HDTenEightyP/NetNews huggingface dataset:
From: garyg@warren.mentorg.com (Gary Gendel)
Newsgroups: sci.electronics
Subject: Re: 12V Power Amplifier Design
Date: 28 Jan 1993 17:16:56 GMT
Organization: Mentor Graphics Corp. -- IC Group
Distribution: world
Reply-To: garyg@warren.mentorg.com
NNTP-Posting-Host: garyg.warren.mentorg.com

In article 93Jan27020811@wpi.WPI.EDU, lancer@wpi.WPI.EDU (Stephe Lewis Foskett) writes:
>>>>>> "tapscott" == Peter Tapscott <tapscott@parc.xerox.com> writes:
>tapscott> You have to be cautious about accepting wattage ratings from
>tapscott> car amps. The manufacturers frequently exceed the laws of
>tapscott> physics with their ratings.
>
>You mean my new Sparkomatic "Hi-Power" amp doesn't really deliver 100
>watts per channel?

Sorry I missed the start of the thread.  Back in the late 70's I owned a pair
of surface mount, bi-amplified car speakers.  They came with an amplifier that
supplied 80W per channel in a 8X12X4 box.  Many years later it died and I took
a look inside.  There was a DC to DC converter to provide the high voltage that
was required.  Each amp had 4 high-power transistors in parallel (with some
stabilizing resistors) for the output stage.  Turned up, I could still hear the
music comfortably, moving at 60 MPH with the top down.  I still miss the quality
of the sound from this speaker/amp combination from ADS.  I also believe their
160W claim, though I never cranked them full up.

Gary



Newsgroups: sci.electronics
From: schaerer@isi.ethz.ch (Thomas Schaerer)
Subject: Re: Power Supply Question
Organization: Swiss Federal Institute of Technology (ETH), Zurich, CH
X-Newsreader: TIN [version 1.1 PL8]
Date: Wed, 27 Jan 1993 08:30:40 GMT

NEIL GANDLER (v064mcqs@ubvmsb.cc.buffalo.edu) wrote:

:     Im designing a small power supply. I would like to know if using a 12v
: center tap transformer when full wave rectified and smoothed be more than
: 15 volts to allow a 12 volt regulator 7812 work properly. From my under-
: standing the 78 series regulators need a 3 volt difference atleast. 

The first you must do, is calculate your circuit. 

	You use a center-tapping-trafo. Therefore you have only lost
	of one powerdiode-forward-voltage. From 12VAC you can expect
	about 16VDC with the lost of the diodes forwardvoltage. But
	this is the peak-DC-voltage. The ramp-voltage is given by
	capacitor and the used loadcurrent. The lowest DC-voltage-point
	may be not lower than the DC-outputvoltage of the regulator
	and his worstcase-dropoutputvoltage. 

	The answer:	Yes you can need the center-tapping-trafo
			with 12VAC, but you must know the loadcurrent
			and then you must calculate the value of the
			smoothe-capacitor.

So, I hope I can help you.

Bye Thomas
Organization: University Of Toronto Computing Services.
Date: Friday, 22 Jan 1993 13:34:18 EST
From: <TSMIC@vm.utcs.utoronto.ca>
Newsgroups: sci.electronics
Subject: tv flicker

  Hi there,
   My parents television has developed a flicker. The set is about six
  years old, and color. After about 30 minutes of usage, the flicker
  vanishes and the picture returns to normal. Also, when first powered
  on, the flicker is constant for approx. five minutes. When present,
  the flicker turns the picture whitish, dullens the color, and the
  picture has about ten horizontal lines across itself (20 inch set).
  After the first half hour post powering it up, the picture is fine for
  the entire duration until the next powering on.

