sci.electronics.repair@googlegroups.com

Today's topics:

* del1702fp monitor - 2 messages, 2 authors
http://groups.google.com/group/sci.electronics.repair/t/e9a933a2bf378485?hl=en
* Weird stuff -- update -- (was Electronic Kenmore refrigerator not working,
what does this sign mean) - 8 messages, 6 authors
http://groups.google.com/group/sci.electronics.repair/t/90e33648f2879de5?hl=en
* Supergluing your fingers together - 10 messages, 8 authors
http://groups.google.com/group/sci.electronics.repair/t/27d3b5cbe57935fb?hl=en
* Yet another bulging-capacitors replacement - 3 messages, 3 authors
http://groups.google.com/group/sci.electronics.repair/t/3ec97de65fce9bb3?hl=en
* Why we have Gravity - 1 messages, 1 author
http://groups.google.com/group/sci.electronics.repair/t/004d04dfe74c9553?hl=en
* Technics KN800 MIDI keyboard no sound - 1 messages, 1 author
http://groups.google.com/group/sci.electronics.repair/t/f95dad92d98851fc?hl=en

==============================================================================
TOPIC: del1702fp monitor
http://groups.google.com/group/sci.electronics.repair/t/e9a933a2bf378485?hl=en
==============================================================================

== 1 of 2 ==
Date: Thurs, Sep 2 2010 5:32 pm
From: Jeff Liebermann

On Thu, 2 Sep 2010 16:51:30 -0700 (PDT), ajd15 <ajdean15@gmail.com>
wrote:

>I have a 1702fp monitor that died. The power light is on but the
>screen is blank. I need a manual or some sugestions on a repair
>approach.

Sounds familiar. Blown electrolytic capacitors. Find and replace:
<http://ccl-la.com/LCDrepair12.htm>
<http://www.instructables.com/id/FREE-17%22-LCD-Monitor---How-to-do-it%3F/>
When you look for replacement caps (i.e. eBay, Digikey, Mouser, etc),
be sure to get 105C low-ESR caps.

PS... reading the manual is a sign of weakness, inexperience, and
desperation. You probably don't need a manual for this repair.
--
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

== 2 of 2 ==
Date: Thurs, Sep 2 2010 7:36 pm
From: "John Keiser"

If not the caps, the transistors that drive the inverters are also a known
issue. Kits available on eBay for about $5 delivered [via Hong Kong].
If you don't see a bulge, an ESR meter will test the caps [mine were all
good], leading me to discover the 2 shorted transistors. Now fine.

"ajd15" <ajdean15@gmail.com> wrote in message
news:593044d6-12fa-4b7f-9609-33b7602835c1@l20g2000yqe.googlegroups.com...
>I have a 1702fp monitor that died. The power light is on but the
> screen is blank. I need a manual or some sugestions on a repair
> approach.
>
> Thanks
> Tony

==============================================================================
TOPIC: Weird stuff -- update -- (was Electronic Kenmore refrigerator not
working, what does this sign mean)
http://groups.google.com/group/sci.electronics.repair/t/90e33648f2879de5?hl=en
==============================================================================

== 1 of 8 ==
Date: Thurs, Sep 2 2010 5:43 pm
From: "Dave M"

Ignoramus28169 wrote:
> Things are getting weirder and weirder. My original post is at the
> bottom.
>
> I have received the replacement relay and capacitor today.
>
> Installed them (it was a 2 minute job).
>
> Plugged in the fridge.
>
> The compressor happily started working normally, mildly vibrating and
> indicating in all respects that it is running fine.
>
> Happy after 2 minutes, I turned off the fridge, and reinstalled the
> rear insulated covering panel and ground.
>
> Plugged in again and I HEARD THE SAME OLD DREADED BUZZING SOUND. Now,
> the compressor motor would not start again! It busses fomr several
> seconds and the relay clicks and turns it off.
>
> I am completely puzzled as to why exactly it turned on once, but would
> not turn on again.
>
> Any idea?
>
> i
>
>
> On 2010-08-31, Ignoramus20906 <ignoramus20906@NOSPAM.20906.invalid>
> wrote:
>> I have an electronic Kenmore refrigerator 596.50013100. I bought it
>> from a private party over a year ago and it has been working great
>> until now. It seems very well made, overall.
>>
>> Yesterday it started beeping and displaying a strange trouble signal:
>>
>> http://igor.chudov.com/tmp/Kenmore-Trouble.jpg
>>
>> It is right above the word "Kenmore", is red and looks like a crossed
>> lock and an exclamation.
>>
>> The temperature in the unit has been rising since then and clearly,
>> it is not cooling anything. Right now both freezer and fridge are at
>> 46 degrees F.
>>
>> I tried calling Kenmore, but could only speak to dummies who are
>> forbidden to give any diagnostics.
>>
>> My question is WTF does this sign mean? It is meant to tell me
>> something.
>>
>> Thanks
>>
>> i

The lit symbology indicates that the internal temperature doesn't agree with
the set point. From your description, I'd say that the compressor has an
internal problem (stuck valves, galled bearings, dessicant particles in the
compressor, etc). Most consumer grade refrigeration compressors aren't
servicable, meaning that you need to get your checkbook warmed up for a
sizeable deduction from your bank account.

