HDTenEightyP/NetNews huggingface dataset:
From: v064mb9k@ubvmsb.cc.buffalo.edu (HELLO)
Newsgroups: sci.electronics
Subject: Need small tool to cut pcb board
Date: 5 Oct 92 18:24:00 GMT
Organization: University at Buffalo
News-Software: VAX/VMS VNEWS 1.41


  I am working on a device that I want to manufacture in short numbers.
The pc board dimensions are roughly 3*3 inches. Its much easier
to cut my own from stock. Is there a cheap or inexpensive tools that
could cut 1/16th inch double sided clad board neatly?

	Thanks indvance for any help
			Neil B. Gandler
From: vnelson@ccu.umanitoba.ca (Gerald Vernon Nelson)
Newsgroups: sci.electronics
Subject: Re: Need small tool to cut pcb board
Date: 7 Oct 92 02:22:32 GMT
Organization: University of Manitoba, Winnipeg, Canada


>>  I am working on a device that I want to manufacture in short numbers.
>>The pc board dimensions are roughly 3*3 inches. Its much easier
>>to cut my own from stock. Is there a cheap or inexpensive tools that
>>could cut 1/16th inch double sided clad board neatly?

I really don't see why you couldn't run it through a table saw or radial
arm saw.  Use a fine tooth blade for soft metals.

I use a radial arm saw to cut aluminum sheets, and it works pretty good.

Make sure you got a really good grip on the sheet.  Vice grips would help.

Vern Nelson
Newsgroups: sci.electronics
From: rainer@spot.Colorado.EDU (Rainer Malzbender)
Subject: Re: Infra Red Data Link: Need Help building one
Organization: University of Colorado, Boulder
Date: Tue, 6 Oct 1992 04:27:24 GMT

Missed the original question, but the current edition of RadioElectronics
has an article on an IR remote control project. Older issues of Elektor do
as well.
-- 
Rainer Malzbender
Post-doc, Physics
U. of Colorado, Boulder (303)492-1366           rainer@boulder.colorado.edu
From: Jason.Goga@mailbox.bison.mb.ca (Jason Goga)
Newsgroups: sci.electronics
Subject: DC to AC help
Date: 30 Sep 92  23:45:54 CST

 > Subject: DC to AC help
 > Organization: Malaspina College
 > Message-ID: <1992Sep28.095640.858@mala.bc.ca>
 > Date: 28 Sep 92 09:56:40 -0700

 > If I have a DC current how can I go back to an AC current???  This has
 > confused me greatly.  Can anyone help?
 >                        chris.

Chris,

I'm new to the echo, and hence may not be up on what yer level of expertese (sp?) is. However the basic idea with DC -> AC conversion is you need to turn the DC on and off, and work with the rough AC produced to form a wave that's acceptable.

For example you could stick a MOSFET in series with your DC load and switch it on and off, you'de get AC that way. (very very crude)

If you're powering an inductive (say a motor) or capacitive load and want a more smooth AC. You can use the reactive components of the load to smooth out a pulsating DC. You would do this with Pulse Width Modulation. First figure out the value of the sine wave at regular intervals, then generate a square-wave with a duty-cycle respective to that of the value for that time slice, and output this to a electronic switch. output that in turn to your load (you'll need to generate the othe half of the sine as we


ll but hey..)

If yer into analog stuffage, the output from a sine wave oscillator is AC, and the power you run it with is DC. Hence in a loose sense you have a DC to AC converter.

If you need gobs of power, use something switching for sure, unless you have heat-sinks the size of a Honda.

-Jason

---
 * Origin: C.A. - FrontDoor (1:348/207)
From: cyberman@toz.buffalo.ny.us (Cyberman)
Newsgroups: sci.electronics
Subject: Re: archive server for pa
Date: 5 Oct 92 23:27:11 GMT
X-Maildoor: WaflineMail 1.00r


   Mark Zenier was espousing about 'Re: archive server for pa',
   on [10-04-92  03:31] to All!
 MZ> At one time, there was a service called VideoLog that was
 MZ> piggybacked on one of the commercial services. (Compu$erve?).
 MZ> There are also CD Rom systems if you have a couple of kilobucks.

