sci.electronics.repair@googlegroups.com

Today's topics:

* Annoying Clock on Microwave - 8 messages, 8 authors
http://groups.google.com/group/sci.electronics.repair/t/408849711f765a28?hl=en
* Lead free solder - 12 messages, 7 authors
http://groups.google.com/group/sci.electronics.repair/t/7ff46ef49e9b7de3?hl=en
* Really "need to" replace older CATV cables? Would my cable provider really
filter my line against my will? - 2 messages, 2 authors
http://groups.google.com/group/sci.electronics.repair/t/31e43b6766887486?hl=en
* Toshiba Satellite Pro M15-S405 PCB flux rot - 1 messages, 1 author
http://groups.google.com/group/sci.electronics.repair/t/5f474e30d60254b9?hl=en
* Denon DN-A7100 surround preamp - 1 messages, 1 author
http://groups.google.com/group/sci.electronics.repair/t/11d516c552e831ed?hl=en
* 42" Panasonic plasma TV model: TH-42PX60U dead - 1 messages, 1 author
http://groups.google.com/group/sci.electronics.repair/t/c8e947a6771af994?hl=en
* A specific PCB bad practise, term for it ? - 1 messages, 1 author
http://groups.google.com/group/sci.electronics.repair/t/8689adb4b80bfe29?hl=en

==============================================================================
TOPIC: Annoying Clock on Microwave
http://groups.google.com/group/sci.electronics.repair/t/408849711f765a28?hl=en
==============================================================================

== 1 of 8 ==
Date: Sat, Apr 23 2011 12:46 am
From: Adrian C

On 22/04/2011 18:35, jeff_wisnia wrote:
>
> From my "I can't believe they'd make it this way" list.
>
> Last year I purchased a new Westinghouse Model WST-3501 microwave oven
> for our office lunchroom.
>
> It heats and cooks things fine, but has one lousy feature which I can't
> avoid noticing and which irks me very time I see it.
>
> The TOD, which is displayed whenever the unit is on standby, loses about
> two minutes a day, and has to be reset every few days to keep from
> falling ridiculously behind.
>
> I'm shocked, shocked, that the clock isn't synced to the 120 volt 60 Hz
> power the unit runs on, like every other line powered appliance with a
> digital TOD display I own.
>
> The only reason I can guess for the poor timekeeping is that the
> circuitry/board running the clock is used on their 220 volt 50 Hz
> versions without modification, so the makers decided not to use line
> sync for the clock, and probably didn't want to spring for a crystal
> oscillator either, so used an RC one instead.
>
> I tried emailing Westinghouse about this and they fobbed me off to a
> subsidiary who couldn't even bother to respond to an email.
>
> Thanks for reading. Anyone got any other ideas about why the stupid
> clock in this microwave loses time?

Probably the clock is line sync'd, and then when cooking, is magnetron
supply sync'd - as critically voltage is lost at the connection point
where the clock takes its time period sample.

Try not cooking for a day and see if that fixes the time loss, then try
using a shorter or heavier cable for the line connection?

--
Adrian C

== 2 of 8 ==
Date: Sat, Apr 23 2011 1:26 am
From: David Nebenzahl

On 4/22/2011 10:27 PM John Tserkezis spake thus:

> Consider this: A microwave oven doesn't need a clock at all, just a
> timekeeper for timed cooking. Accuracy is not a priority here at all.
> The fact they have clocks at all means the manufacturers wanted to get
> one leg up on the competitors without expending any money.
>
> We're not talking cameras in cellphones here, there is NO reason for
> them to make their clocks accurate, because non of the competition are
> going to bother either.

True now, no doubt, but wasn't always so. My Magic Chef, which I got
used, lessee, 23 years ago or so and still works perfectly, has a very
accurate clock. Crystal-controlled, I'm going to guess.

--
The current state of literacy in our advanced civilization:

yo
wassup
nuttin
wan2 hang
k
where
here
k
l8tr
by

- from Usenet (what's *that*?)

== 3 of 8 ==
Date: Sat, Apr 23 2011 5:05 am
From: "William Sommerwerck"

"David Nebenzahl" <nobody@but.us.chickens> wrote in message
news:4db28ccc$0$10024$822641b3@news.adtechcomputers.com...

