sci.electronics.repair@googlegroups.com

Today's topics:

* Electronic curiosities - 3 messages, 3 authors
http://groups.google.com/group/sci.electronics.repair/t/92fb1a53d8547e80?hl=en
* Sanyo TV - 1 messages, 1 author
http://groups.google.com/group/sci.electronics.repair/t/9e4c8f5b72f9e8d7?hl=en
* Philips PM5131 Manual - 2 messages, 2 authors
http://groups.google.com/group/sci.electronics.repair/t/0408aa402bb47498?hl=en
* Digital Volume Controls - 1 messages, 1 author
http://groups.google.com/group/sci.electronics.repair/t/215bd1b40b7247b6?hl=en
* TV picture distorted - 3 messages, 3 authors
http://groups.google.com/group/sci.electronics.repair/t/ec61658f4376abe1?hl=en
* OT--Actual electronics repair question - 1 messages, 1 author
http://groups.google.com/group/sci.electronics.repair/t/1c7563aead5e20a6?hl=en
* Walkman Speakers - 1 messages, 1 author
http://groups.google.com/group/sci.electronics.repair/t/6948823fdf40b407?hl=en
* What kind of picture on a picture tube - 2 messages, 2 authors
http://groups.google.com/group/sci.electronics.repair/t/3d2d2d9a6d59b940?hl=en

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TOPIC: Electronic curiosities
http://groups.google.com/group/sci.electronics.repair/t/92fb1a53d8547e80?hl=en
==============================================================================

== 1 of 3 ==
Date: Sun, Jan 16 2011 3:51 pm
From: Adrian C

On 16/01/2011 21:58, David Nebenzahl wrote:

> Of course math is essential to understanding electronics. I'm OK with
> algebra and trig, but have problems with calculus, even though I have a
> basic understanding of it (differentiation, integration, etc.).
>
> Maybe in the next lifetime ...
>

Nah, plenty to read in this one :)

I wonder if you are aware of this collection of US Navy training
manuals. Looks pretty well written, and only written 13 years ago so
relatively recent.

http://www.rarmy.com/coleman/neets/index.html

--
Adrian C

== 2 of 3 ==
Date: Sun, Jan 16 2011 6:12 pm
From: David Nebenzahl

On 1/16/2011 3:14 PM William Sommerwerck spake thus:

[I wrote, which for some reason William failed to attribute:]

>> Of course math is essential to understanding electronics.
>> I'm OK with algebra and trig, but have problems with calculus,
>> even though I have a basic understanding of it (differentiation,
>> integration, etc).
>
> Calculus is pretty simple -- if you have a good book. I can't recommend any,
> because I don't know any off the top of my head. (Recommendations, anyone?)
>
> I took calculus in high school 45 years ago, at a time when very, very few
> high schools in the US offered it. We were given a book to study over the
> summer, which carefully walked the reader through the basics of the
> differential calculus. When we got to class in the fall, we a preliminary
> understanding under our belts.

I took one semester of calculus back in college and still have the
textbook, a giant tome that's pretty good: /Calculus and Analytic
Geometry/, Edwards and Penney. Didn't do too badly in the course, but
that was a while ago ...

> You also need to learn about Laplace transforms. They make it possible to
> analyze circuits with simple algebra, rather than differential equations.
> Very, very handy.

No doubt. Wouldn't hurt to know Fourier analysis either, and I'm sure a
bunch of other techniques.

--
Comment on quaint Usenet customs, from Usenet:

To me, the *plonk...* reminds me of the old man at the public hearing
who stands to make his point, then removes his hearing aid as a sign
that he is not going to hear any rebuttals.

== 3 of 3 ==
Date: Sun, Jan 16 2011 9:03 pm
From: Tony Matt

On 1/15/2011 10:47 PM, David Nebenzahl wrote:
> Trying to teach myself electronics, I've been reading a few textbooks I
> inherited on the subject. Tough going, as my math is in serious need of
> repair.
>
> Anyhow, found a couple of interesting things in these older books:
>
> 1. TRF:
>
> In the section on modulation, demodulation and other radio-related stuff
> one book brings up "the tuned radio-frequency receiver" before
> discussing superhet, as one would expect. But they say;
>
> During the evolution of radio, the tuned-radio-frequency (TRF)
> receiver was used to receive AM signals. Today, a few special
> applications still use TRF receivers.
>
> Now, they go on to explain why TRF is inferior to superheterodyne. But
> I'm curious: are there still any radios that use TRF? and why? (Keep in
> mind this book was written in 1979).

The Realistic TRF (12-655) radio was sold into the (IIRC) mid-80s:
http://www.radiomuseum.org/r/radio_shac_realistic_long_range_trf.html
This link indicates that it was actually a superhet with an RF stage; I
was under the impression all these years that it was a solid state
analog to an AK-40 or similar. Oh well.