That said, there are a couple things for you to do. First, remove the back
cover, leaving the ground wire unconnected, and see if it kicks off again.
If it continues to run, connect the ground wire to the chassis. If it kicks
off when you connect the ground wire, then you have to find out where the
ground fault is. Most likely, that will be inside the compressor. Don't use
it in this condition; it is a lethal weapon without the safety ground
connected.
If you have an AC clamp meter, measure the current on the hot wire going
into the compressor. It should kick up to 10A or so when the compressor
starts up, and quickly dropping down to its normal running current of a few
amps. If the current stays high after a few seconds, that means that it
isn't starting normally. The overcurrent relay tripping in a few seconds
indicate that fact. In any case, the compressor is highly suspect.

--
David
dgminala at mediacombb dot net

== 2 of 8 ==
Date: Thurs, Sep 2 2010 6:10 pm
From: Tim Wescott

On 09/02/2010 05:14 PM, rangerssuck wrote:
> No doubt someone mor knowledgable will have something to add here, but
> it sounds like the compressor is trying to start against a load. How
> long was it unplugged while you were replacing the cover? I imagine it
> should be unplugged at least three ininutes, and probably five.
> However, I'd also imagine that there would be a timer of some sort to
> prevent short-cycling. Of course, the thermal protection in the motor
> would kick in eventually, but my air conditioner, for example, simply
> will not run the compressor for a few minutes after you plug it in if
> it had been running just prior to unplugging.
>
> Anyway, I'd suggest that you let it rest a few minutes and then try
> again.

We had an older fridge that'd do this any time the power blinked -- and
we live out in the boonies. We learned to unplug it for a few minutes
and plug it back in.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" was written for you.
See details at http://www.wescottdesign.com/actfes/actfes.html

== 3 of 8 ==
Date: Thurs, Sep 2 2010 6:12 pm
From: Ignoramus28169

On 2010-09-03, Karl Townsend <karltownsend.NOT@embarqmail.com> wrote:
> ...
>>Happy after 2 minutes, I turned off the fridge, and reinstalled the
>>rear insulated covering panel and ground.
>>
>>Plugged in again and I HEARD THE SAME OLD DREADED BUZZING SOUND. Now,
>>the compressor motor would not start again! It busses fomr several
>>seconds and the relay clicks and turns it off.
>>
>>I am completely puzzled as to why exactly it turned on once, but would
>>not turn on again.
>>
>>Any idea?
>>
> Did you try cursing and kicking? That's my normal solution to this
> type problem. Its never helped, but I keep trying it anyway.
>

That is always my preferred approach. Sometimes it works.

i

== 4 of 8 ==
Date: Thurs, Sep 2 2010 6:12 pm
From: Ignoramus28169

On 2010-09-03, Ignoramus28169 <ignoramus28169@NOSPAM.28169.invalid> wrote:
> Things are getting weirder and weirder. My original post is at the bottom.
>
> I have received the replacement relay and capacitor today.
>
> Installed them (it was a 2 minute job).
>
> Plugged in the fridge.
>
> The compressor happily started working normally, mildly vibrating and
> indicating in all respects that it is running fine.
>
> Happy after 2 minutes, I turned off the fridge, and reinstalled the
> rear insulated covering panel and ground.
>
> Plugged in again and I HEARD THE SAME OLD DREADED BUZZING SOUND. Now,
> the compressor motor would not start again! It busses fomr several
> seconds and the relay clicks and turns it off.
>
> I am completely puzzled as to why exactly it turned on once, but would
> not turn on again.
>
> Any idea?