> My Magic Chef, which I got used, lessee, 23 years ago
> or so and still works perfectly, has a very accurate clock.
> Crystal-controlled, I'm going to guess.

In the US, line frequency used to be (and probably still is) "tweaked" so
that clocks with synchronous motors would have zero net error over a long
period of time. This should give better accuracy than a crystal.

== 4 of 8 ==
Date: Sat, Apr 23 2011 5:49 am
From: Bob Villa

On Apr 22, 12:35 pm, jeff_wisnia <jwisniaDumpThisP...@conversent.net>
wrote:
>  From my "I can't believe they'd make it this way" list.
>
> Last year I purchased a new Westinghouse Model WST-3501 microwave oven
> for our office lunchroom.
>
> It heats and cooks things fine, but has one lousy feature which I can't
> avoid noticing and which irks me very time I see it.
>
> The TOD, which is displayed whenever the unit is on standby, loses about
> two minutes a day, and has to be reset every few days to keep from
> falling ridiculously behind.
>
> I'm shocked, shocked, that the clock isn't synced to the 120 volt 60 Hz
> power the unit runs on, like every other line powered appliance with a
> digital TOD display I own.
>
> The only reason I can guess for the poor timekeeping is that the
> circuitry/board running the clock is used on their 220 volt 50 Hz
> versions without modification, so the makers decided not to use line
> sync for the clock, and probably didn't want to spring for a crystal
> oscillator either, so used an RC one instead.
>
> I tried emailing Westinghouse about this and they fobbed me off to a
> subsidiary who couldn't even bother to respond to an email.
>
> Thanks for reading. Anyone got any other ideas about why the stupid
> clock in this microwave loses time?
>
> Jeff
>
> --
> Jeffry Wisnia
> (W1BSV + Brass Rat '57 EE)
> The speed of light is 1.8*10e12 furlongs per fortnight.

Donate it...and buy a new one. I've never had an appliance with a
digital clock that kept poor time. Coffee maker, oven/range, MW, or
VCR.

== 5 of 8 ==
Date: Sat, Apr 23 2011 6:38 am
From: Bill Gill

On 4/23/2011 7:05 AM, William Sommerwerck wrote:
> "David Nebenzahl"<nobody@but.us.chickens> wrote in message
> news:4db28ccc$0$10024$822641b3@news.adtechcomputers.com...
>
>> My Magic Chef, which I got used, lessee, 23 years ago
>> or so and still works perfectly, has a very accurate clock.
>> Crystal-controlled, I'm going to guess.
>
> In the US, line frequency used to be (and probably still is) "tweaked" so
> that clocks with synchronous motors would have zero net error over a long
> period of time. This should give better accuracy than a crystal.
>
>
Correct. In fact back in the early 70s when they had the big
power outage in the NorthEast US my sister was working at a
radio station that checked their electric clock against WWV
every day. When the blackout occurred their clock lost a bunch
of time (I don't remember exactly how much) due to the load
slowing down all of the generators. They reset it and then for
the next week or more they had to set it back every day as the
mains frequency was cranked up a bit until the long term
frequency was returned to 60 Hz. In fact it was for a long
time known that long term stability of the 60 Hz power was
some of the best available. Short term was never as good, it
tended to cycle up and down a bit according to various things
happening.

Bill

== 6 of 8 ==
Date: Sat, Apr 23 2011 6:49 am
From: "Phil Allison"

"John Tserkezis is a Tserk "

> Regardless, locking your clock to mains is not always a great idea.
> Some areas are just plain wrong. I have a mains locked clock here that
> loses a minute every week or so.

** This fucking, retarded fuckwit has just gotta be totally INSANE !!

The fool has NO IDEA what an energy " supply grid " even is.

Hint - all the alternators are LOCKED IN PHASE all of the time.

No magic - no alternative is even possible for them.

