sci.electronics.repair@googlegroups.com

Today's topics:

* Weird stuff -- update -- (was Electronic Kenmore refrigerator not working,
what does this sign mean) - 5 messages, 5 authors
http://groups.google.com/group/sci.electronics.repair/t/90e33648f2879de5?hl=en
* Plasma TV Foggy area - 1 messages, 1 author
http://groups.google.com/group/sci.electronics.repair/t/9e5cdc2b5ff03be3?hl=en
* Yet another bulging-capacitors replacement - 2 messages, 2 authors
http://groups.google.com/group/sci.electronics.repair/t/3ec97de65fce9bb3?hl=en
* Supergluing your fingers together - 2 messages, 1 author
http://groups.google.com/group/sci.electronics.repair/t/27d3b5cbe57935fb?hl=en

==============================================================================
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 5 ==
Date: Fri, Sep 3 2010 5:22 pm
From: aemeijers

On 9/3/2010 2:37 PM, HeyBub wrote:
> DerbyDad03 wrote:
>>
>> re: "when something stops working when you put the lid on, that tells
>> me the lid is somehow binding something up or shorting something out."
>>
>> In a much earlier life, I used to install and repair Radio Shack
>> TRS-80 workstations. My company also used the Storage Expansion Unit
>> which could house up to three additional 8? drives as shown here:
>>
>> http://www.trs-80.com/wordpress/trs-80-computer-line/model-ii/
>>
>> These expansion bays were notorious for not working once you put the
>> cover back on. You'd repair the unit or add a drive, test all three
>> drives with the cover off and then install the cover and the 84,000
>> screws that kept it on. Invariably, one of the drives (it would be
>> random as to which one) would no longer be accessible.
>>
>> You had to loosen screws, tweak the cover, slap the box, whatever, to
>> get it working.
>>
>> With hundreds of these workstations installed in everything from
>> offices to chemical processing areas, you can be sure that we did a
>> lot of bench work trying to determine what the problem was in an
>> effort to make our on-site work easier. We never figured it out and
>> were thrilled when they started replacing them with the original IBM
>> PC.
>
> The problem hasn't gone away.
>
> We've been farkin' with a CD duplicator for a month. It would randomly fail
> to eject a CD. Replacement of the CD drive with a new one didn't help. We
> finally got it to work flawlessly but when we tightened the screws holding
> the drive in place, back to the same symptom.
>
> Turns out, tightening the screws distorted the drive (made of old beer-can
> metal).
>
> Loosening the screws somewhat returned the duplicator to perfect
> functioning.
>
>

Snort. I used to see that issue in brand new PCs just out of the crate-
hard drive had 2 screws on one side, but only one on the other. Thought
it was a production boo-boo, so started checking all the other ones as I
was installing the memory upgrades and tape drives (yeah, this was a few
years ago), and they were all like that. Only using 3 screws was a real
common trick on early CD drives, before they got the hang of designing
them cheap but stiff.

--
aem sends...

== 2 of 5 ==
Date: Fri, Sep 3 2010 5:38 pm
From: PeterD

On Fri, 3 Sep 2010 13:04:45 +0000 (UTC), Hugh Jassolle <hj@yaho.orq>
wrote:

>On Fri, 03 Sep 2010 08:45:03 -0400, PeterD wrote:
>
>> On Thu, 02 Sep 2010 19:03:20 -0500, 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?
>>>
>>>i
>>
>> hell, my fridge has done that for years... (Really, it has).
>>
>> The reason is 'high head pressure' and you have to let it sit for as
>> much as 20 to 30 minutes (typically, but can be longer) between startup
>> cycles.
>
>Shouldn't take 20 minutes for the head pressure to bleed off enough for a
>restart. Unless of course there is a partial restriction in the high
>side. If the system has moisture in the freon the end of the cap tube can
>ice up causing a restriction. Or some contaminates could plug the cap
>tube partially. Normally the head pressure should reduce sufficiently to
>allow a proper working compressor to restart in 5 minutes or less.

No it souldn't except when the unit has been moved and possibly oil is
in the 'wrong' places and must drain back. THen it can take 20
minutes. But to expect a person to determine this condition is not
realistic, so I recommend 20 minutes.

(Even your estimate of 5 minutes is usually much more than is needed,
I've seen them bleed down in under two minutes.)