    What for the CD?  CD-ROMS drives are $200-$400 of course the
    software may be a different matter.

 MZ> In case you've missed the trend in the past decade or so, towards
 MZ> "Closer Customer Relationships", "Just in Time", and the rest of that
 MZ> package,  "They" don't want a lot of little customers, just big
 MZ> ones.  The money for sales support is going to go to the the things
 MZ> that make money.  And if this means ignoring a lot of small customers 
 MZ> in favor of a few big ones, well ...

    Actually thier big market is DISTRIBUTERS who mark things up
    for the little customers and provide a lot less support.

 MZ> Maybe they figure that if you don't have a couple of kilobucks to
 MZ> buy the CD Rom system, you aren't going to spend enough to be worth
 MZ> their while.

    This is what I call warm brown taste in mouth relations.  BAD
    all around.  What happens when the "little" guy becomes big?
    And they DON'T want to deal with them?  What goes around
    comes around alienated companies are "entities" run by
    poeple.  If you jerk the company you jerk the poeple.  This
    means those poeple WILL not deal with the company ussually
    again.  I've seen MANY poeple do this.

        Stephen Cyberman@Toz.Buffalo.NY.US
        Scripted at Mon  10-05-1992  17:39:37

... When you spit in the wind it comes right back at you.
--- Blue Wave/QWK v2.10
From: hoffberg@phebos.aps.anl.gov (Mike G. Hoffberg)
Newsgroups: sci.electronics
Subject: Re: Help! My CD player sk-sk-sk-sk-skips
Keywords: CD players, useful book
Date: 6 Oct 92 13:33:46 GMT
Distribution: usa
Organization: Argonne National Laboratory, Chicago Illinois

In article <1992Oct2.152431.10629@ip29!bob> kad@ip29!bob (Keith Drescher ip30) writes:
>
>But a caveat:
>I found a book on CD repair that tells how to do it right -
>          ^^^^^^^^^^^^^^^^^
>Keith Drescher

(since e-mail seemed to bounce)

What is the name of this book, and where do I find it?

MIKE
-- 
Michael Hoffberg               /.\ <Build APS>    "Jeez, am I the only  ~\   /~
hoffberg@phebos.aps.anl.gov   // \\ Argonne        one who paid full      \ / 
hoffberg@anlaps.aps.anl.gov  //_O_\\ National      price?" F.F.            | 
                            /__| |__\ Lab                  Obbyn! Obbyn!  _|_
Newsgroups: sci.electronics
From: agodwin@acorn.co.uk (Adrian Godwin)
Newsgroups: sci.electronics
Subject: Re: Personal recording device
Keywords: talking chips
Date: 28 Sep 92 12:21:23 GMT
Organization: Acorn Computers Ltd, Cambridge, UK

Rod Beckwith (rodb@slugo.corp.sgi.com) wrote:
#  Hello Anybody,
#  
#  I was down at the  Sharper Image store yesterday & saw a device that I
#  would like to know more about. I hope someone can help me.
#  
#  The device was a personal recording device. It is the size of a large pen
#  or penlight flashlight. You can record your voice onto a chip on one of two
#  20 second channels for playback later. I guess it is the same technology
#  used on newer answering machines. The company that manufactures these
#  things is Machina Inc. out of San Francisco.
#  

It probably uses the UM5100 voice processor IC from United Microelectronics.
This will digitise, compress and record speech into an attached SRAM, and
subsequently play it back.
It needs a certain amount of analogue support circuitry, mostly for recording
- a playback-only unit is a lot simpler. The only additional digital device
it needs is the SRAM.

