HDTenEightyP/NetNews huggingface dataset:
From: moisan@silver.lcs.mit.edu (David Moisan)
Newsgroups: sci.electronics
Subject: Realistic VCR will not load
Summary: Realistic #20-518 VCR refuses to load tapes
Keywords: vcr loading problem
Date: 7 Jan 93 14:19:03 GMT
Followup-To: poster
Distribution: na
Organization: MIT Laboratory for Computer Science
NNTP-Posting-Host: silver.ai.mit.edu

Hi!  I've a problem with a Realistic #20-518 VCR that refuses to 
load a tape.  It's a late-model VCR, employing a quick-start 
(partial-loading) mechanism.

The VCR--a neighbor's--came to me a few months ago with a munched
tape (a rental :();  apparently the tape had incompletely loaded
and the M-guides yanked the tape out, mangling it.  Upon inspection,
I found a broken gear in the loading mechanism.  (It meshes witha 
a rack that moves the loading tray.)

After a few months of wrangling with Tandy Parts (while they sent me
the wrong ones, but let's be fair, I had no service manual), I got the
gear and replaced it.  The machine now will not load a tape.

The mechanism (basket and gears) moves a few mm. then stops.  There's
no obvious jam-up.  Is it an alignment problem caused by the broken gear?
Or is it a problem that _caused_ the gear to break in the beginning?
 
I'd like to know.  Any informed assistance is much appreciated.
 
Dave


-- 
| David Moisan, N1KGH    /^\_/^\   dmoisan@pro-angmar.alfalfa.com |
| 86 Essex St. Apt #204 ( o ^ o )  moisan@silver.lcs.mit.edu      |
| Salem. MA 01970-5225     | |                                    |
\-----------------------------------------------------------------/
Newsgroups: sci.electronics
From: sjacobi@mailbox.fwrdc.rtsg.mot.com (Sidney Jacobi)
Subject: Re: 74HC4046 help required.
Organization: Fort Worth Research and Development Center, Motorola, Inc.
Date: Fri, 8 Jan 1993 19:24:05 GMT

In article <1993Jan6.132039.26487@cs.ucf.edu>, clarke@acme.ucf.edu (Thomas Clarke) writes:
> In article <1993Jan6.033742.14845@news2.cis.umn.edu> Mike Diack  
> <mike-d@staff.tc.umn.edu> writes:
> > In article <7116@m1.cs.man.ac.uk> Mark Robinson,
> > mark-r@spec0.ee.man.ac.uk writes:
> > >If anyone has a datasheet for the 74HC4046 PLL chip handy would
> > >you let me know how the frequency of the VCO is related to the
> > >values of R's and C and the max/min values that they can take.
> > >
> > >I want to run it with a lock range of about 1MHz, centred on
> > >8MHz, but the equations in the Maplin catalogue don't allow
> > >frequencies >2.8MHz (R=5k, C=50pF; ie the minimum allowed) even
> > >though they claim the VCO can get up to 15MHz. I think their
> > >data must be for the 4046 and none of our databooks are modern
> > >enough to include the 'HC4046 :-(
> > 
> > Something you should be aware of is that all HC4046's are NOT 
> > created equal. Two extremes I have found are
> > 1 : An SGS device that was barely able to oscillate at  1 MHz
> > (and the output waveform was triangular at that frequency)
> > and -
> > 2 : An RCA device that was still producing respectable square
> > waves at 10 Mhz
> > (Both devices running into a scope probe only , 5 volt supply)
> > 
> > At the frequency you want (8 Mhz) the design nomographs
> > become a bit irrelevant, as internal Cs & Rs dominate the issue.
> > 
> > I was driven to using LS124/324s, but i only wanted the vco
> > function, no doubt someone makes a better PLL.
> > cheers,
> Look at the Signetics NE564 - son of the old 560/1/2 .  It is a 
> PLL that gets up to about 30 MHz and has a TTL buffered output!
>