== 3 of 5 ==
Date: Fri, Sep 3 2010 8:07 pm
From: "Michael A. Terrell"

DerbyDad03 wrote:
>
> On Sep 3, 11:55Â am, "Michael A. Terrell" <mike.terr...@earthlink.net>
> wrote:
> > DerbyDad03 wrote:
> >
> > > re: "when something stops working when you put the lid on, that tells
> > > me the lid is somehow binding something up or shorting something out."
> >
> > > In a much earlier life, I used to install and repair Radio Shack
> > > TRS-80 workstations. My company also used the Storage Expansion Unit
> > > which could house up to three additional 8″ drives as shown here:
> >
> > >http://www.trs-80.com/wordpress/trs-80-computer-line/model-ii/
> >
> > > These expansion bays were notorious for not working once you put the
> > > cover back on. You'd repair the unit or add a drive, test all three
> > > drives with the cover off and then install the cover and the 84,000
> > > screws that kept it on. Invariably, one of the drives (it would be
> > > random as to which one) would no longer be accessible.
> >
> > > You had to loosen screws, tweak the cover, slap the box, whatever, to
> > > get it working.
> >
> > > With hundreds of these workstations installed in everything from
> > > offices to chemical processing areas, you can be sure that we did a
> > > lot of bench work trying to determine what the problem was in an
> > > effort to make our on-site work easier. We never figured it out and
> > > were thrilled when they started replacing them with the original IBM
> > > PC.
> >
> > Â Â They cut one corner too many by tin plating the edge connectors, then
> > plugging them into connectors with gold plated contacts. Â At one time
> > there was a special connector sold that you soldered to the tin plate,
> > and had gold plated contacts to mate with the ribbon cables.
> >
> > --
> > Politicians should only get paid if the budget is balanced, and there is
> > enough left over to pay them.
>
> re: "At one time there was a special connector sold that you soldered
> to the tin plate, and had gold plated contacts to mate with the ribbon
> cables."
>
> Trust me, I know all about the many corners they cut! ;-)
>
> However, how would this particular connector issue be impacted by the
> installation of the case? The case had no connectors, it was just a
> metal shell.

Some cases put pressure on one side of the ribbon connector. The
modification extended it outside of the case. I repaired a lot of early
computers, too.

> P.S. Before installing the TRS-80's, we opened up every keyboard and
> ran a wire from the circuit board ground to the plastic case. Before
> we did that, weird things would happen when the user touched the
> keyboard.
>
> The worst was seeing the disk drive light turn on and knowing that the
> program and/or data disk was now corrupt. The least was hearing the
> daisy wheel printer print out a single character.
>
> We had some users that were so paranoid about their data that they
> wired a grounding bracelet to the sprinkler system and would hook
> themselves up before they touched the system.

--
Politicians should only get paid if the budget is balanced, and there is
enough left over to pay them.

== 4 of 5 ==
Date: Fri, Sep 3 2010 8:32 pm
From: The Daring Dufas

On 9/3/2010 9:06 AM, DerbyDad03 wrote:
> On Sep 2, 8:30 pm, aemeijers<aemeij...@att.net> wrote:
>> On 9/2/2010 8:03 PM, 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?
>>
>> Take the cover back off and see if anything changes? Mebbe fridge got
>> shoved into the wall, and the cover got bent, and is making something
>> not work?
>>
>> I'm no fridge expert, but when something stops working when you put the
>> lid on, that tells me the lid is somehow binding something up or
>> shorting something out.
>>
>> --
>> aem sends...
>
> re: "when something stops working when you put the lid on, that tells
> me the lid is somehow binding something up or shorting something out."
>
> In a much earlier life, I used to install and repair Radio Shack
> TRS-80 workstations. My company also used the Storage Expansion Unit
> which could house up to three additional 8″ drives as shown here:
>
> http://www.trs-80.com/wordpress/trs-80-computer-line/model-ii/
>
> These expansion bays were notorious for not working once you put the
> cover back on. You'd repair the unit or add a drive, test all three
> drives with the cover off and then install the cover and the 84,000
> screws that kept it on. Invariably, one of the drives (it would be
> random as to which one) would no longer be accessible.
>
> You had to loosen screws, tweak the cover, slap the box, whatever, to
> get it working.
>
> With hundreds of these workstations installed in everything from
> offices to chemical processing areas, you can be sure that we did a
> lot of bench work trying to determine what the problem was in an
> effort to make our on-site work easier. We never figured it out and
> were thrilled when they started replacing them with the original IBM
> PC.
>

Back in the late 70's I worked for Tandy repair and most of the trouble
with their equipment was caused by cold solder joints. The connections
made with plated through holes on the circuit board were always suspect.

