second.
>			64 micro seconds. (There's one with 
>the reference DL710
>but a different one may work too.)

In a typical colour television set a one scan line delay (63.55us for
NTSC and 64.00us for PAL) is done with a glass block and acoustic 
transducers. Shorter delays of a few to a few hundred nanoseconds use
lumped constant LC 'all pass networks'. I'm not sure what you need to
do a 1 micro sec delay.

There is an alternative to the glass block by using a CCD delay
line and these are used in tv cameras and camcorders. They require
a clock which is often a multiple of the colour subcarrier frequency.

Anyway, my advice would be to find a service manual for a tv set,
and order 'spare' parts from the manufacturers parts warehouse or a
local tv/electronics parts shop that will special order these items.

The second suggestion is to find an old tv chassis and cannibalise it
for parts.

Either way the glass block delay line will require a matching coil at
each transducer so don't forget to order those too.

Finally, if you require a wide bandwidth through these delay lines or
low distortion due to ringing, the consummer tv grade parts may be
unsuitable. Professional analog tv equipment uses higher quality
delay lines which are more expensive.

++=++=++=++=++=++=++=++=++=++=++=++=++=++=++=++=++=++=++=++=++=++
Peter J. Stonard        +                                /^\  /^\
Grass Valley Group      +                       /^\     /   \/
Grass Valley, CA. 95945 +                     /     \ /    /  
pjs@gvgspd.gvg.tek.com  +     Fish keeper in the Sierra Foothills
++=++=++=++=++=++=++=++=++=++=++=++=++=++=++=++=++=++=++=++=++=++
If it looks like; sounds like; quacks like; an Opinion. It's mine.
Newsgroups: sci.electronics
From: cthomas@athena.mit.edu (Michael T Ford)
Subject: Re: broken switch on answering machine
Organization: Massachusetts Institute of Technology
Date: Thu, 7 Jan 1993 10:01:54 GMT

In article <1hq3gmINNpf4@samir.Warren.MENTORG.COM> samir@Warren.MENTORG.COM (Samir Agarwal) writes:
>I have this Radio Shack Duofone (tad-241) answering machine that has a
>knob on the rear to adjust the delay before the answering machine kicks
>in.
>This knob is broken and the answering machine never picks up.
>I opened up the machine and found that this thing looks like a potentiometer
>(but again it could be anything, I am not electronics savvy).
>Is there any way to fix this thing? I don't mind if the machine picks up
>immediately instead of several rings.
>Thanks,
> - Samir


I have that same answering machine.  I also got it and the pot was broken.
I did find that running two wires out to another pot worked quite well.
A 100Kohm pot seems to replace the other very well.

I think that they need to send the engineers back to the drawing board on 
that one.


73,
Mike



Newsgroups: sci.electronics
From: rubin@clam.cis.ohio-state.edu (Daniel Rubin)
Subject: Re: Where to mount an outside temp probe on a car?
Organization: The Ohio State University Dept. of Computer and Info. Science
Date: Tue, 5 Jan 1993 05:05:43 GMT

>>BZZZT!   He _wanted_ the air temperature -- which means he _wants_ _maximum_
>>"cooling" of the sensor.
>>
>
>Excuse me but if you cool the sensor by placing it in an airstream, your
>not reading the actual temperature of the air. Reading a sensor cooled
>by an airstream, by itself, tells you nothing. If you measure one sensor
>in an airstream and another one nearby but shielded from the air stream,
>you can determine the speed of the airstream. Other than that, I don't
>know why you would want to cool the sensor.

Hmmm...  You cannot get the probe any cooler than the temperature of the 
air flowing around it no matter how fast the air is flowing!  If anything
the friction of the air moving across the sensor would heat it up.  Now if
it is wet then the air will aid to evaporate the water on the sensor which
takes heat of evaporation from the sensor thereby lowering it's temperature.
Dry air flow around the sensor will not provide false readings unless 
excessive friction is created!  

							      - Dan
-- 

             Daniel Joseph Rubin     rubin@cis.ohio-state.edu 
     
                       GO BENGALS!      GO BUCKS!
From: worley@a.cs.okstate.edu (WORLEY LAWRENCE JA)
Newsgroups: sci.electronics
Subject: Re: nicads for Gameboy?
Date: 8 Jan 93 05:58:57 GMT
Article-I.D.: a.1993Jan8.055857.11399
Distribution: usa
Organization: Oklahoma State University

From article <93007.213229HCAMPBEL@vma.cc.nd.edu>, by H Campbell <HCAMPBEL@vma.cc.nd.edu>:
> In article <1993Jan5.042534.5631@cbnewsk.cb.att.com>, tbc@cbnewsk.cb.att.com
> (thomas.b.cook) says:
>>
>>The manual for Gameboy says not to use nicad batteries. I
>>called their hot line where I was told that this is because
>>the nicads can explode and damage the game. What are the
>>conditions where this is a concern? I have some ideas but
>>I'd appreciate the net.wisdom interpretation of this warning.
>>
> I had the same question and when I pushed for an answer they
> finally conceded that (1) the display would be slightly dimmer and
> (2) they were concerned that people would mix standard batteries
> with nicads.  They said that my game would not be harmed
> by using nicads and so far (6 months) they seem to be correct.