-adrian

-- 
Adrian Godwin : agodwin@acorn.co.uk : adrian@fangorn.demon.co.uk : g7hwn@gb7khw
ObDisclaimer  : I believe this rubbish .. don't imagine that anyone else does.
From: rhaar@albert.cs.gmr.com (Bob Haar)
Newsgroups: sci.electronics
Subject: Re: Help! My CD player sk-sk-sk-sk-skips
Date: 5 Oct 92 18:30:37 GMT
Reply-To: rhaar@albert.cs.gmr.com
Organization: G.M. Research and Envirnmental Staff

In article 10629@ip29!bob, kad@ip29!bob (Keith Drescher ip30) writes:
|>I adjusted the tracking control on my 6 year old JVC unit last night.  
|>It did solve the intermittant tracking problem that I've been having
|>for a quite some time now.
|>
|>But a caveat:
|>I found a book on CD repair that tells how to do it right -

What book? And where did you find it?

|>so next week I'm going to put a scope on the thing and adjust it
|>to spec.  I read the book and decided that adjusting the tracking
|>control by the "guess" method wouldn't do any harm, just maybe put
|>my CD player out of comission until I could get a scope home.
|>A CD player is a fairly complex item though, there is the real chance
|>just twiddling any pot you happen to find might cause more harm than
|>good - be forewarned.


Maybe so, but the risk seems worthwhile to me. I got quotes from
several audio repair shops for a CD player that skips on the first
track (directory?) read - they varied from $65 to $95 just to brin the
unit into the shop and more if they had to take it apart. I so one
survey that said the average repari cost for a CD player is $170.
For a unit that cost $200 originally, I'll risk breaking it.





---
	Robert Haar               InterNet : rhaar@gmr.com 
	Computer Science Dept., G.M. Research and Environmental Staff
DISCLAIMER: Unless indicated otherwise, everything in this note is
personal opinion, not an official statement of General Motors Corp.


Newsgroups: sci.electronics
From: dgm@shell.portal.com (David G Metzger)
Subject: Re: PADS help needed .... 
Organization: Portal Communications Company -- 408/973-9111 (voice) 408/725-0561 (data)
Date: Sat, 26 Sep 1992 09:36:28 GMT

In article <1992Sep25.212257.5885@eng.ufl.edu> patrick@creek.eel.ufl.edu (Patrick Marchant) writes:
>Hi,
>
>I have recently downloaded the PADS programs and come some very
>strange errors and I am wondering if someone else has seen these
>errors also in the installation process. 
>
   [lines deleted]

>When I ran hardware setup program it gave me error saying 
>that it can not open "padsdemo\defaults.pds"
>
>Any help or suggestion is greatly appreciated.
>
>patrick@sioux.eel.ufl.edu
>

    The zip files have subdirectories, and you didn't use the "-d"
option of pkunzip to recover them.  The installation program can't find
the files and subdirectories for which it is looking and aborts.

--

-----------------------------------------------------------------
                                    Dave Metzger
                                    dgm@shell.portal.com
From: crichmon@sedona.intel.com (Chris Richmond)
Newsgroups: sci.electronics
Subject: Re: Information wanted about Pal/Gal/?
Keywords: EPLD, PAL
Date: 28 Sep 92 15:55:35 GMT
Reply-To: crichmon@sedona.intel.com
Followup-To: sci.electronics
Organization: Intel Corporation
Originator: crichmon@sedona


- lane@duphy4.physics.drexel.edu writes
- wlsmith@valve.heart.rri.uwo.ca (Wayne Smith) writes:
-> We are considering some small scale PAL/GAL development, and I was
-> wondering what is the lowest-cost PC-type development system.
-> The pal's/gal's would replace 7 to 10 conventional ttl chips which
-> currently perform 16 bit counting functions (straight counters and
-> programable interval timers) with multiple tri-state registers.
->

-74F525's make nice 16 bit count-down timers, but they're hard to get
-hold of.  Otherwise, you need some pretty fancy macrocell-type PALs to
-do the job.  I don't think you can do a 16 bit counter even in a 610:
-8 is about the limit.

