Digest for sci.electronics.repair@googlegroups.com - 11 updates in 5 topics

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bleachbot <bleachbot@httrack.com>: Nov 17 05:06PM +0100

Tom Wilson <TomWilson@is.invalid>: Nov 22 03:03AM

On Mon, 10 Nov 2014 06:06:01 +0000, Tom Wilson wrote:
 
> But what's a good wire that will be ROUND?
 
Reporting back, and thanks for your help.
 
Here's her project, where a single tomoto wire cage
was turned into the standing and hanging (either way)
model of the silicon atom.
http://i61.tinypic.com/29w626w.jpg
 
Protons are the walnuts.
Neutrons are the chestnuts.
And pumpkin seeds (much smaller than acorns) are electrons.
http://i62.tinypic.com/314s5yg.jpg
 
The first energy level (1s2 orbital) is further from the second
energy level (2s2,2p6 orbitals) which itself is closest to the
third energy level (3s2,3p4 orbitals).
 
The other kids' projects are shown here, where most didn't
even try to create round loops which are 3D in shape.
http://i61.tinypic.com/1234ltl.jpg
http://i62.tinypic.com/30vhu76.jpg
http://i57.tinypic.com/2ptbg2d.jpg
"83LowRider" <83lowrider@nywilldo.com>: Nov 22 03:31AM -0500

> Neutrons are the chestnuts.
> And pumpkin seeds (much smaller than acorns) are electrons.
> http://i62.tinypic.com/314s5yg.jpg
 
Excellent!
Phil Allison <pallison49@gmail.com>: Nov 21 09:03PM -0800


> On a forum, I read this :
 
> "I am the proud new owner of a 2270. It seems to be in pretty good shape, but I noticed today that it seems like all the radio stations at once are coming from the left channel. The volume knob doesn't affect it, as it is the same level no matter where you turn it to. Changing the input selector doesn't help, and neither does moving the tuner. What is going on? "
 
 
** The fact it is only one channel and no controls have any effect indicates RF signals are entering one of the power amplifies via the speaker lead - probably travelling up the feedback loop into the input differential pair and being rectified / demodulated
 
Simple test, does it still happen with no speaker leads connected to the amp while listening via headphones ?
 
The earth on each speaker output terminal should have a 100nF ( film or ceramic ) cap to the nearest chassis point plus the output zobel may be faulty.
 
The same channel may also be suffering from parasitic oscillations at a few MHz - which only a scope would reveal.

 
 
... Phil
 
 
 
 
 
 
 
jurb6006@gmail.com: Nov 21 10:23PM -0800

>"Simple test, does it still happen with no speaker leads connected to the amp >while listening via headphones ?"
 
AHA. I shall ask.
"Arfa Daily" <arfa.daily@ntlworld.com>: Nov 22 02:14AM

"josephkk" <joseph_barrett@sbcglobal.net> wrote in message
news:tpdt6a1gotjmitoef2mjminch6nogm1cdd@4ax.com...
 
> Believable. I wonder if the crystal itself died. Might check that
> failure mode out if you are interested.
 
> ?-)
 
I did consider the xtal itself being at fault, but as Fender were sending a
new board out to us, I couldn't be bothered at the time to check. I still
have the board, so might stick some power on it and see if I can prove
anything.
 
Arfa
Amanda Riphnykhazova <licensedtoquill@gmail.com>: Nov 21 09:30AM -0800

I have always doubted vinegar as a bit of an old wives tale but after a few hours, it seems to have done something. I put the portafiler on it and turned on and it strangulated, wheezed, suddenly spat and then started pouring slightly dirty looking water out of (one side of the portafilter at) the bottom.
 
Either it works now or I may have to try citric acid a few times to clear whatever else is in there? It is being used in an ultra-hard water area and it has never been cleaned since I got it second hand in rural France
"William Sommerwerck" <grizzledgeezer@comcast.net>: Nov 21 09:58AM -0800

"Amanda Riphnykhazova" wrote in message
news:3af2ec99-7e56-4ba3-92f9-7eb585a2e615@googlegroups.com...
 
> It is being used in an ultra-hard water area and it has never
> been cleaned since I got it second hand in rural France.
 
There are products (such as CLR) which are designed to remove hard-water
deposits.
 
http://www.homedepot.com/p/CLR-28-oz-Calcium-Lime-and-Rust-Remover-CL12/100670289
 
Whether they will clean your espesso machine without damaging metal parts, I
don't know. Some reviewers state that CLR leaves a residual taste on metal
objects that will not come off.
Amanda Riphnykhazova <licensedtoquill@gmail.com>: Nov 21 10:32AM -0800

Yes, I had heard that you can irretrievably adulterate a coffee machine such that it can never be used for coffee any more if you put CLR in it. (But it definitely burns off all the limescale in minutes)
 
No one seems to have come across a CLR alternative (of which there are MANY) which doesn't do this.
dplatt@coop.radagast.org (David Platt): Nov 21 11:37AM -0800

>Yes, I had heard that you can irretrievably adulterate a coffee machine
>such that it can never be used for coffee any more if you put CLR in it.
>(But it definitely burns off all the limescale in minutes)
 
The active ingredients seem to be lactic and gluconic acids (to
dissolve the mineral deposits), and lauramine oxide (a surfactant).
 
I wonder whether the residual taste from the CLR is due to CLR
residue, or whether the CLR attacks and alters the surface of the
metal enough to cause it to start "leaking" metal ions into the
water. The latter could lead to a pretty nasty taste, and subsequent
cleaning of the coffeemaker wouldn't help.
 
>No one seems to have come across a CLR alternative (of which there are
>MANY) which doesn't do this.
 
For filters and other reasonably small, removable elements, I wonder
whether putting them into an ultrasonic cleaner, with water and a
small amount of a neutral surfactant, might not do the trick. This
might remove the mineral scale buildup through an essentially
mechanical process, rather than a chemical one, and wouldn't attack
the surface of the metal with chemicals that could alter its surface
chemistry and cause it to "leak" ions.
"Arfa Daily" <arfa.daily@ntlworld.com>: Nov 22 02:10AM

"David Platt" <dplatt@coop.radagast.org> wrote in message
news:tsg4kb-jf2.ln1@coop.radagast.org...
> mechanical process, rather than a chemical one, and wouldn't attack
> the surface of the metal with chemicals that could alter its surface
> chemistry and cause it to "leak" ions.
 
My son-in-law used to work for a commercial coffee machine place, and they
used a powerful limescale remover that fetched everything back to factory
original. I'll ask him if he can remember what it was. For general cleaning,
there are proper water-path washing agents that you can run through
machines. The one I have is Suma Caffe from Johnson Diversy, but cheap it
ain't ...
 
Arfa
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