     You might want to take a look at the Motorola version of the 
54/74H4046. I have used the device in various circuits in a commercial
cellular application, and found them to be very stable. 
Newsgroups: sci.electronics
From: ajackson@ernie.Princeton.EDU (Andrew William Jackson)
Subject: Re: Magnetic Sensor?
Originator: news@nimaster
Organization: Princeton University
Distribution: world,local
Date: Mon, 11 Jan 1993 05:25:13 GMT

In article <1993Jan2.104609.4196@arizona.edu> dparker@ece.arizona.edu (Douglas R. Parker) writes:
>Greetings.
>
>Quite a while back I attempted to repair the tape deck
>in my Toyota. I found that one of the plastic shafts that
>rotates the casette's tape wheel had cracked, leaving a gap
>in the gear teeth. I assume the reason for malfunction and
>subsequent devouring of many a tape was a perpetual End of
>Tape being recieved. I tried using similar salvage parts to
>replace the gear but this didn't work. The reason for this,
>I think, is that the original gear had a small disk magnet
>fixed to its base, and beneath it was a small surface mount
>component. I assume this is some sort of a tape speed
>regulation. My question? The matter is rather academic at this
>point, as this was a good excuse to buy a CD unit. However,
>I am still very curious as to how the thing worked. Although
>my EMAG is rusty, I would guess that a rotating B field was
>somehow used to induce current in this sensor, which was
>then used as a feedback. Does anyone out there have experience
>with this type of arrangement?
>Just extremely curious,
>

more likely a hall effect sensor.
From: wtm@uhura.neoucom.edu (Bill Mayhew)
Newsgroups: sci.electronics
Subject: Re: microphone circuit
Date: 5 Jan 93 14:24:25 GMT
Organization: Northeastern Ohio Universities College of Medicine

The last time I watched a piano tuner in action, he used a strobe
disc to rough in the tuning.  The disc was in in a box with a neon
bulb apparently connected to the output of an amplifier.  The speed
of the disc was also regulated, as the box had a sharp/flat knob,
which the turner adjusted slightly sharp, a qualitative adjustment,
for the paino's upper registers.  He adjusted A 440 with a tuning
fork first, then worked up and down form there.  Final voicing was
done entirely by ear.

Given the the complex waveforms that most insturments genreate, the
stroboscopic disc is a really handy means for checking frequency.
I'd imagine that one could be more hip by replacing the neon bulb
(it was a lot bigger than an NE-2H) with an LED array.


-- 
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
Newsgroups: sci.electronics
From: agb@mentor.cc.purdue.edu (Sam Habegger)
Subject: Re: Problem with 68hc705 eval. kit
Organization: Purdue University Computing Center
Date: Thu, 7 Jan 1993 15:12:05 GMT

In article <1993Jan1.162603.6390@desire.wright.edu> cse0239@desire.wright.edu writes:
>I got the 68hc705kics kit and it seems to work correctly on everything
>except blank check of the part. Has anyone had success blank checking
>an erased part? 
>
>Could this be a problem with my I/O port?
>
>

Try a shorter cable between the printer port and the evaluation board.

On an XT compatible I had to use a long cable to run the simulator and
a short cable to get a successful blank check to program the eprom.
Newsgroups: sci.electronics
From: timd@fenian.dell.com (Tim Deagan)
Subject: Kearfot Variable Reluctance Stepper Motor
Reply-To: timd@fenian.dell.com
Organization: SLAMDANZ CYBRNETX
Date: Wed, 6 Jan 1993 15:54:10 GMT

HELP!
I have four gorgeous large stepper motors from old 8 inch
floppy drives.  They have cylindrical bodies (approx. 2.5"
long and 2" in diameter) with deeply threaded shafts (6 inches
long!!).

They were manufactured by SINGER and are labeled;
Kearfot Variable Reluctance Stepper Motor
They have four leads;
Black, Brown, Red and Orange
RE, OR and BR all have 32 ohms between any pair, BL has 18 ohms
between itself and any other lead.  (3 phase stepper?)
They operate on 12VDC.

I have been unable to make them go. :-(
Sequential stepping of the OR RE BR leads does not do anything
but make the shaft vibrate.