Ni-cads have a lower nominal voltage (1.2) than alkalines do (1.5), so if
you have 4 of them, you are almost a full volt less than with alkalines.
If the game will run ok with ni-cads, there's nothing wrong with using 
them.

-Jason
 
Newsgroups: sci.electronics
From: fossey@progress.COM (Paul Fossey)
Subject: PC Game Card
Keywords: ?
Organization: Progress Software Corp.
Date: Mon, 11 Jan 1993 12:59:01 GMT

I would like to use the PC Game Port on my PC to monitor outside world 
measurments such as temperature, humidity, barometric pres. etc. Does anyone
know how to construct resistive probes for these inputs, or where to purchase
these devices.



Newsgroups: sci.electronics
From: pdunster@cc.uow.edu.au (peter dunster)
Subject: Re: 9600 baud Modem design?
Organization: University Of Wollongong
Date: Mon, 11 Jan 93 23:44:46 GMT

nagle@netcom.com (John Nagle) writes:

>scottcr@wkuvx1.bitnet writes:
>>I am designing a custom 9600 baud link using a voice channel
>>with the following specs: BW: 100-5Khz  S/N = 35+ dB.
>>Are there any "rules of thumb" about choice of carrier
>>freq 2K ?  3k ?  What about FSK deviation?  With this
>>type of system how does modulation index affect performance?

>        I'd suggest getting the current Rockwell modem data products
>book.  There's probably an off-the-shelf single-chip solution to your problem.
>Try Rockwell Semiconductor Products at 1-714-833-4655.  Other
>manufacturers offer similar solutions.  Using a 9600 baud FAX modem
>part is probably the simplest way to go.  The channel you have is
>good enough.  FAX modems are half-duplex (one way at a time), so
>assuming you want a simplex channel (one way), this is the way to go.
>You avoid the complex bidirectional cancelling schemes used to push
>data in both directions simultaneously over two wires that are used to
>make 9600 baud data modems work.  Those modems won't work over a one-way
>link.

>					John Nagle

I used a Rockwell Fax chip a couple of years ago in a radio modem design, it
worked well and was easy to control, unfortunately before each transmission
of data it had to send a "training sequence" to get transmitter and reciever
into synch. This training sequence took almost a second, longer than the 512
byte packet that followed it and considerably longer than the returning 
"Ack" packet, thereby considerably reducing data throughput.

Looking through the data sheets, Rockwell do now have several 9600 Baud modem
chips which just need a few peripheral components to make a complete modem.

Pete Dunster

pdunster@cc.uow.edu.au
Newsgroups: sci.electronics
From: cthomas@athena.mit.edu (Michael T Ford)
Subject: Re: telephone ringer voltage
Organization: Massachusetts Institute of Technology
Date: Thu, 7 Jan 1993 11:31:12 GMT

In article <jecome01.726341429@starbase.spd.louisville.edu> jecome01@vulcan.spd.louisville.edu (Eric Comer) writes:
>I was wondering if anyone knew the voltage that is sent on the ringer
>line of a telephone cable when a call is incoming.  any help would be
>greatly appreciated.

The normal onhook voltage in the US is -48V.  When the phone rings
it is caused by a modulation of approximately 90-100 V at about 
20 (if I remember correctly) Hz.

73, 
Mike WZ0C
From: jmorriso@ee.ubc.ca (John Paul Morrison)
Newsgroups: sci.electronics
Subject: Re: High Efficiency Fluorescent Lighting   was:  Re: What really Failed on Fluorescent Lamp
Date: 6 Jan 93 02:29:28 GMT
Organization: University of BC, Electrical Engineering

In article <1993Jan5.055326.2966@klic.rain.com> keithl@klic.rain.com (Keith Lofstrom) writes:


[ high frequency flourescents ]
>
>I will second this.  I am running my large basement office with 120 watts
>into 4 tubes running off of two electronic ballasts.  It is very bright -
>perhaps too bright.  Much brighter than the 160 watts of T12 40 watt that
>used to be in here.  And brighter still than the 200 watts of rather dim
>incandescent that were originally in here.  No flicker or noticable hum,
>either (you can hear a slight hum if you park your ear right on the
>ballast).  They also turn on right away, unlike the sputtering startup
>of the old inductive ballast fixtures.

How much are the high-frequency ballasts, power conversion (60 Hz to whatever
kHz)?

And most of important, where do you get them? I strongly suspect the local
lighting hardware guys are going to say 'duuuuuhhh?' when I ask for this.