Oddly enough, after waiting for a while, it started fine and is
cooling down at an acceptable rate.

i

> i
>
>
> On 2010-08-31, Ignoramus20906 <ignoramus20906@NOSPAM.20906.invalid> wrote:
>> I have an electronic Kenmore refrigerator 596.50013100. I bought it
>> from a private party over a year ago and it has been working great
>> until now. It seems very well made, overall.
>>
>> Yesterday it started beeping and displaying a strange trouble signal:
>>
>> http://igor.chudov.com/tmp/Kenmore-Trouble.jpg
>>
>> It is right above the word "Kenmore", is red and looks like a crossed
>> lock and an exclamation.
>>
>> The temperature in the unit has been rising since then and clearly, it
>> is not cooling anything. Right now both freezer and fridge are at 46
>> degrees F.
>>
>> I tried calling Kenmore, but could only speak to dummies who are
>> forbidden to give any diagnostics.
>>
>> My question is WTF does this sign mean? It is meant to tell me
>> something.
>>
>> Thanks
>>
>> i

== 5 of 8 ==
Date: Thurs, Sep 2 2010 7:12 pm
From: "Bill"

>
> Oddly enough, after waiting for a while, it started fine and is
> cooling down at an acceptable rate.
>

Get a refrigerator thermometer (kitchen stuff department of stores), then
keep an eye on the temperature.

If there was a lot of water which came out from having it off while you
fixed it, and this happens again in a month or so, suspect the
defrost/heater/timer.

== 6 of 8 ==
Date: Thurs, Sep 2 2010 9:14 pm
From: "Geoffrey S. Mendelson"

Ignoramus28169 wrote:
> Oddly enough, after waiting for a while, it started fine and is
> cooling down at an acceptable rate.

As someone else said it won't start if it is under a load. It has to
rest before being plugged in again.

We have a little device that looks like a cheap surge protector that
will not turn on unless it has been off for four minutes.

Geoff.

--
Geoffrey S. Mendelson N3OWJ/4X1GM
To help restaurants, as part of the "stimulus package", everyone must order
dessert. As part of the socialized health plan, you are forbidden to eat it. :-)

== 7 of 8 ==
Date: Fri, Sep 3 2010 12:23 am
From: harry

On Sep 3, 1:14 am, rangerssuck <rangerss...@gmail.com> wrote:
> No doubt someone mor knowledgable will have something to add here, but
> it sounds like the compressor is trying to start against a load. How
> long was it unplugged while you were replacing the cover? I imagine it
> should be unplugged at least three ininutes, and probably five.
> However, I'd also imagine that there would be a timer of some sort to
> prevent short-cycling. Of course, the thermal protection in the motor
> would kick in eventually, but my air conditioner, for example, simply
> will not run the compressor for a few minutes after you plug it in if
> it had been running just prior to unplugging.
>
> Anyway, I'd suggest that you let it rest a few minutes and then try
> again.

The above is exactly right.

== 8 of 8 ==
Date: Fri, Sep 3 2010 12:26 am
From: harry

On Sep 3, 2:12 am, Ignoramus28169 <ignoramus28...@NOSPAM.
28169.invalid> wrote:
> On 2010-09-03, Ignoramus28169 <ignoramus28...@NOSPAM.28169.invalid> wrote:
>
>
>
>
>
> > Things are getting weirder and weirder. My original post is at the bottom.
>
> > I have received the replacement relay and capacitor today.
>
> > Installed them (it was a 2 minute job).
>
> > Plugged in the fridge.
>
> > The compressor happily started working normally, mildly vibrating and
> > indicating in all respects that it is running fine.
>
> > Happy after 2 minutes, I turned off the fridge, and reinstalled the
> > rear insulated covering panel and ground.
>
> > Plugged in again and I HEARD THE SAME OLD DREADED BUZZING SOUND. Now,
> > the compressor motor would not start again! It busses fomr several
> > seconds and the relay clicks and turns it off.  
>
> > I am completely puzzled as to why exactly it turned on once, but would
> > not turn on again.
>
> > Any idea?
>
> Oddly enough, after waiting for a while, it started fine and is
> cooling down at an acceptable rate.
>
> i
>
>
>
> > i
>
> > On 2010-08-31, Ignoramus20906 <ignoramus20...@NOSPAM.20906.invalid> wrote:
> >> I have an electronic Kenmore refrigerator 596.50013100. I bought it
> >> from a private party over a year ago and it has been working great
> >> until now. It seems very well made, overall.
>
> >> Yesterday it started beeping and displaying a strange trouble signal:
>
> >>          http://igor.chudov.com/tmp/Kenmore-Trouble.jpg
>
> >> It is right above the word "Kenmore", is red and looks like a crossed
> >> lock and an exclamation.
>
> >> The temperature in the unit has been rising since then and clearly, it
> >> is not cooling anything. Right now both freezer and fridge are at 46
> >> degrees F.
>
> >> I tried calling Kenmore, but could only speak to dummies who are
> >> forbidden to give any diagnostics.
>
> >> My question is WTF does this sign mean? It is meant to tell me
> >> something.
>
> >> Thanks
>
> >> i- Hide quoted text -
>
> - Show quoted text -- Hide quoted text -
>
> - Show quoted text -

Not odd at all. It can't start up against a load. You need to wait
for the gas pressures to equalise in the system. Then it starts up
against no-load.
It needs to be off for around five minutes before restarting.