      Any ideas on what's wrong?
  Michael Stockus
From: kz08+@andrew.cmu.edu (Ken Zuroski)
Newsgroups: sci.electronics
Subject: need advice on computer fix
Date: 26 Jan 93 07:10:45 GMT
Article-I.D.: romulus.728068245.14740.0
Organization: Doctoral student, English, Carnegie Mellon, Pittsburgh, PA

Greetin's:

I have a Tandy 1400 laptop computer, dual disk drive, backlit LCD screen.
It's an obsolete beast, maybe 3 or 4 years old, but since I used it mostly
for word processing it fit my needs perfectly (semi-portable, etc.) 
Unfortunately the other night my wife spilled water on the LCD display
and shorted something out; the screen lost several "rows" of LCD's, thus
making reading your writing kinda difficult, if not impossible.

Now, I'd rather not buy a new computer right now, but the 1400 seems to
be discontinued and I'm not sure if I can get it fixed; and, if I could
get it fixed, I'm not sure I want to pay Radio Shack's fixit prices, since
basically all they have to do is remove the LCD screen as a unit and plug
another in (I've had the computer apart already and it's very easy to
replace. I also made note of the contacts on which several IC's are mounted
in the exact place where the water was dumped, so I have a good idea what
shorted out).

Question: if you were me and wanted to fix this thing, how would you go
about it cheaply? Should I find someone who knows how to troubleshoot
the circuitry to find out which IC's are burnt? Should and can I find
some mailorder place that sells LCD boards that would fit this computer?
Your suggestions are most welcome.

Thanks--

Ken

---
~~~~~~~~~~~~~~~~~~~~~~~~~~~
Ken Zuroski
Department of English
Carnegie Mellon University
Pittsburgh, PA 15213 USA
kz08@cmu.edu
~~~~~~~~~~~~~~~~~~~~~~~~~~~
From: mckillnm@unix2.tcd.ie (Marky Mark)
Newsgroups: sci.electronics
Subject: PLCC and DIP EPROMs : Pinouts Please !!!!!!!!!!
Date: 26 Jan 93 20:38:28 GMT
Organization: Trinity College, Dublin

I have an eprom programmer and I want to make a converter so
that the programer can program a PLCC device.

I would like to mimic a 27512 normal DIP device.  The numbers on
the PLCC device are 27512 - 25.  Could any one tell me a bit about this
chip ..... ie, it's programming voltage, etc.

I would also like the pinouts for the socket.

        *       ?
        | | | | | | | | |
      --                 --
      --                 --
      --                 --
      --                 --
      --                 --
      --                 --
      --                 --
        | | | | | | | | |


Is pin 1 at ? or *, and which way does numbering go CW or CCW ??


Could any fill the table out and mail it back to me ??


       DIP(27512)     PLCC(27512)
       Pin #          Pin #             Disc
=================================================
        1                               A15
        2                               A12
        3                               A7
        4                               A6
        5                               A5
        6                               A4
        7                               A3
        8                               A2
        9                               A1
        10                              A0
        11                              O0
        12                              O1
        13                              O2
        14                              Gnd
        15                              O3
        16                              O4
        17                              O5
        18                              O6
        19                              O7
        20                              CE
        21                              A10
        22                              OE/Vpp
        23                              A11
        24                              A9
        25                              A8
        26                              A13
        27                              A14
        28                              Vcc





                        Thanks VERY much,


                                Mark.
--
  _ _ _                 _ _ _                        |  mckillnm@unix2.tcd.ie
 ' ) ) )         /     ' ) ) )    /     /) /)        |-------------------------
  / / / __  __  /_      / / / _  /_ o  // // _  __   |As they say in Russia ..
 / ' (_(_(_/ (_/ <_    / ' (_(__/ <_(_(/_(/_(<_/) )_ |    "Mascow...."
From: andywang@crown.berkeley.edu (Andrew Wang)
Newsgroups: sci.electronics
Subject: Re: SOA Sound Chip wanted for uProc Card
Date: 24 Jan 1993 01:55:25 GMT
Organization: University of California, Berkeley
NNTP-Posting-Host: crown.berkeley.edu
Keywords: D/A FM Synth Sound Music Speech

u009@csx.cciw.ca (G. Stewart Beal) writes:

>I'm looking for suggestions for chips to look at for a sound I/O project
>for a small Micro. I've got limited space for glue chips so I'd like to
>find something with a fair bit of smarts at the interface side. I know
>very little about the devices in use on cards like the Sound Blaster but it
>seems the volume of glue there indicates somewhat older parts. I'd like to
>generate stereo, of course, and have the capability of a D/A type path
>(CODEC or not) for speech, as well as the standard noises produced with
>synthesis techniques.
>If I can't find the info, I'll probably use a couple of 558's or the
>PM7528 mentioned by an earlier poster.
>I'd like to hear your suggestions for chips to use. I'll have reasonably
>standard AT type interface signals, but I've only got a space 75 by 80 mm
>or so in size, so standard cards are out of the question.

I was also looking for a sound chip similar to or somewhat simpler
than you describe. Didn't have too much success. Here's what
I found:

Simple three-channel sound chips like the one that was found in the
Commodore 64 are very hard to find now, having been obsoleted by
their manufacturer. Some that fall into this category:
General Instrument AY-3-8910, AY-3-8912, Mostek 65??

Low cost sound generators for simple consumer applications are hard
to find. Applications include appliances, automotive, and medical 
devices.  The ones I could find from the 1992 IC master are:
Siemens SAB0800 (replaces SAE series) 3-tone chime. Specifically
inteded for a doorbell, but has other uses.
Samsung KS-something: Single chip song players.
Unicorn Micro: Claims all listed in 1992 IC Master are obsolete,
don't know if they are any replacements and don't know whether
chip designs have been transferred to another company.

Lower end music chips for PC's: The Adlib and the Soundblaster share
the same FM-synthesis chip. Its type, I think, is OPL-3 meaning it can
do a 3-operator FM-sysnthesis function. I think it has 11 channels,
but I'm not sure what its limitations are.  The newer sound boards
like the Soundblaster Pro use an OPL-4 chip, also from Yamaha.
Unfortunately I don't know the number of the chip, and it's
difficult to get information from Yamaha.  The list of sound chips
provided by a distributor did not mention the FM chips. Also, I
looked on an Adlib board; the numbers were sanded off. If you
do find the number of this chip, I'll try to get some data on it.

Another interesting chip was shown at COMDEX. I'll look it up and
post some data. Do you have any info on the PM7528? I missed the
earlier post.

If anyone has more info about low-end chips, please tell me! I
am looking for prices in the $3 range. (qty 100)

Andrew

Newsgroups: sci.electronics
From: kez224@gemini (Never send a monster to do to work of an evil scientist.)
Subject: vortrax
News-Software: VAX/VMS VNEWS 1.41    
Organization: State University of New York at Albany - CSC
Date: Wed, 27 Jan 1993 04:39:00 GMT

Remember the Vortrax SC-01 speech chip? I need some, I found one in an old
project. Where can I buy more?
Also, Does anyone have a data sheet on this thing?
Ken
From: scottcr@wkuvx1.bitnet
Newsgroups: sci.electronics
Subject: Re: RADAR, RADAR ECM, and RADAR ECCM
Date: 21 Jan 93 18:22:13 CST
Organization: Western Kentucky University, Bowling Green, KY

In article <107823@bu.edu>, uni@acs.bu.edu (Shaen Bernhardt) writes:
> 
> originally I sent this as a letter, but it occurs to me that I might be
> mistaken on some points, or might have some points that others might
> like to hear so....:
> 
>>To: jcborkow@trident.usacs.rutgers.edu
>>Subject: Re: RADAR, RADAR ECM, and RADAR ECCM
>>Newsgroups: sci.electronics,rec.autos.driving
>>In-Reply-To: <Jan.20.12.40.11.1993.25528@trident.usacs.rutgers.edu>
>>Organization: Boston University, Boston, MA, USA
>>Cc: 
>>Bcc: 
>  
> In article <Jan.20.12.40.11.1993.25528@trident.usacs.rutgers.edu> you write:
>>
>>
>>     I am currently an electrical engineering student with a vast
>>interest in Microwave Engineering and RADAR Systems Engineering.
>  
> [Stuff Deleted]
>  
> It's nice to see someone else interested in this material.
> I have studied the functionality and process of speed measurement by
> radar for some time (Being an avid speeder)
> I bought my first radar gun (never had or tried to get a license) when I
> was 14.  
>  
>>                                                   Jason
>>                                   (jcborkow@trident.usacs.rutgers.edu)
Question:

Since the radar is Doppler based; wouldn't the ECM device have to be
a transponder... with fast phase lock, sythesize pulses with the proper
offset frequency to correspond with the desired readout speed, and
transmit this with enough signal to prevent capture of the reflection?

Hmmm...  
-- 
Chris Scott,  C/E Public Radio,  Western KY Univ,  (502) 745-3834
SCOTTCR@WKUVX1.BITNET      fx off: 745-2084     fx hm: 781-1232  
Newsgroups: sci.electronics
From: hinz@bonfire (David Hinz (hinz@picard.med.ge.com))
Subject: Re: XILINX XC2064-50
Organization: GE Medical Systems, Magnetic Resonance
X-Newsreader: TIN [version 1.1 PL8]
Date: Mon, 25 Jan 93 07:37:39 GMT

Jerry Szopinski Mfg 4-6983 (szopinsk@picard.med.ge.com) wrote:

: There is a very handy reference available called IC Master.  The ancient set
: that I had was a two volume set with supplements; I believe the current set
: is in four volumes plus supplements.  It should be available at your univer-
: sity's library.  If not, you may be out of luck because they are very 
: expensive, very few people privately own them; their cost is even prohibitave
: to some corporations.

You can sometimes get an outdated set from someone who has bought a new one,
look to rich companies with big engineering budgets for this.  This is also
a good method to get almost-new Thomas Registers, an 8-foot wide hi tech
yellow-pages.  All  you need now is to find that source....or was it a 
drain or a gate?

Dave

--

Dave Hinz  -  Opinions expressed are mine, not my employer's.  Obviously.
Ask me if I have an opinion on this! \ Don't blame me; I voted for Perot!
SAAB - Because you get what you pay for.     \       Pherrets are Phun!!!
Newsgroups: sci.electronics
From: phr@telebit.com (Paul Rubin)
Subject: Re: Wanted : Nicad Charger Plans
Organization: Telebit Corporation; Sunnyvale, CA, USA
	<1juf3rINNlbd@rave.larc.nasa.gov> <21186@acorn.co.uk>
Date: Thu, 28 Jan 1993 05:52:19 GMT

Little known battery secret: recharging zinc carbons actually works
well enough to be worthwhile if you recharge *before* deep discharging
the cells.  They won't hold the charge for a long time but for applications
like a bike headlamp that you use every night, you can save some $$
this way.
Xref: sparky sci.electronics:23149 rec.radio.amateur.misc:22882
From: klimasewski@fccvde.enet.dec.com (My name is...)
Newsgroups: sci.electronics
Subject: WEFAX/PRESS PHOTOS
Date: 25 Jan 93 19:50:40 GMT
Organization: Digital Equipment Corporation


This will interest those that have a Satellite Dish (TVRO)

Over the weekend I was successful in copying wefax pictures (S3 ch17 @1.88 and 
1.93MHz) and Press Photos on K2.

The demodulator and software is made by SOFTWARE SYSTEMS 
CONSULTING, called WEFAX/GOES. It consists of a piece of hardware that 
connects to the end of an RS232 cable. The hardware has two cables with 1/8th
plugs. One for HF fax and the other for VHF. This plugs into the ext. speaker
jack.

I connected the descrambler output port of my receiver which is a 0-8MHz video
output port to the rf input port of a shortwave receiver that has an 
FM mode and tuned in the freq range of 1.88MHz,1.93MHz (S3) and 4.020MHz (K2). 