These look really torquey and I want to make them run!  Any info
would be VERY helpful.

aTdHvAaNnKcSe
--Tim
---
timd@fenian.dell.com-My employer is_not responsible for_this.
    / / | |     /  || \  / |  __  |  _ \  /  || \ | ||__ /
 ***\ \*| |___*/ /_||  \/  |*|__|*| |_) )/ /_|| |\| |*/ /_***
    /_/ |____//_/|_||_|\/|_|      |____//_/|_||_| \_|/____|



Newsgroups: sci.electronics
From: jhallen@world.std.com (Joseph H Allen)
Subject: Re: NTSC sync rate questions
Organization: The World Public Access UNIX, Brookline, MA
Date: Mon, 11 Jan 1993 21:55:35 GMT

In article <fXQx2bD@quack.sac.ca.us> mrapple@quack.sac.ca.us (Nick Sayer) writes:
>I have an NEC 5FG. It is a multisync RGB monitor. I also have the CPU
>boards for an arcade video game. It has NTSC timed analog RGB output.
>I want to know if the two will be compatable. I suspect they will, but
>I am confused:
>
>It's my understanding that the vertical retrace rate of NTSC is 60 Hz,
>and that it is interlaced, yielding 30 pictures per second. But the
>monitor says 55-90 Hz vertical sync rate. That sounds compatable
>to me.

Yes that's fine.

>It's my understanding that the horizontal retrace rate of NTSC is
>14 kHz.

It's 15.734 KHz.

>The monitor says that its acceptable range is 27-79 kHz.
>Now 14 x 2 is 28, but am I reading too much into that coincidence?

Yup.  It's not going to work.  There is something to the coincidence though:
640x480 VGA is what NTSC would be like if it didn't have interlace.  I.E.,
same verticle rate, double horizontal rate.

Now if you had an analog CGA compatible monitor, you could do it.
-- 
/*  jhallen@world.std.com (192.74.137.5) */               /* Joseph H. Allen */
int a[1817];main(z,p,q,r){for(p=80;q+p-80;p-=2*a[p])for(z=9;z--;)q=3&(r=time(0)
+r*57)/7,q=q?q-1?q-2?1-p%79?-1:0:p%79-77?1:0:p<1659?79:0:p>158?-79:0,q?!a[p+q*2
]?a[p+=a[p+=q]=q]=q:0:0;for(;q++-1817;)printf(q%79?"%c":"%c\n"," #"[!a[q-1]]);}
From: strong@tc.fluke.COM (Norm Strong)
Newsgroups: sci.electronics
Subject: Flywheel batteries
Date: 5 Jan 93 15:33:40 GMT
Organization: John Fluke Mfg. Co., Inc., Everett, WA

Well, I've read all the postings on what might happen if a car with a
flywheel power supply were to crash.  Unless catastrophic failure can be
avoided entirely, I would guess that flywheel power sources will be used
mainly to assist batteries with high specific energy, but low specific
power.  

A flywheel can be floated across the battery, providing high power when
needed, and being spun up again during periods of low power demand.  In
this use the flywheel will only be a tiny fraction of the size
contemplated in an all mechanical system, and the kinetic energy
dissipated during a failure will be correspondingly low.  
-- 

Norm Strong  (strong@tc.fluke.com)
2528 31st S.   Seattle WA 98144   USA
Newsgroups: sci.electronics
From: steveh@tasman.cc.utas.edu.au (Steve Howell)
Subject: Any manufactures of Digital Audio IC's
Organization: University of Tasmania, Australia.
Date: Mon, 11 Jan 1993 01:54:58 GMT


	Hello peoples..

I need info any any manufactures that produce IC's for audio applications like
digital sampling, digital effects and so..

I know boss (roland) makes heap.. but i think its in-house stuff only..

anyone have any idea's here?


Thanks
Steve H

Xref: sparky sci.electronics:22077 alt.cd-rom:5470
From: dherity@cs.tcd.ie (Herity D.)
Newsgroups: sci.electronics,alt.cd-rom
Subject: Re: chip vendor databooks/sheets/applic notes
Date: 6 Jan 93 11:40:14 GMT
Organization: Computer Science, Trinity College Dublin

kgdykes@thinkage.on.ca (Ken Dykes) writes:

>do any semiconductor makers have available on CD-ROM their databooks and
>application notes?