TDD

== 5 of 5 ==
Date: Fri, Sep 3 2010 9:10 pm
From: "Martin H. Eastburn"

Vapor lock. Likely a little light on freon and the pump shutting off
gets a high head pressure and can't push up to clear it.

Likely in the off position, it will leak pass a gasket and it will start.

That is my suspect. Might be that way only when hot. e.g. just running.

Might work in the shop all winter if cold out there - lightly running and
cold coils. Warm house shuts it down.

That is what I figure.

Martin

Martin H. Eastburn
@ home at Lions' Lair with our computer lionslair at consolidated dot net
"Our Republic and the Press will Rise or Fall Together": Joseph Pulitzer
TSRA: Endowed; NRA LOH & Patron Member, Golden Eagle, Patriot's Medal.
NRA Second Amendment Task Force Originator & Charter Founder
IHMSA and NRA Metallic Silhouette maker & member. http://lufkinced.com/

On 9/2/2010 7:03 PM, 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

==============================================================================
TOPIC: Plasma TV Foggy area
http://groups.google.com/group/sci.electronics.repair/t/9e5cdc2b5ff03be3?hl=en
==============================================================================

== 1 of 1 ==
Date: Fri, Sep 3 2010 5:58 pm
From: "Arfa Daily"

"Michael Kennedy" <mike@nospam.com> wrote in message
news:7vqdnYbfH6htixzRnZ2dnVY3goWdnZ2d@giganews.com...
>
> "AZ Nomad" <aznomad.3@PremoveOBthisOX.COM> wrote in message
> news:slrni825ad.gkr.aznomad.3@ip70-176-155-130.ph.ph.cox.net...
>> On Sat, 4 Sep 2010 00:18:51 +0900, Michael Kennedy <mike@nospam.com>
>> wrote:
>>
>>>"Meat Plow" <mhywatt@yahoo.com> wrote in message
>>>news:pan.2010.09.03.14.59.46@hahahahahahahah.nutz.I.am...
>>>> On Fri, 03 Sep 2010 23:45:09 +0900, Michael Kennedy wrote:
>>>>
>>>>> I don't have this tv in hand now and also don't have the make and
>>>>> model
>>>>> of this display at the moment but all I am looking for is general
>>>>> information for now.
>>>>>
>>>>> This tv has a smudged / blurry area on the screen. It looks almost
>>>>> like
>>>>> it is dirty from a oily hand but it doesn't wipe off. It is not a
>>>>> rectangular area.
>>>>>
>>>>> I am not familar with the common failure modes of Plasma displays.
>>>>> What
>>>>> is your best guess would cause this.
>>>>>
>>>>> Thanks in advance,
>>>>>
>>>>> Mike
>>>>
>>>> Since it only covers a non-symmetrical portion of the screen my
>>>> guestimate would be the screen itself.
>>>>
>>
>>>Thanks for the insight Meat.
>>
>>>These aren't affected by magnets the way CRT sets are they? Sorry for the
>>>stupid questions, but I have never taken apart, owned or even used a
>>>plasma
>>>display. I am only familiar with the VERY basic principles of operation
>>>and
>>>know it uses phosphors which are similar to a CRT but uses some other
>>>method
>>>to illuminate the phosphors. I guess uses some kind of micro printed
>>>circuitry similar to an LCD display, but I could be totally wrong about
>>>that.
>>
>> There is no convergance nor is there any concept of focussing. The
>> pixels are fixed in size and location and nothing can affect that.
>
> That's the question I was wondering.. Thanks!
> I've got a little better idea of how this thing works now. Before it was
> all speculation.
>

It was not unknown for plasma cells on older panels to develop a 'memory' of
some bright content that had been displayed, resulting in a sort of visible
'stain'. In the worst case, this could cause permanent damage to the cells
in the area, but often, the effect could be negated with a special service
mode that did an intense white wipe of the panel. I'm pretty sure that
modern panels don't suffer from this problem, and are much less susceptible
to cell burn from high intensity static displays, but if the set is more
than a few years old, it might be worth checking to see if there is a
service mode that carries out a panel wipe. It may even be available as a
user function through one of the menus.