I can only partialy aggree here.  I am not a PLD/PAL/Whatever logic
expert, but I know for sure that the EP6xx, 5C060, and many other
Intel/Altera macrocell type devices can do 1bit/macrocell syncronous
counters.  I have done this before and I am willing to mail anyone the
design file that is interested.

Chris
-- 
 Chris Richmond         |     Internet: crichmon@sedona.intel.com
 Intel, Corp. C3-21     |     Phone: (602)-554-8827
 5000 W. Chandler Blvd. |     This crazy is a world place. 
 Chandler, AZ  85226    |     My think losing I'm mind.
 
Newsgroups: sci.electronics
From: frank@rover.uchicago.edu (Frank - Hardware Hacker - Borger)
Subject: Re: Multimeters
News-Software: VAX/VMS VNEWS 1.41    
Reply-To: frank@rover.uchicago.edu
Organization: Joint Center for Radiation Therapy
Distribution: na
Date: Tue, 29 Sep 1992 14:16:00 GMT

In article <BvBIrC.A6v@cmptrc.lonestar.org>, neal@cmptrc.lonestar.org (Neal Howard) writes...
>I also recommend FLUKE. They may cost a little more than others, but you'll
>get your money's worth in accuracy, reliability, ruggedness and excellent
>factory service if you ever need it. My model 77 is going on 10 years old
>and is working perfectly. I blew it up once, when it was about 2 years old
>by accidently hitting it with over 1kv D.C plus God only knows how much R.F.

	We (read that I,) did a similar thing to a Fluke 4-1/2 digit dmm. It
	was reading the reservoir voltage on a high voltage thyratron when we
	cranked up the main HV. Only got RF to the fluke but it went south
	for the winter. Again cost about $30 to repair.

	Al did the same thing to his Data Precision. We fixed it in house, for
	a new fuse.

	That same fluke is subject to LDC screen failure after moderate drops,
	(waist high to floor.) Twice already in about 6 years.

	In summary, although we have only one fluke to go by, our Fluke has
	not really demonstrated ability to take lots of abuse. Other than its
	tendancy to go south for the winter under minor abuse, (and take a 
	loooong time to get fixed,) it is a very nice unit.

   Frank R. Borger - Physicist    __       Internet:  Frank@rover.uchicago.edu
Michael Reese - Univ. of Chicago |___      Phone : 312-791-8075 fax : 567-7455
  Center for Radiation Therapy   | |_) _   No man is good enough to govern 
                                   | \|_)  another man without that other's
    "Birthplace of Softball"          |_)  consent. - Abraham Lincoln
From: rwy@matt.ksu.ksu.edu (Robert Young)
Newsgroups: sci.electronics
Subject: Want an AD7569, where and $
Date: 2 Oct 1992 12:05:21 -0500
Organization: Kansas State University
NNTP-Posting-Host: matt.ksu.ksu.edu
Summary: Looking for AD7569 supplier
Keywords: part source

I'm looking for a supplier for the AD7569.  It is an 8-bit A/D and D/A in
the same chip.  I want one or two (not hundreds...).

Please suggest known suppliers.  Digikey, Jameco and Mouser are out.  I
haven't tried all the Newark distributors in my area but so far no luck
with them.

Reply to rwy@matt.ksu.ksu.edu

Thank.

Robert Young   rwy@matt.ksu.ksu.edu
Newsgroups: sci.electronics,comp.robotics
From: martinez@rodan.acs.syr.edu (Kenneth Mtz. (YONIX))
Subject: what is a MC68HC11EVBU
Originator: martinez@rodan.acs.syr.edu
Organization: Syracuse University, Syracuse, NY
Date: Mon, 28 Sep 92 08:51:58 EDT

 Any information on the above subject would be of great help. What are
they usually used for? Dimensions ? 