Great idea. Me too. My stock of dead trees is pretty out of date also.

-- 
-----------------------------------------------------------|"Nothing travels   |
| Dominic Herity,  dherity@cs.tcd.ie,                      |faster than light, |
|Computer Science Dept, Trinity College, Dublin 2, Ireland.|except possibly bad|
| Tel : +353-1-6772941 ext 1720 Fax : +353-1-6772204       |news"-Douglas Adams|
From: gerald.belton@ozonehole.new-orleans.la.us (Gerald Belton) 
Newsgroups: sci.electronics
Subject: Battery Gell cell or Lead
Date: 6 Jan 93 10:48:00 GMT
Distribution: world
Organization: The Ozone Hole - SKYDIVE New Orleans! - (504)891-3142 16,800 bps
Reply-To: gerald.belton@ozonehole.new-orleans.la.us (Gerald Belton) 

>I am in the process of making a rechargeable bicycle light and wanted to kno
>which type of battery would be better Gell Cell or a Lead Acid. What are the
>pros and cons of each? I have heard that it's not a good idea to fully
>discharge a Lead Acid is this true?  Also how would the cold effect each of
>these types of batteries?

They are essentially the same, except that a gell cell has the
electrolyte in a, well, "gelled" form instead of liquid.

You definitely do NOT want to be carrying a liquid-electrolyte lead-acid
battery around on a bicycle.  If you fall, you will have enough to worry
about without getting battery acid on yourself and your bike.

---
 . SLMR 2.1 . Death is God's Way of Dropping Carrier on You.
                                        
----
+======================================================================+
| The Ozone Hole - SKYDIVE New Orleans! - (504) 891-3142 HST/DS 16,800 |
| 3 Nodes <> USA Today <> Boardwatch Online <> 5.2 Gigs <> 73900 Files |
+======================================================================+
From: babb@sciences.sdsu.edu (J. Babb)
Newsgroups: sci.electronics
Subject: 8087 coprocessor prices
Date: 8 Jan 93 20:04:14 GMT
Followup-To: sci.electronics
Organization: SDSU - LARC
NNTP-Posting-Host: larc.sdsu.edu

How come 8087 prices are still up there?  Many times I've seen 80287
co-processors for less than  8087s in the same catalog. Having an old XT,
I can't justify paying $100 or $60, maybe, MAYBE $15. (I have a PD
astronomy program that'll run faster, thats all).
Jeff.  
Newsgroups: sci.electronics
From: doug@ve7frg.ampr.org (Doug Collinge - VE7GNU)
Subject: Re: Tube Amplifier Design Questions
Organization: G.M. Systems
Date: Thu, 7 Jan 1993 04:49:19 GMT
X-Newsreader: TIN [version 1.1 PL6]

How about a "class D" audio amplifier using tranmitting tubes?

Kind of defeats the purpose of using tubes at all but it's a
nice concept, something to start up a hifi company with...

Cheers!
Newsgroups: sci.electronics
From: luke@cs.city.ac.uk (Luke Whitaker)
Subject: question about AF signal transformers
Organization: City University
Date:  7 Jan 93 17:07:55 GMT

I had an idea to design and build an FET small signal amplifier based on 
a class B transformer coupled valve amp design, basically to see what 
an electric guitar would sound like through it.

However, in the electronics catalogues I have available (and a couple of 
shops I tried),  it appears that small audio frequency (AF) matching 
transformers are not readily available.  

Is this the case ? Is there any technical reason why small signal AF
transformers are a problem - I don't understand transformer technology very
well. The small transformers that are available seem to have frequency
responses way above audio. I saw some post here about why HF transformers can
be smaller than AF transformers, although the original post has expired on this
site. Does this imply that AF transformers *are* readily available, albiet 
physically large ?