Pictures looked great! Has anyone else tried this using a TVRO??


                             Ken
Newsgroups: sci.electronics
From: Curt.Miller@launchpad.unc.edu (Curt Miller)
Subject: computer control of stepper motors
Organization: University of North Carolina Extended Bulletin Board Service
Date: Wed, 27 Jan 1993 03:13:43 GMT

	I was wondering if anyone could please point me to some good
articles, magazines, or books that would deal with the topic of controling
stepper motors with a computer, preferably a MSDOS based PC compatable
type system.  I am looking for hardware configurations and software 
drivers.  Any help would be appreciated.

	Please mail replies to the address listsed below, since 
	the site I currently read news at is temp. having problems.
	I will forward any responces to any interested parties.

UCSKJM@UCS.UWPLATT.EDU		Kurt Miller
UCSKJM@UWPLATT.BITNET	Univ. of Wisconsin Platteville
 


--
   The opinions expressed are not necessarily those of the University of
     North Carolina at Chapel Hill, the Campus Office for Information
        Technology, or the Experimental Bulletin Board Service.
           internet:  laUNChpad.unc.edu or 152.2.22.80
From: rose@bucknell.edu (philip rose `94)
Newsgroups: sci.electronics
Subject: Re: My TV is in a funny spot.
Date: 22 Jan 1993 17:02:58 GMT
Organization: Bucknell University, Lewisburg, PA
Distribution: world
NNTP-Posting-Host: canopus.cs.bucknell.edu

In article <1349.442.uupcb@ozonehole.com>, gerald.belton@ozonehole.com (Gerald Belton)  writes:

|> A while back there was a company marketing something called the "VCR
|> RABBIT."  It is/was basically a small UHF transmitter that would
|> broadcast the output from your VCR so you could watch it on other TV
|> sets around the house.
|> 
|> I bet your neighbor has one of these.  He probably has a switch box with
|> the satellite reciever, cable box, VCR, and Genesis game as inputs.  The
|> output goes to the transmitter and his main TV.  Your TV is picking up
|> his signals.

The VCR rabbit doesn't broadcast the signal.  The signal is sent through 
a narrow bandwidth pair of wires (called miniwire or something like that).

-------------------------------------------------------------------------------
Phil Rose
rose@coral.bucknell.edu
From: boots@watnxt11.ucr.edu (k steven thomas)
Newsgroups: sci.electronics
Subject: Info on clock NEEDED
Date: 27 Jan 93 06:09:33 GMT


I'm not electronically inclined, so I was hoping someone could help me solve
a problem.  I recently removed the long-dead clock from my 1977 280Z, and 
checked it out. The wiring to the clock is carrying 12 volts (as it should),
and there is continuity between the power lead and the ground lead on the 
clock. When 12 volts are sent through the clock, the magnets twitch slightly,
but don't run at all. I know that in water pumps (my line of work) the magnets
can wear out or there can be a problem with the coil. Is it the same with the
clock?  Or is it the electronic components (transistors, capacitors, God knows
what else) ?

This clock seems like a real simple device, but I haven't been able to locate
one that works in four years of searching. If you can help me, please e-mail 
me since this is a personal problem and I don't want to bother the group.

Thanks a lot.

-Boots.

boots@watserv.ucr.edu
Newsgroups: sci.electronics
From: Ed Neubauer <neubauer@neptune.iex.com>
Subject: Telephone Off Hook Capture Circuit
X-Xxmessage-Id: <A7857E7D420262F4@neubauer.iex.com>
X-Xxdate: Fri, 22 Jan 93 10: 35:41 GMT
Organization: IEX Corp.
X-Useragent: Nuntius v1.1.1d9
Distribution: us
Date: Fri, 22 Jan 1993 16:31:11 GMT

I looking for a circuit design toperform the following telephone function:

Security systems which automatically dial out to report a disturbance
use some sort of telephone line device which automatically "captures"
the telephone line.  At the moment the Security System itself goes
Off-Hook 
to prepare to dial out, the line capture circuit automatically senses Off
Hook 
and disconnects any extension telephones that may be off-hook.  Then the 
circuit regains a dial-tone by switching the telco line to On Hook for a
second 
and then goes back Off-hook to allow the security system to dial out.