Thanx,
Kenn
Newsgroups: sci.electronics
From: henry@zoo.toronto.edu (Henry Spencer)
Subject: Re: Can despiking caps be connected to a central ground?
Date: Sat, 3 Oct 1992 23:40:22 GMT
Organization: U of Toronto Zoology

In article <jeremym.718096983@sfu.ca> jeremym@fraser.sfu.ca (Jeremy Thomas McDonald) writes:
>Do despiking caps need to go directly between the VCC and GND inputs
>of a given IC, or could they go between VCC of the IC and some central
>ground location, or even another IC's ground, for that matter?

The closer they are to being directly between VCC and GND on each individual
chip, the better.  The important thing to realize here is that wires have
inductance, and you want as little of that as possible in series with the
capacitor.  You want lots of little capacitors, with the shortest possible
leads, as close to the ICs as possible.

For most cases, it's adequate to set up a grid of power and ground wiring,
and spot despiking caps between power and ground at many places.  Common
practice on non-multilayer PC boards was to run VCC and GND buses side
by side underneath the DIPs:

     VCC| |GND
        | |
       +---+
       || ||
       || ||
       || ||
       || ||
       +---+
        | |
        | |
       +---+
       || ||
       || ||
       || ||
       || ||
       +---+
        | |
     VCC| |GND

and put a despiking cap directly across the bus pair at the head of each IC.
Don't forget to make the VCC and GND buses wide -- heavy wire or wide PC
traces -- to minimize inductance (and resistance too).
-- 
There is nothing wrong with making      | Henry Spencer @ U of Toronto Zoology
mistakes, but... make *new* ones. -D.Sim|  henry@zoo.toronto.edu  utzoo!henry
Newsgroups: sci.electronics
From: jbm@eos.arc.nasa.gov (Jeffrey Mulligan)
Subject: Re: Help! My CD player sk-sk-sk-sk-skips
Organization: NASA Ames Research Center
Distribution: usa
Date: Fri, 2 Oct 1992 01:27:35 GMT

I have this problem too.  I have a Scott unit that skipped a lot when
brand new.  I got it serviced under warranty, but had just moved and
didn't set it up for a while.  When I finally did, I discovered that
the skipping was better, but still occasionally skipped.  Interestingly,
it seems to skip more when the unit is cold, that is, it will skip
a lot when first turned on on a cold morning, but after an hour
or so it may play the same disk without skipping.

Having been disappointed with the "authorized" service, I will be interested
to hear any more suggestions about how to fix this.

-- 

	Jeff Mulligan (jbm@eos.arc.nasa.gov)
	NASA/Ames Research Ctr., Mail Stop 262-2, Moffett Field CA, 94035
	(415) 604-3745
Newsgroups: sci.electronics,rec.radio.amateur.misc
From: sysrick@orion.spd.louisville.edu (Rick McTeague)
Subject: Need: 12VDC 4A supply for 220V 50Hz
Date: Thu, 1 Oct 1992 13:33:48 GMT
Organization: University of Louisville

Can anyone recommend a good 12V DC supply which can deliver 3.5-4 Amps
continuously, and which will work off 220 Volt 50 Hz current? I have a
friend who wants to set up his parents in England with a portable NTSC
VCR and TV so he can send videotapes of the grandkids.

Right now, they're doing it by taking the battery out of the family car
(in England) and carrying it indoors... It's a real pain, and besides,
they sit it on a concrete floor and they're worried about it discharging.
[Urban legend alert!]

Oh - obviously, this has to be something available at a reasonable cost
(either here in the States or in England), shouldn't be too heavy, and
should already be in a case (as opposed to just a power supply which needs
to be put in a box).

Thanks in advance,
Rick
-- 

Rick McTeague
Electrical Engineering Department, Speed Scientific School
University of Louisville, Louisville, KY 40292
(502) 588-7020

Internet: sysrick@starbase.spd.louisville.edu

Disclaimer: I'm a stand-up comedian; if anyone takes me seriously, I'm
            doing something wrong!
From: Brian R. O'Hern (BRO'HERN)
Newsgroups: sci.electronics
Subject: TV input signal levels
Date: 29 Sep 92 11:06:27 GMT
Expires: soon
Reply-To: ohernb@lonexb.rl.af.mil
Followup-To: same
Distribution: na
Organization: USAF Rome Laboratory

I live in a fairly remote area, so I put up a General Instruments FM/VHF/UHF
antenna and pointed it right at the highest frequency station (68 ~795MHz).