Thanks in advance,

Luke

Xref: sparky sci.electronics:22113 rec.games.programmer:5290
From: det@phlan.sw.stratus.com (David Toland)
Newsgroups: sci.electronics,rec.games.programmer
Subject: Re: Sort of a Joke - sad though...
Date: 6 Jan 1993 18:07:35 GMT
Organization: Stratus Computer, Software Engineering
Distribution: na
NNTP-Posting-Host: phlan.sw.stratus.com

In article <1if650INNt9a@hp-col.col.hp.com> cab@col.hp.com (Chris Best) writes:
[someone else writes, no attribution given]:
>> If I remember, the Nintendo manual say that you should not connect
>> the game to projection TVs. Anyone know why? 
>Just a guess, since I know little of Nintendo (and I like
>it this way) - if they offer a device that senses screen
>position when you aim it at the TV (like a pistol, or isn't 
>there some sort of shoulder-held bazooka now?), it probably
>won't (or won't) work properly.  
>
>To answer what you MIGHT be asking, it won't hurt the TV.

Bzzzt.  Sorry, that is incorrect.  It *will* harm the TV.  Projection TV
systems are particularly sensitive to CRT "burn", a desensitization of
the phosphors from prolonged firing.  Video games often have fixed layouts
in high contrast and strong color, so after a few hours of playing your
favorite game you may find a ghost of it is permanently a part of
everything you watch on that TV.

By the way, the gun (which reads the "flying spot" of the video trace
from the screen), should work adequately with projection TV, so that is
*not* the problem.


-- 
--------------------------------------------------------------------------
All opinions are MINE MINE MINE, and not necessarily anyone else's.
det@phlan.sw.stratus.com   |  "Laddie, you'll be needin' something to wash
                           |  that doon with."
From: wellison@kuhub.cc.ukans.edu
Newsgroups: sci.electronics
Subject: re: Ancient Scope Info Required
Date: 5 Jan 93 12:36:01 CST
Organization: University of Kansas Academic Computing Services


>I am looking for _ANY_ info on the care and feeding of the old Tektronix
>scopes. I recently aquired a 20 MHz dual trace storage scope, but the
>calibration is miles out, and the switches need attention. The scope has
>plug-in timebase and amplifier modules as listed below.
>
>Oscilloscope		Type 564 
>
>Timebase		Type 2B67 \ Plug-in modules
>Dual trace amplifier	Type 3A72 / 
>
>If you can't provide info on these particular beasties, but have stuff on
>related modules / scopes, please contact me!
>
>These scopes were valve-based, and Tektronix no longer retain the manuals or
>provide any type of support for them. The scope has already allowed me to fix
>an ailing computer, so I won't let it go without a fight.
>
>Please post responses as follow-ups to this post, as I can't get E-mail.


A Tek 564 uh? Well your in luck as I too own such a 'beast' (along with the
2B67 and 3A72 plug-ins as well as the 3L5 1Hz to 1MHz spectrum analyiser and
3B3 delayed sweep and 3T77 random sweep plugins.) I just happen to have the
manuals for all of it too. The calibration of it is pretty straight forward
with the manual, but without it, you would have better luck trying to launch it
to Mars ;-) At any rate, I'll see if I can dig up some copies for you. BTW,
don't leave the secondary intensity turned up to high in storage mode or the
CRT will bite the big one (I.E. a perment trace in both the upper and lower
display areas). Nice little beasty though ;-)

-=-= Wes =-=-
Newsgroups: sci.electronics
From: cep4478@ultb.isc.rit.edu (C.E. Piggott )
Subject: Re: Replacement IR Remote Controls
Summary: gunk inside keyboard
Originator: cep4478@ultb
Organization: Rochester Institute of Technology
Date: Mon, 4 Jan 1993 18:06:03 GMT

Every once in a while, I take apart a remote control and find that the
PC board that makes up the keyboard is covered in a yellow, sticky gunk.
I assume this is supposed to be there, to improve the conductivity of the
rubber keyboard's feet.  Does anybody know what this stuff is?