==============================================================================
TOPIC: Supergluing your fingers together
http://groups.google.com/group/sci.electronics.repair/t/27d3b5cbe57935fb?hl=en
==============================================================================

== 1 of 10 ==
Date: Thurs, Sep 2 2010 5:49 pm
From: Jeff Liebermann

On Thu, 2 Sep 2010 18:52:31 +0000 (UTC), Meat Plow <mhywatt@yahoo.com>
wrote:

>Hmm I'll have to remember that. Didn't seem to prove very toxic to my
>cut. Skin had mended around 10 days after. I probably wouldn't use it
>if I cut my finger off though :)

When dried, it's non-toxic. In liquid form, the volatiles are a
problem if they get to the mucus membranes. Repeated use can also
cause one to develop an allergy, with flu-like symptoms:
<http://wapedia.mobi/en/Cyanoacrylates>
<http://wapedia.mobi/en/Cyanoacrylate#3.>
I've glued a few cuts together without much difficulty. It stung a
bit when applied, but that went away rapidly.

Hmmm.... looks like the common adhesive (methyl 2-cyanoacrylate or
ethyl-2-cyanoacrylate), is different from the veterinary glue (n-Butyl
cyanoacrylate), which is different from the surgical glue (2-octyl
cyanoacrylate).

--
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

== 2 of 10 ==
Date: Thurs, Sep 2 2010 6:00 pm
From: Jeff Liebermann

On Thu, 02 Sep 2010 18:37:13 -0500, AZ Nomad
<aznomad.3@PremoveOBthisOX.COM> wrote:

>Has anybody ever found an application where superglue works well
>except on human skin? I find the crap brittle as hell and have yet to
>see anything glued with it last more than a few weeks before breaking.

I have to agree on the brittleness problem. It's so handy, that I
tend use it on items where urethane, RTV, or epoxy would be more
appropriate.

Where I've used SuperGlue successfully are:
1. Custom rubber o-rings
2. Glass and ceramic repairs. I think my coffee cup has had the
handle superglued in 3 different places.
3. Hard plastic parts where the break is clean and has not been
stretched or bent. If the plastic is soft and/or bends, CA will not
work.
4. Tacking large parallel surfaces together.
5. Tacking SMD components to a PCB before soldering. A toothpick
works well as an applicator.

--
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

== 3 of 10 ==
Date: Thurs, Sep 2 2010 6:01 pm
From: Sjouke Burry

Meat Plow wrote:
> On Thu, 02 Sep 2010 18:37:13 -0500, AZ Nomad wrote:
>
>> On Thu, 2 Sep 2010 11:20:39 -0700, Dave Platt <dplatt@radagast.org>
>> wrote:
>>>> Surprising I've never done it before . Thumb and second finger firmly
>>>> glued to either side of a connecctor. I tried methylated spirits first
>>>> but no effect seemingly. Then dilute acetone as nail varnish remover. I
>>>> was concerned about being too long on the skin so some cotton wool
>>>> balls of acetone around both areas and a Q-tip soaked in acetone, with
>>>> a rotating wedge-like motion, cautiously wedging skin from connector
>>>> worked, but anyone elses experiences/advice for the next time?
>>> Keeping a bottle of superglue debonder around is a cheap investment. If
>>> you go to a hobby store which carries a selection of cyanoacrylate glues
>>> (usually of different viscosities and bonding speeds) you ought to find
>>> a supply of debonder in the same rack.
>>
>> Has anybody ever found an application where superglue works well except
>> on human skin? I find the crap brittle as hell and have yet to see
>> anything glued with it last more than a few weeks before breaking.
>
> Any application that does not apply a sheer force. I use it to glue new
> guitar frets into a slotted fretboard. It's a CA designed for that
> application though. Also good for guitar nuts. Can't imagine something so
> popular that didn't work.
>
>
>
I collect stones. When something breaks, superglue works very well.

== 4 of 10 ==
Date: Thurs, Sep 2 2010 6:30 pm
From: "William Sommerwerck"

> Any application that does not apply a sheer force.

When I worked at a hi-fi store, we used to super-glue tone-arm bases onto
the metal surface of the Lux turntable arm mount (rather than cutting screw
holes into the surface). This allowed the mount to be reused for a different
arm, simply by holding a block of wood against the tone-arm base and
striking it with a hammer.