TM

==============================================================================
TOPIC: Sanyo TV
http://groups.google.com/group/sci.electronics.repair/t/9e4c8f5b72f9e8d7?hl=en
==============================================================================

== 1 of 1 ==
Date: Sun, Jan 16 2011 3:57 pm
From: "Vince Schmitt"

Hi!
What can you do with a Sanyo MDL HDTV? The left side light is out and I
replaced the Master backlight converter and it still doesn't light up, I can
shake the set a little and it will come on momentarily. It acts like the
problem is inside the screen. Any ideas?
Thank you.
Vince

==============================================================================
TOPIC: Philips PM5131 Manual
http://groups.google.com/group/sci.electronics.repair/t/0408aa402bb47498?hl=en
==============================================================================

== 1 of 2 ==
Date: Sun, Jan 16 2011 5:45 pm
From: "Dave M"

Archon wrote:
> Hi, Anyone out there got a good copy of page 41 of this manual
> (Calibration table)
>
> The PM5131 Function Gen manual is available from hundreds of download
> sites free and pay, all have the same copy with page 41 doubled over.
>
> All I need is page 41....anyone? Will pay!!
>
> Remove _SpamNO to email me direct
>
> TIA JC

I have a PDF of the complete manual. Looks like page 41 is intact. The
file is secured (unable to extract the page). OK to send the entire manual
(it's only 3Mb)?
Send a good email address if you want me to send.

--
David
dgminala at mediacombb dot net

== 2 of 2 ==
Date: Sun, Jan 16 2011 8:30 pm
From: Archon

On 1/16/2011 8:45 PM, Dave M wrote:
> Archon wrote:
>> Hi, Anyone out there got a good copy of page 41 of this manual
>> (Calibration table)
>>
>> The PM5131 Function Gen manual is available from hundreds of download
>> sites free and pay, all have the same copy with page 41 doubled over.
>>
>> All I need is page 41....anyone? Will pay!!
>>
>> Remove _SpamNO to email me direct
>>
>> TIA JC
>
> I have a PDF of the complete manual. Looks like page 41 is intact. The
> file is secured (unable to extract the page). OK to send the entire manual
> (it's only 3Mb)?
> Send a good email address if you want me to send.
>
Hi David, Is page 41 a large table? or just a single page with the
column to the right of "frequency" overlapped and illegible?

JC

==============================================================================
TOPIC: Digital Volume Controls
http://groups.google.com/group/sci.electronics.repair/t/215bd1b40b7247b6?hl=en
==============================================================================

== 1 of 1 ==
Date: Sun, Jan 16 2011 7:39 am
From: "Arfa Daily"

"William Brown" <wbrown@yahoo.com> wrote in message
news:vjk4j61b33us57aru9ivmjuts3e8nq4jcf@4ax.com...
>
>
> I was told to totally remove the grease as this has leaked out from the
> spindle, but not my theory.
>
>
> So is it OK for the contacts to run dry or should they be lubricated
> with CRC 2.26 or ELECTROLUBE EML.
>
>
> Thanks

It is very common for the 'stirring treacle' grease to migrate down the
spindle and onto the Gray disc and contacts in these rotary encoders, as
used as the volume control on many cheapo hifi units. I have restored more
of these than I care to remember over the years, by completely removing all
the grease from the disc and contacts. Before reassembling, I always add
just a little good quality (Electrolube in my case) contact cleaner /
lubricant, although strictly speaking, this should not be necessary, as both
the disc and the fixed contacts are usually gold plated. The success rate
and long-term refailure rate are excellent if you do a decent job, and it
doesn't take long.

Arfa

==============================================================================
TOPIC: TV picture distorted
http://groups.google.com/group/sci.electronics.repair/t/ec61658f4376abe1?hl=en
==============================================================================

== 1 of 3 ==
Date: Sun, Jan 16 2011 6:11 pm
From: "PE"

Hi all: My 15-yr old Toshiba 27" crt television has recently developed a
problem which is that approx 15 minutes after being turned on, the picture
bows inward on the left and right sides. Then, after a few more minutes,
the picture resolves and returns to normal and remains perfect for the
remaining time the tv is on. If the symptom described above means the crt
is wearing out, so be it, the set will soon be history. However, I'm
wondering whether some other, replaceable part, might be going bad and
causing the temporarily distorted picture.

Would appreciate any suggestions re. probable cause(s) of symptom described
above. Am basically novice, but handy and with soldering skills, and have
done a few simple tv repairs in the past. Thanks for your replies!