Have a read of

http://en.wikipedia.org/wiki/Plasma_display

For a good description of the principles involved

Arfa

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

== 1 of 2 ==
Date: Fri, Sep 3 2010 6:07 pm
From: "Arfa Daily"

"Jeff Liebermann" <jeffl@cruzio.com> wrote in message
news:gbg286hlovdiatsohrjhb9g0p92g92ocok@4ax.com...
> On Fri, 3 Sep 2010 06:24:11 +0100, Mike Tomlinson <mike@jasper.org.uk>
> wrote:
>
>>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.
>
> I've always suspected that it's a conspiracy by the manufacturer to
> consume more expensive Artic Silver. Kinda like washing your hair
> twice with "pH balance" shampoo.
>
> The best heat tranfer between heat sink and CPU is metal to metal
> contact, with no grease. The problem is that neither the heat sink or
> CPU lid are flat and have pits, holes, gouges, lumps, cavities, and
> other problems that prevent good contact. Even without these problem,
> and with a mirror finish base, the typical warped package and
> non-stress relieved heat sink, will not produce proper metal to metal
> contact (without extreme mechanical pressure). My guess(tm) is that a
> typical "brushed" aluminum heat sink to a Pentium 4 package might have
> 30% or less metal to metal contact. This sucks.
>
> The idea is to fill the pits, holes, gouges, lumps, cavities, etc with
> something thermally conductive, thus eliminating the need for mirror
> finished and flat CPU's and heat sinks. The trick is to only fill the
> pits, holes, gouges, lumps, cavities, etc and still retain as much
> metal to metal contact as possible. That's not going to happen if you
> use too much. As a clue, see the thermal resistance spec for Artic
> Silver at:
> <http://www.arcticsilver.com/as5.htm>
> Thermal Resistance:
> 0.0045°C-in^2/Watt (0.001 inch layer)
> Notice the 0.001 inch (0.025mm) layer. That's really really really
> thin. So thin, that you could probably not even see it on the surface
> because most of the stuff is in the pits, holes, gouges, lumps,
> cavities, etc. If it had been specified with a thicker layer, the
> thermal resistance would have been much worse.
>
> It's probably a good idea to smear on some Artic Silver on both sides
> of the junction, but then wipe off everything except what's in the
> pits, holes, gouges, lumps, cavities, etc leaving as much metal to
> metal contact as possible. If you're dealing with a badly warped or
> an unpolished casting, then a little more grease might justifiable.
> However, packing it on in a thick layer, but doing both sides, is a
> waste.
>
> --
> Jeff Liebermann jeffl@cruzio.com

All agreed

Arfa

== 2 of 2 ==
Date: Fri, Sep 3 2010 6:34 pm
From: Jeff Liebermann

On Sat, 4 Sep 2010 02:07:59 +0100, "Arfa Daily"
<arfa.daily@ntlworld.com> wrote:

>All agreed
>Arfa

Nobody ever agrees with me. I must have said something wrong.

See:
<http://www.microsi.com/packaging/thermal_grease.htm>
Notice what happens to the thermal resistance as the thickness of the
silicon grease layer increases. Also notice the comment about
"solvent evaporation" which is why Arctic Silver and other greases
takes a while to "break-in".

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

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

== 1 of 2 ==
Date: Fri, Sep 3 2010 8:47 pm
From: isw

In article <i5q87b$5is$1@news.eternal-september.org>,
"N_Cook" <diverse@tcp.co.uk> wrote:

> 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.

Easy; you just smear it on with your finger 8^}

Isaac

== 2 of 2 ==
Date: Fri, Sep 3 2010 8:50 pm
From: isw

In article <e9a18692kkr82i2c0vu3dd6oij5835kg0t@4ax.com>,
Jeff Liebermann <jeffl@cruzio.com> wrote:

> On Fri, 3 Sep 2010 08:28:29 +0100, "N_Cook" <diverse@tcp.co.uk> wrote:
>
> >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.
>
> There's a trick. I use bottles with a stainless tube for dispensing
> cyanoacrylate adhesive. Something like this.
> <http://www.technologylk.com/weld-on-applicator-bottle-with-needle-lk-AAB4.htm
> >
> <http://www.hobbylinc.com/htm/mmr/mmrmkdbp.htm>
>
> As soon as you use it, the stainless tip will clog. No problem. Find
> a cancer stick igniter, and heat the stainless barrel. There will be
> a small puff of noxious smog as the CA burns off, and the tip is
> clear.
>
> It's quite easy to dispense just one drop with a stainless tip and
> quite difficult with a CA encrusted plastic tip commonly found in the
> hardware store CA products. If you want a smaller drop, try a smaller
> dispenser barrel.

Some newer formulations can be brushed on; they don't go off as fast,
and it's a lot easier to get the joint properly aligned than it used to
be.

Also, some formulations will work fine with things like paper or
cardboard, too.

Isaac

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