== 5 of 10 ==
Date: Thurs, Sep 2 2010 6:20 pm
From: dplatt@radagast.org (Dave Platt)

In article <sih086pn68ccahqo9iddtrn5l7ee7d62gj@4ax.com>,
Jeff Liebermann <jeffl@cruzio.com> wrote:

>I have to agree on the brittleness problem. It's so handy, that I
>tend use it on items where urethane, RTV, or epoxy would be more
>appropriate.

Thee are some newer formulations on the market which are intended
to be less brittle, and thus able to handle more impact that the
standard formulas. The one I bought (Gorilla brand) says that it's
reinforced with rubber particles. I infer that the rubber both
reduces stress within the adhesive during compression or tension (thus
reducing the tendency for cracks to start) and also helps prevent
cracks from propagating through the material once they do start.

http://www.threebond.co.jp/en/technical/technicalnews/pdf/tech46.pdf
has some details.

I've made my first experimental use of the Gorilla rubber-
reinforced variety, gluing a set of hardwood scales to a pocketknife
handle. I'll be quite interested to see how the knife holds up with
time. I know I'm taking a risk, not fastening the scales to the
handle with small screws... but the scales are hand-finished olive
burl and I just couldn't bear to drill holes in it.

--
Dave Platt <dplatt@radagast.org> AE6EO
Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

== 6 of 10 ==
Date: Thurs, Sep 2 2010 7:43 pm
From: "John Keiser"

I use it to splice "O" rings into custom sizes. If done properly [clean
single edge razor blade, square cut] holds up well as a VCR drive belt,
even in a swimming pool vacuum line leaf trap. Using a telfon "v" block
would help alignment but I've managed without.
.

"AZ Nomad" <aznomad.3@PremoveOBthisOX.COM> wrote in message
news:slrni80d99.pl9.aznomad.3@ip70-176-155-130.ph.ph.cox.net...
> On Thu, 2 Sep 2010 11:20:39 -0700, Dave Platt <dplatt@radagast.org> wrote:
>>>Surprising I've never done it before . Thumb and second finger firmly
>>>glued
>>>to either side of a connecctor. I tried methylated spirits first but no
>>>effect seemingly. Then dilute acetone as nail varnish remover. I was
>>>concerned about being too long on the skin so some cotton wool balls of
>>>acetone around both areas and a Q-tip soaked in acetone, with a rotating
>>>wedge-like motion, cautiously wedging skin from connector worked, but
>>>anyone
>>>elses experiences/advice for the next time?
>
>>Keeping a bottle of superglue debonder around is a cheap investment.
>>If you go to a hobby store which carries a selection of cyanoacrylate
>>glues (usually of different viscosities and bonding speeds) you ought
>>to find a supply of debonder in the same rack.
>
>
> Has anybody ever found an application where superglue works well
> except on human skin? I find the crap brittle as hell and have yet to
> see anything glued with it last more than a few weeks before breaking.

== 7 of 10 ==
Date: Thurs, Sep 2 2010 8:01 pm
From: Jeff Liebermann

On Thu, 2 Sep 2010 16:43:03 -1000, "John Keiser"
<john.keiser2@hawaiiantel.net> wrote:

>I use it to splice "O" rings into custom sizes. If done properly [clean
>single edge razor blade, square cut] holds up well as a VCR drive belt,
>even in a swimming pool vacuum line leaf trap. Using a telfon "v" block
>would help alignment but I've managed without.

The square cut (butt splice) doesn't work well. The problem is that
the hardened super glue goes across the diameter of the rubber o-ring.
If this diameter is compressed in any way, the superglue cracks, and
the o-ring falls apart. This is especially important for internal
o-ring seals, which use o-ring compression to maintain pressure. I've
done bench tests on various methods and found butt splices lacking. It
will work with a flexible adhesive, such as RTV, but not rock hard CA
glues.

Instead, try a 45 degree bevel cut. If you have an old 1/4" magnetic
tape splicer, there's usually a form and guillotine blade suitable for
the purpose. I do it without any alignment aids, which is good
enough. My favorite cutting device is a safety razor or surgeons
scalpel.

When glued at a 45 degree angle, you get a larger surface contact area
for the glue. The joint is also less in tension and more in shear,
which does make it slightly weaker. I haven't noticed any measureable
difference when I did some stretch tests. The 45 degree splice also
allows the o-ring to be compressed in almost all orientations, without
cracking the CA glue joint.