>
>Fiat Lux!
>
>Keith
>-- 
>Keith Lofstrom         keithl@klic.rain.com       Voice (503)-520-1993
>KLIC --- Keith Lofstrom Integrated Circuits --- "Your Ideas in Silicon"
>Design Contracting in Bipolar and CMOS - Analog, Digital, and Power ICs


-- 
__________________________________________________________________________
 John Paul Morrison                     |  
 University of British Columbia, Canada |  
 Electrical Engineering                 |   .sig file without a cause
 jmorriso@ee.ubc.ca              VE7JPM |  
________________________________________|_________________________________
From: abbasa@ul.ie
Newsgroups: sci.electronics
Subject: Re: WANTED: Info on printed circuit board layout software
Date: 4 Jan 93 01:06:52 GMT
Organization: University of Limerick, Ireland

In article <15176.2b33718d@ohstpy.mps.ohio-state.edu>, garland@ohstpy.mps.ohio-state.edu writes:
> I'd like to collect some opinions on printed circuit board layout software,
> with or without autorouting, to run on a PC. I've tried a shareware
> program called PCRoute, but it doesn't have enough flexibility. I don't need
> anything fancy (i.e., a la Autocad), and don't want to wade through a five
> hundred page manual and spend six weeks learning how to use it. Basically, all
> I need is capability for double sided boards, preferably with a silk-screening
> overlay.  Autorouting would be nice but not essential.  Thanks.
> 
> Jim Garland W8ZR
From: bame@hpfcbig.SDE.HP.COM (Paul Bame)
Date: Thu, 7 Jan 1993 02:38:20 GMT
Subject: Re: nicads for Gameboy?
Organization: HP SESD, Fort Collins, CO
Newsgroups: sci.electronics

In sci.electronics, tbc@cbnewsk.cb.att.com (thomas.b.cook) writes:


> The manual for Gameboy says not to use nicad batteries. I 
> called their hot line where I was told that this is because
> the nicads can explode and damage the game. What are the
> conditions where this is a concern? I have some ideas but
> I'd appreciate the net.wisdom interpretation of this warning.

> TIA,
> Tom

Warning or not, they work just fine.  Maybe the warning is because
the gameboy likes to place a short across the batteries now and then
but I've not had or seen any problems.

	-Paul Bame N0KCL
From: slmdj@cc.usu.edu
Newsgroups: sci.electronics
Subject: Re: MouseSystems Mice
Date: 7 Jan 93 16:51:38 GMT
Organization: Utah State University

In article <1993Jan07.145120.22489@uhura.neoucom.edu>, wtm@uhura.neoucom.edu (Bill Mayhew) writes:
> On converting Mouse Systems mice:  it depends...
> 
> The orginal Mouse Systems mice for the PC did have three buttons
> and used only a 200 cpi pad.  There were two versions of the three
> button mice.  "Very old" (~1987) units required a small battery
> eliminator transformer.  The slightly newer 3B mice were self
> powered.  (Incidentally, I suspect this might have had something to
> do with devices that are self-powered from the serial port; there
> is a patent out on the technique -- I forget who holds it at the
> moment.)  The three button mice send a five byte protocol that is
> the same as Summagraphics devices (and I think Logitech).


~1 year ago, I bought a _3-button_ Mouse Systems mouse for my PC... It also
came with an ?aluminum? mouse board.  The date of manufacture, I think, was
sometime in 1991.  Just a couple of questions on the general subject-- what is
the third (middle) button good for?  I have read the docs, but can't seem to
find anything pertinent.  

> 
> The newer Mouse Systems two button mice are self powered and use a
> three byte protocol that is the same as Microsoft mice.  The newer
> mice can sense either a 200 or 400 cpi mouse board.  There have
> been several different types of mouse boards: metal and plastic.
> The best boards were the 400 cpi boards that came with the later
> Sun-3 models (my opinion).  The mouse boards are available in
> several different sizes.  One used to be able to get mouse boards
> from Mouse Systems directly, but last time I talked to them, they
> didn't want to sell in less than OEM quantities.  I like the Sun
> verision that is about 15 cm * 15 cm.
> 
> I haven't had a chance to try out latest Mouse Systems PC mouse.
> It looks like it comes with a very high resolution board made of
> aluminum.
> 
> The only bad thing about MS mice is that I've had several old ones
> that blew a CCD line sensor.  I'd have thought the LEDs would go
> out, but I haven't had that happen yet.
> 
> 
> -- 
> Bill Mayhew      NEOUCOM Computer Services Department
> Rootstown, OH  44272-9995  USA    phone: 216-325-2511
> wtm@uhura.neoucom.edu (140.220.1.1)    146.580: N8WED

BTW-- I previously had a mechanical mouse that didn't work worth s**t.  To
anyone out there cursing your current mouse, you might want to look into one of
Mouse System's optical mice... Pure heaven after my previous mech. one!!!

-- 
********************************************************************************
      Paul Cowley      * ----looking for one of those spiffy quotations for my
   ==EE Undergrad==    * .sig...  Any Suggestions???
 Utah State University *
  C/A1C  CAP Utah Wing *
   slmdj@cc.usu.edu    *
********************************************************************************