Any ideas?  Thanks, 

=========================================
Ed Neubauer          
Plano Tx
Email: [uunet!]iex!neubauer or neubauer@iex.com
=========================================
From: pkbhatti@kopth004.delcoelect.com (Pardeep K. Bhatti)
Newsgroups: sci.electronics
Subject: Re: Why do solder joints go bad?
Date: 20 Jan 93 17:42:56 GMT
Organization: Delco Electronics Corp.

In article <77230005@teecs.UUCP> smithr@teecs.UUCP (Robert Smith) writes:
>I agree with Jerry, usually solder joints have the seeds of failure
>implanted during manufacture. If the joint is protected from the
>atmosphere it shouldn't go bad. Thermal expansion will not kill a well
>made joint; we thermally shock all our products from +85C to -40C with
>a transition of about 4 seconds for 30 cycles to test solderability.

"Experience has shown that most of these failures are produced by a
mismatch in the thermal coefficients of expansion (TCE) of the different
types of materials typically used in electronic assemblies." -- quoted
without permission from "Cooling Techniques for Electronic Equipment"
by Dave S. Steinberg, a foremost industry expert on reliability issues,
page 249.

"The standard mechanical reliability concern for solder joints is the
measurement of resistance to failure by low cycle fatigue due to thermal
cycling." -- quoted without permission from "Solder Joint Reliability",
edited by John H. Lau, page 267.

I can probably dig up dozens of quotes to this effect.

Thermal cycling is the primary cause of solder joint wear-out. Even a
well made solder joint has a finite thermal fatigue life. If you have
manufacturing defects, they make the problem much worse.

And thermal shock DOES NOT simulate thermal cycling. It does not allow
solder creep, which is the root cause of thermal fatigue and occurs over
much longer periods of time, several minutes to hours. In fact, the slower
you ramp the temperature and longer you hold at temp. extremes (upto a
limit), more you damage the solder joints. This is the nature of low
cycle fatigue and a well known fact, supported by theory and experimental
studies.

In general, solder joints in large surface mount devices (leadless being
worse than leaded) have a much shorter fatigue life than plated through
hole type devices. Since the current trend in the industry is towards
surface mount technology, solder fatigue will become more critical in
the future.
-- 
Pardeep K. Bhatti                         pkbhatti@kopth004.delcoelect.com
Delco Electronics Corporation
GM Hughes Electronics
***  The opinions expressed are mine, not necessarily of my employer.  ***
From: slmdj@cc.usu.edu
Newsgroups: sci.electronics
Subject: DC to AC on large scale???
Date: 21 Jan 93 09:52:54 MDT
Organization: Utah State University

While visiting my uncle in Calif. over Christmas break, he posed a question for
me... Just so I have an answer for him (and myself too... It's an odd one)
could someone help me out???

He is an assistant city engineer for Adelanto, CA, and told me that the way
their power is distributed to a large substation is Direct Current!  He said
that the DC is then 'phased' or 'converted' so that there is a three-phase AC 
line to the city distribution grid.  Neither of us have any idea how this could
be accomplished at such power levels (an entire valley, I think!)

Thanks, 
-- 
********************************************************************************
      Paul Cowley      * ..."It's easier said than done."   And if you don't 
   ==EE Undergrad==    * believe it, try proving that it's easier done than
 Utah State University * said and you'll find that 'it's easier said that "it's
  C/A1C  CAP Utah Wing * easier done than said" than it is done.'  Which really
   slmdj@cc.usu.edu    * proves that it's easier said than done.
********************************************************************************
Newsgroups: sci.electronics