--
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

== 8 of 10 ==
Date: Thurs, Sep 2 2010 8:29 pm
From: isw

In article <slrni80d99.pl9.aznomad.3@ip70-176-155-130.ph.ph.cox.net>,
AZ Nomad <aznomad.3@PremoveOBthisOX.COM> wrote:

> On Thu, 2 Sep 2010 11:20:39 -0700, Dave Platt <dplatt@radagast.org> wrote:
> >>Surprising I've never done it before . Thumb and second finger firmly glued
> >>to either side of a connecctor. I tried methylated spirits first but no
> >>effect seemingly. Then dilute acetone as nail varnish remover. I was
> >>concerned about being too long on the skin so some cotton wool balls of
> >>acetone around both areas and a Q-tip soaked in acetone, with a rotating
> >>wedge-like motion, cautiously wedging skin from connector worked, but anyone
> >>elses experiences/advice for the next time?
>
> >Keeping a bottle of superglue debonder around is a cheap investment.
> >If you go to a hobby store which carries a selection of cyanoacrylate
> >glues (usually of different viscosities and bonding speeds) you ought
> >to find a supply of debonder in the same rack.
>
>
> Has anybody ever found an application where superglue works well
> except on human skin? I find the crap brittle as hell and have yet to
> see anything glued with it last more than a few weeks before breaking.

I dropped my "Arkansas white" stone while putting the finishing touches
on a kitchen knife. The break was right across the middle of the 7" long
stone. I put a bit of superglue on the broken surface and pressed the
parts back together. The pieces went together so well that you can't
see, much less feel, the break. And the stone is still going strong
after more than fifteen years.

Isaac

== 9 of 10 ==
Date: Thurs, Sep 2 2010 9:45 pm
From: whit3rd

On Sep 2, 4:37 pm, AZ Nomad <aznoma...@PremoveOBthisOX.COM> wrote:

> Has anybody ever found an application where superglue works well
> except on human skin?  I find the crap brittle as hell and have yet to
> see anything glued with it last more than a few weeks before breaking.

Sure. It worked fine for me gluing carbide to tool steel. Far from
brittle, it was the most compliant of the three materials.
It held a ton or so of force in another application, gluing
stainless tapers together (for an ultrasonic drill tip).

== 10 of 10 ==
Date: Fri, Sep 3 2010 12:28 am
From: "N_Cook"

Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote in message
news:4C80375D.4020906@electrooptical.net...
> AZ Nomad wrote:
> > On Thu, 2 Sep 2010 11:20:39 -0700, Dave Platt <dplatt@radagast.org>
wrote:
> >>> Surprising I've never done it before . Thumb and second finger firmly
glued
> >>> to either side of a connecctor. I tried methylated spirits first but
no
> >>> effect seemingly. Then dilute acetone as nail varnish remover. I was
> >>> concerned about being too long on the skin so some cotton wool balls
of
> >>> acetone around both areas and a Q-tip soaked in acetone, with a
rotating
> >>> wedge-like motion, cautiously wedging skin from connector worked, but
anyone
> >>> elses experiences/advice for the next time?
> >
> >> Keeping a bottle of superglue debonder around is a cheap investment.
> >> If you go to a hobby store which carries a selection of cyanoacrylate
> >> glues (usually of different viscosities and bonding speeds) you ought
> >> to find a supply of debonder in the same rack.
> >
> >
> > Has anybody ever found an application where superglue works well
> > except on human skin? I find the crap brittle as hell and have yet to
> > see anything glued with it last more than a few weeks before breaking.
>
> I use it on optical things often, because it's easily removed, like Duco
> cement except stronger and faster-setting. As long as you use just a
> little, it doesn't cause too much nasty frosting nearby.
>
> Cheers
>
> Phil Hobbs
>
> --
> Dr Philip C D Hobbs
> Principal
> ElectroOptical Innovations
> 55 Orchard Rd
> Briarcliff Manor NY 10510
> 845-480-2058
> hobbs at electrooptical dot net
> http://electrooptical.net

How do you use "just a little" with the viscosity almost of liquid helium
and coming in aluminium tubes of a gauge almost the same as tin cans it
seems impossible to squeeze out a small drop, only. I must adopt the storage
in small airtight bottle with (non cotton) sachet of activated silica gel
inside. Hopefully then it will be more amenable to squeezing out just enough
to wet a needle point to transfer to the intended.

==============================================================================
TOPIC: Yet another bulging-capacitors replacement
http://groups.google.com/group/sci.electronics.repair/t/3ec97de65fce9bb3?hl=en
==============================================================================

== 1 of 3 ==
Date: Thurs, Sep 2 2010 6:04 pm
From: "Arfa Daily"