To sum: every FM/UHF station within 150 miles is perfect (stereo, color,
bilingual).  Channel 68 had some color, stereo, but was very snowy.  I put
a broadband (DC-light almost) low noise/linear 30dB amplifier designed for
50 ohms in the line with everything below 600MHz filtered, and 68 was 
perfect. I didn't try to match 50 to 75 ohms.

The question is this:  the 68 signal level was about 150uV, the VHF stations
were all several mV.  If I take the filter out, the signals jump: 68 to 
several mV and others to 180+mV. The manuals for my TV and VCR don't specify
a max signal level, so I was wondering if anyone new what the largest signal
level (mV/dbm) a TV can handle without saturation or distortion or damage.
	(long story short)

BRO'HERN (Electronics Engineer)
____________________________________________________________________________
           STD DISCLAIM APPLIES ('disClaim dat I make is no lie...)
Unless otherwise noted, I say what I say about what I think or thought with
total disregard for what the U. S. Air Force says or thinks and vice versa.
You! Why, I aughta...
____________________________________________________________________________
Newsgroups: sci.electronics,rec.motorcycles,rec.radio.cb,rec.radio.swap
From: erc@unislc.uucp (Ed Carp)
Subject: Re: The Communicator
X-Newsreader: TIN [version 1.1 PL6]
Organization: Unisys Corporation SLC
Date: Tue, 6 Oct 1992 23:02:34 GMT

Dances With Bikers (blgardne@javelin.sim.es.com) wrote:

: jeq@i88.isc.com (Jonathan E. Quist) writes:
: 
: >I'll leave comments on the quality of
: >RS radios to those with direct experience.
: 
: "Quality" and "Radio Shack" are two concepts not often found in close
: proximity. I don't know about their two-way radios, but the RS weather
: radio I've got has much poorer reception than the promotional freebie
: weather radio my dad has. Strictly off the record, the local NOAA
: station said they get the most complaints about a "weak signal" from
: owners of RS models.

I haven't heard many complaints about the RS 2-meter rig.  Perhaps that's
because it's made by Icom, hmmm? :) :) :)
-- 
Ed Carp, N7EKG                  erc@apple.com                     801/538-0177
"This is the final task I will ever give you, and it  goes  on  forever.   Act
happy, feel happy, be happy, without a reason in the world. Then you can love,
and do what you will."           -- Dan Millman, "Way Of The Peaceful Warrior"
Organization: Sophomore, Electrical and Computer Engineering, Carnegie Mellon, Pittsburgh, PA
Newsgroups: sci.electronics
Date: Sat, 26 Sep 1992 17:33:16 -0400 
From: Liam David Gray <lg2g+@andrew.cmu.edu>
Subject: IBM PC joystick port address?

Hello.  I'm trying to read the my PC's analog joystick port. 
Unfortately, I've not used this port since BASIC, and my BASIC had
joystick primitives.

...Hence these questions: 
    -What's the address of the port?
    -How many bytes am I concerned with here, and what gets returned in
each byte?
    -How many bits are used to represent each of the four stick positions?
    -How frequently can this port be sampled?
    -What's the typical range of input voltages on the input pins? 
Nominally, I'd guess it's ~0-~5V, right?

I'm thinking of using the joystick port to stuff some audio into my pc. 
If you've done this either this way, or serially, or parallely
(parallelly?), I'd appreciate any suggestions.  Also, I'd like to hear
any comments on making a better audio output -- serial or parallel. 
(Hmmm, how fast is the parallel port, tops?)

Thanks in advance.

Liam Gray

Newsgroups: sci.electronics