== 2 of 3 ==
Date: Sun, Jan 16 2011 6:31 pm
From: "Phil Allison"

"PE"

> Hi all: My 15-yr old Toshiba 27" crt television has recently developed a
> problem which is that approx 15 minutes after being turned on, the picture
> bows inward on the left and right sides. Then, after a few more minutes,
> the picture resolves and returns to normal and remains perfect for the
> remaining time the tv is on. If the symptom described above means the crt
> is wearing out, so be it, the set will soon be history. However, I'm
> wondering whether some other, replaceable part, might be going bad and
> causing the temporarily distorted picture.
>
> Would appreciate any suggestions re. probable cause(s) of symptom
> described above. Am basically novice, but handy and with soldering
> skills, and have done a few simple tv repairs in the past.

** The symptoms suggest a cracked solder joint that is expanding as the temp
rises.

But you failed to mention how quickly the symptom arrives and leaves - so
it is not clear if my scenario applies.

.... Phil

== 3 of 3 ==
Date: Sun, Jan 16 2011 11:10 pm
From: "``ZACK``"

"PE" <ple@ix.netcom.com> wrote in message
news:_PednQsdJv8fOK7QnZ2dnUVZ_tOdnZ2d@earthlink.com...
> Hi all: My 15-yr old Toshiba 27" crt television has recently developed a
> problem which is that approx 15 minutes after being turned on, the picture
> bows inward on the left and right sides. Then, after a few more minutes,
> the picture resolves and returns to normal and remains perfect for the
> remaining time the tv is on. If the symptom described above means the crt
> is wearing out, so be it, the set will soon be history. However, I'm
> wondering whether some other, replaceable part, might be going bad and
> causing the temporarily distorted picture.
>
> Would appreciate any suggestions re. probable cause(s) of symptom
> described above. Am basically novice, but handy and with soldering
> skills, and have done a few simple tv repairs in the past. Thanks for
> your replies!
horizontal coupling cap
faulty yoke
or flyback tranformer circuit
pincushion transformer circuit
or try here
http://www.devileye.net/catalog/boiling_liquefied_gas/side_pincushion_correction_modulator_circuit.html

or
http://www.google.com.au/search?hl=en&client=firefox-a&hs=bCP&rls=org.mozilla:en-US:official&channel=s&&sa=X&ei=0ugzTaTRA4K6vwPtzYmpCw&ved=0CBkQvwUoAQ&q=pincushion+transformer+circuit&spell=1

==============================================================================
TOPIC: OT--Actual electronics repair question
http://groups.google.com/group/sci.electronics.repair/t/1c7563aead5e20a6?hl=en
==============================================================================

== 1 of 1 ==
Date: Sun, Jan 16 2011 6:13 pm
From: Jeff Liebermann

On Sun, 16 Jan 2011 16:38:37 -0500, "Michael A. Terrell"
<mike.terrell@earthlink.net> wrote:

>> > RG-174?
>>
>> Could have been. About the right diameter.
>
> I have a 1000 foot spool under my main workbench to make custom
>probes with.

I prefer LMR100, RG316, or RG188. Most of the pigtails I've bought
use RG-316. I don't have a 1000ft roll but do have a tangled mess of
indeterminant length buried under the bench.

--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

==============================================================================
TOPIC: Walkman Speakers
http://groups.google.com/group/sci.electronics.repair/t/6948823fdf40b407?hl=en
==============================================================================

== 1 of 1 ==
Date: Sun, Jan 16 2011 9:30 pm
From: vjp2.at@at.BioStrategist.dot.dot.com

- = -
Vasos Panagiotopoulos, Columbia'81+, Reagan, Mozart, Pindus, BioStrategist
http://www.panix.com/~vjp2/vasos.htm http://www.facebook.com/vasjpan2
---{Nothing herein constitutes advice. Everything fully disclaimed.}---
[Homeland Security means private firearms not lazy obstructive guards]
[Urb sprawl confounds terror] [Phooey on GUI: Windows for subprime Bimbos]

==============================================================================
TOPIC: What kind of picture on a picture tube
http://groups.google.com/group/sci.electronics.repair/t/3d2d2d9a6d59b940?hl=en
==============================================================================

== 1 of 2 ==
Date: Mon, Jan 17 2011 12:10 am
From: HubertHumpfree@dazed.com

I've always wondered what kind of a picture they put on picture tubes?
Is it scenery, or family photos, or porn?

Hubert Hump Free
CEO Forever Smiles Inc.

== 2 of 2 ==
Date: Mon, Jan 17 2011 12:33 am
From: David Nebenzahl

On 1/17/2011 12:10 AM HubertHumpfree@dazed.com spake thus:

> I've always wondered what kind of a picture they put on picture tubes?
> Is it scenery, or family photos, or porn?
>
> Hubert Hump Free
> CEO Forever Smiles Inc.

Sorry, pal, you're not even up to Jack Handey level. Keep trying, though.

--
Comment on quaint Usenet customs, from Usenet:

To me, the *plonk...* reminds me of the old man at the public hearing
who stands to make his point, then removes his hearing aid as a sign
that he is not going to hear any rebuttals.

==============================================================================

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