"Jeff Liebermann" <jeffl@cruzio.com> wrote in message
news:avlv76lbbv730nj64qmotl19k485ah8ji4@4ax.com...
> On Thu, 02 Sep 2010 09:54:44 -0700, Jeff Liebermann <jeffl@cruzio.com>
> wrote:
>
>>The thermal conductivity of G10/FR4 isn't all that wonderful,
> (...)
>
> Ok, let's do the numbers. The coefficient of thermal expansion for
> G10/FR4 is:
> 1*10^-5 cm/cm/C
> That means a 1 cm long piece of G10/FR4, will expand 1*10^-5 cm for
> every degree C of temperature differential.
>
> So, we have a big fat BGA chip, that's about 5cm across. It's running
> hot with a bottom temperature of about 80C. Assuming the PCB is
> running at room temp of 25C, that's a 55C differential temperature.
> Over the diameter of the BGA, that's
> 125*10^-5 cm
> movement of the PCB.
>
> Solder balls come in all manner of sizes, but my guess(tm) that for a
> 1mm pitch BGA, a 0.4mm ball is appropriate. When soldered, the ball
> will remain about the same diameter, but the height will be reduced to
> about 0.1mm.
>
> The angle that the ball moves over temperature is:
> angle = arctan ( 125*10^-5 cm / 0.01cm ) = arctan 0.125
> angle = 7 degrees
> which is a fair amount of ball rotation. Do that often enough, and
> the ball will "roll" itself off the pad. For a sanity check, solder a
> rigid bar of something to a flat surface, and bend it back and forth
> about 7 degrees. It will take a while, but it will eventually break.
>
>
> --
> Jeff Liebermann jeffl@cruzio.com

Great info and insights in both posts as always Jeff. I will take them into
consideration. The temperature differential thing is something that I hadn't
considered, but following through your numbers, seems to be a very valid
point ...

Arfa

== 2 of 3 ==
Date: Thurs, Sep 2 2010 7:36 pm
From: Jeff Liebermann

On Fri, 3 Sep 2010 02:04:18 +0100, "Arfa Daily"
<arfa.daily@ntlworld.com> wrote:

>
>
>"Jeff Liebermann" <jeffl@cruzio.com> wrote in message
>news:avlv76lbbv730nj64qmotl19k485ah8ji4@4ax.com...
>> On Thu, 02 Sep 2010 09:54:44 -0700, Jeff Liebermann <jeffl@cruzio.com>
>> wrote:
>>
>>>The thermal conductivity of G10/FR4 isn't all that wonderful,
>> (...)
>>
>> Ok, let's do the numbers. The coefficient of thermal expansion for
>> G10/FR4 is:
>> 1*10^-5 cm/cm/C
>> That means a 1 cm long piece of G10/FR4, will expand 1*10^-5 cm for
>> every degree C of temperature differential.
>>
>> So, we have a big fat BGA chip, that's about 5cm across. It's running
>> hot with a bottom temperature of about 80C. Assuming the PCB is
>> running at room temp of 25C, that's a 55C differential temperature.
>> Over the diameter of the BGA, that's
>> 125*10^-5 cm
>> movement of the PCB.
>>
>> Solder balls come in all manner of sizes, but my guess(tm) that for a
>> 1mm pitch BGA, a 0.4mm ball is appropriate. When soldered, the ball
>> will remain about the same diameter, but the height will be reduced to
>> about 0.1mm.
>>
>> The angle that the ball moves over temperature is:
>> angle = arctan ( 125*10^-5 cm / 0.01cm ) = arctan 0.125
>> angle = 7 degrees
>> which is a fair amount of ball rotation. Do that often enough, and
>> the ball will "roll" itself off the pad. For a sanity check, solder a
>> rigid bar of something to a flat surface, and bend it back and forth
>> about 7 degrees. It will take a while, but it will eventually break.

>Great info and insights in both posts as always Jeff. I will take them into
>consideration. The temperature differential thing is something that I hadn't
>considered, but following through your numbers, seems to be a very valid
>point ...

Well, I did manage to make one mistake. The 7 degrees is the worst
case bending angle assuming everything accumulates in one direction.
That's not the case as local heating of the PCB will be from the
center outward. Instead of 125*10^-5 cm of lengthening measured from
the edge, the PCB will elongate half that amount, measured from the
center of the BGA. Correcting accordingly:

The angle that the ball moves over temperature is:
angle = arctan ( 63*10^-5 cm / 0.01cm ) = arctan 0.063
angle = 3.5 degrees
That's still enough to tear apart the solder ball, but not as radical
as I previously suggested.