Chris
-- 
Christopher E. Piggott, WZ2B                    cep4478@ultb.isc.rit.edu
President                                       wz2b.ampr [44.69.0.1]
Rochester Institute of Technology               wz2b @ WB2PSI.#WNY.NY.USA.NA
Amateur Radio Club K2GXT                        CEP4478@RITVAXA.BITNET
Newsgroups: sci.electronics,misc.legal
From: pmw2c@csissun10.ee.Virginia.EDU (Paul Michael Wayner)
Subject: Re: Recommend a book on "Patenting Your Invention"?
Reply-To: pmw2c@csissun10.ee.Virginia.EDU (Paul Michael Wayner)
Organization: University of Virginia
Date: Mon, 11 Jan 1993 23:35:20 GMT

In article <1993Jan11.214029.235@megatek.com>, cjp@megatek.com (Chris
"Systems Stud" Pikus) writes:
|> > kehoe@netcom.com (Thomas David Kehoe) writes:
|> > 
|> > >Would someone recommend a book about "How To Patent Your 
|> > >Invention"?  There must be several available.
|> 
|> 
|>  
|> bhayden@teal.csn.org (Bruce Hayden) writes:
|> > If you are an attorney, and want to advise someone else, 
|> > instead of writing a patent yourself, I would suggest one
|> > of the patent bar sets of books. I used Kayton, and it is
|> > very good. By the time you get done, you know what you need
|> > to at least know when you are getting in trouble.

One thing that I would suggest is that you may want to consult
a patent attorney about writing the claims for your patent
application.  If the claims are written improperly you will 
either get rejected in your application, or you will end up
with a patent that is worthless.  I used to be a patent examiner
and most of the people who filed there own applications tended
to have poorly written claims.

						Paul Wayner
Newsgroups: sci.electronics
From: Mike Diack <mike-d@staff.tc.umn.edu>
Subject: hunters & collectors
X-Xxdate: Sat, 9 Jan 93 17:13:53 GMT
Organization: persian cat & carpet co.
X-Useragent: Nuntius v1.1.1d7
Date: Sat, 9 Jan 1993 04:06:11 GMT

Where i come from (an insignificant pair of islands off the coast of
Antarctica), i managed to equip quite a reasonable workshop largely
by haunting auctions, clearance sales etc. I now find myself in the
(bloody cold bit of) USA, and perusing things like the auction column
of the Sunday paper reveals...Sod All...(other than dozens of antique
auctions - boring), now given that there is probably more high tech
going on in a 1 mile radius of where i am than ther was in the whole
of NZ, WHAT HAPPENS TO ALL THE LEFTOVERS ?. I've heard of gov't
auctions, but how does one find out about them ? What about 3M?
Honeywell?IBM?CDC? the list could go on and on. Any enlightenment
would be welcome
cheers
	Mike.
From: Tony.Duell@launchpad.unc.edu (Tony Duell)
Newsgroups: sci.electronics
Subject: Re: VCR video head removal
Date: 5 Jan 93 19:09:22 GMT
Organization: University of North Carolina Extended Bulletin Board Service

To remove 99% of VHS video heads (Betamax are much more difficult,
especially in aligning the new head), do this
1) disconnect the wiring on top of the head drum. This may be a series of
flexible wires (yellow, red, brown are the usual colours I think), or a
PCB. If it's wiring, just unsolder the wires going down near the spindle.
On a PCB type head, unsolder all the marked connections (look at the new
head to see which ones are not connected. On a few machines (NordMende  (I
think JVC deck mechanics)), you unsolder everything and them lift off the PCB
2) Remove the 2 screws on top of the drum near the spindle
3) pull off  the drum. if it won't move, either bollow a video head
puller, or gentle warm the drum e.g. with a hair dryer.
4) put the new head, right way round (match up any white marks on head and
spindle) on the machien
5) screw it down
6) solder the connections back
DO not apply any force to the pins coming out of the loer drum that go
through the PCB on the head. Make sure they are all free before removing
the head. Solder them back after screwing the head down. You can easily
damage the rotary transformer in the lower drum, and a new lower drum for
a high-end machine can cost #250.00 (about $400).
-tony 'PDP11 Hacker' Duell
ard@siva.bris.ac.uk

--
   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
Newsgroups: sci.electronics