One solution is to use a BGA adapter socket. Obviously, this isn't
going to work inside a laptop, where vertical height is a major
limitation. Same with some desktops, where the CPU heatsink and fan
can only be so tall or air flow out the top of the heatsink and fan
will be constricted. I've never tried to retrofit one of these into
an existing motherboard, but it sure looks tempting.
<http://www.advanced.com/bgastart.html>
<http://www.mill-max.com/products/newproducts_detail.cfm?pid=7>
<http://www.ironwoodelectronics.com/products/adapters/giga_snap.cfm>

--
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

== 3 of 3 ==
Date: Thurs, Sep 2 2010 10:24 pm
From: Mike Tomlinson

In article <pXKfo.13668$45.9048@newsfe29.ams2>, Arfa Daily
<arfa.daily@ntlworld.com> writes

>I have always been sparing with compound - and I
>use a lot of it as I repair many big amps for a living - but it is a fact
>that a very thin translucent layer of white, is not effective enough on a
>standard non-flatted device face, and heatsink contact area, whereas with
>AS, it would appear that it is.

Have you tried applying the white stuff to both surfaces, then scraping
it off with the edge of a card? That will fill in any valleys on both
surfaces, and you should get a good thermal bond with the minimum of
compound.

This is the method that AS suggest using, by the way.

--
(\__/)
(='.'=)
(")_(")

==============================================================================
TOPIC: Why we have Gravity
http://groups.google.com/group/sci.electronics.repair/t/004d04dfe74c9553?hl=en
==============================================================================

== 1 of 1 ==
Date: Thurs, Sep 2 2010 8:41 pm
From: RichTravsky

"Michael A. Terrell" wrote:
> RichTravsky wrote:
> > Bob Villa wrote:
> > ? On Aug 23, 2:50 pm, "Michael A. Terrell" ?mike.terr...@earthlink.net?
> > ? wrote:
> > ? ? Bob Villa wrote:
> > ? ? ? On Aug 23, 12:24 pm, "Michael A. Terrell" ?mike.terr...@earthlink.net?
> > ? ? ? wrote:
> > ? ? ? ? RichTravsky wrote:
> > ? ? ? ? ? fitz wrote:
> > ? ?
> > ? ? ? ? ? ? Why we have Gravity
> > ? ?
> > ? ? ? ? ? ? A correct theory of gravity will show us these four (4) things:
> > ? ? ? ? ? ? 1. It will show us why gravity also acts like acceleration (principle
> > ? ? ? ? ? ? of equvalence).
> > ? ? ? ? ? ? 2. It will show us the actual cause of gravity.
> > ? ? ? ? ? ? 3. It will show us why gravitational mass and inertial mass are
> > ? ? ? ? ? ? identical.
> > ? ? ? ? ? ? 4. It will show us the speed of gravitational attraction.
> > ? ?
> > ? ? ? ? ? ? Newton said gravity was acting at a much faster speed than Einstein.
> > ? ?
> > ? ? ? ? ? Well, the average running speed of a human is around 10 mph. Sprints, the
> > ? ? ? ? ? record is under 30 mph. I don't know how athletic Einstein was so we could
> > ? ? ? ? ? use a figure of 3 mph walking speed. Nice to set some lower boundaries
> > ? ? ? ? ? on the SoG (speed of gravity).
> > ? ?
> > ? ? ? ? Slow Old Geezers.
> > ? ?
> > ? ? ? I resemble that remark!
> > ? ?
> > ? ? Admitting it is the first step to recovery! ;-)
> > ?
> > ? There is no recovery...slow, old geezers only get slower.
> >
> > And older...
>
> The alternative is worse...

There is no alternative. Not really ;)

==============================================================================
TOPIC: Technics KN800 MIDI keyboard no sound
http://groups.google.com/group/sci.electronics.repair/t/f95dad92d98851fc?hl=en
==============================================================================

== 1 of 1 ==
Date: Thurs, Sep 2 2010 11:01 pm
From: GeoffC

Geoff C <not@mail.com> wrote in
news:Xns9DE733AE1C5EEGeoffC@188.40.43.230:

> I was given a Technics SX-KN800 keyboard and am trying to repair it. I
> have opened it up and the six or so PCB's are easy to get at. The
> symptom is no audio. The PA thumps through the speakers on turn off
> and the PA has power supply OK so it is not a concern at the moment.
> The line out has no audio either. Of course it is possible that a
> crash has occured but I cannot find a reset so far. No audio is
> getting to the PA. I could not find any signal at the master volume
> either, though it may not have real signal at it.
>
> I believe it was made early to mid 90's. There are a lot of Technics
> proprietery chips in it. I have an op manual for a KN1000 which is
> similar, but no schematics appear anywhere I have seen.
>
> What I would like to know is a general question about how the audio
> signal is generated from the PCM pulse stream. It may be a simple LPF
> from a digital chip which regenerates the audio, or there may be a
> specialised audio chip to look for? If I can't go much further I will
> have to junk it.
>

I have fixed it so I thought I'd follow up the fix. There was no -15 volt
rail due to a 4.7 ohm fusible resistor on the main board being open. This
was adjacent to the connector which received the power supplies from the
power amp/power supply board.

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