.... Phil

== 7 of 8 ==
Date: Sat, Apr 23 2011 7:41 am
From: stratus46@yahoo.com

On Apr 22, 10:27 pm, John Tserkezis
<j...@techniciansyndrome.org.invalid> wrote:
> jeff_wisnia wrote:
> > I'm shocked, shocked, that the clock isn't synced to the 120 volt 60 Hz
> > power the unit runs on, like every other line powered appliance with a
> > digital TOD display I own.
> > The only reason I can guess for the poor timekeeping is that the
> > circuitry/board running the clock is used on their 220 volt 50 Hz
> > versions without modification, so the makers decided not to use line
> > sync for the clock, and probably didn't want to spring for a crystal
> > oscillator either, so used an RC one instead.
>
>  I don't think this is a 50/60Hz issue.  From the error rate you
> describe, it should run faster not slower, and by a larger margin too.
>
>  Regardless, locking your clock to mains is not always a great idea.
> Some areas are just plain wrong.  I have a mains locked clock here that
> loses a minute every week or so.
>  I have cheap non temperature compensated crystal locked clocks that are
> by far superior to that.
>
>  The answer is worse than that.
>
>  The clocks are built to a price, the cheapest possible price.
>
>  Consider this: A microwave oven doesn't need a clock at all, just a
> timekeeper for timed cooking.  Accuracy is not a priority here at all.
>  The fact they have clocks at all means the manufacturers wanted to get
> one leg up on the competitors without expending any money.
>
>  We're not talking cameras in cellphones here, there is NO reason for
> them to make their clocks accurate, because non of the competition are
> going to bother either.
> --
> To err is human. To moo bovine

So you live in a place _not_ on the grid?

G²

== 8 of 8 ==
Date: Sat, Apr 23 2011 8:02 am
From: news@jecarter.us

On Fri, 22 Apr 2011 13:35:47 -0400, jeff_wisnia
<jwisniaDumpThisPart@conversent.net> wrote:

>
> From my "I can't believe they'd make it this way" list.
>
>Last year I purchased a new Westinghouse Model WST-3501 microwave oven
>for our office lunchroom.
>
>It heats and cooks things fine, but has one lousy feature which I can't
>avoid noticing and which irks me very time I see it.
>
>The TOD, which is displayed whenever the unit is on standby, loses about
>two minutes a day, and has to be reset every few days to keep from
>falling ridiculously behind.
>
[snip]
>
>Jeff

I have a small coffee maker that has never kept good time. My guess
is that *any* noise on the AC line affects the pulse counting. I have
a weather station whose clock is synced to NIST, so no longer bother
to set the clock on the coffee maker.

John

==============================================================================
TOPIC: Lead free solder
http://groups.google.com/group/sci.electronics.repair/t/7ff46ef49e9b7de3?hl=en
==============================================================================

== 1 of 12 ==
Date: Sat, Apr 23 2011 12:51 am
From: adrian@poppyrecords.invalid.invalid (Adrian Tuddenham)

who where <noone@home.net> wrote:

> On Thu, 21 Apr 2011 17:07:11 -0400, "Charles"
> <charlesschuler@comcast.net> wrote:
>
> >Has this had any impact on repair and rework of electronic devices and
> >equipment?
>
> Of course. The increased number of failures due solely to solder
> joints has kept many a service department busy. Reworking with
> "decent" solder is the simplest treatment.

Not in Europe it isn't. There are heavy fines for doing that.

--
~ Adrian Tuddenham ~
(Remove the ".invalid"s and add ".co.uk" to reply)
www.poppyrecords.co.uk

== 2 of 12 ==
Date: Sat, Apr 23 2011 12:57 am
From: "Phil Allison"

"Adrian Tuddenham"

>> Of course. The increased number of failures due solely to solder
>> joints has kept many a service department busy. Reworking with
>> "decent" solder is the simplest treatment.
>
> Not in Europe it isn't. There are heavy fines for doing that.

** The fines may exist in theory, but can you show if anyone has been fined
for using the wrong solder for repairs ?

There are many obvious, simple defences to such a charge and almost no way
to get caught.

Get real.

..... Phil

== 3 of 12 ==
Date: Sat, Apr 23 2011 1:08 am
From: "N_Cook"

Adrian Tuddenham <adrian@poppyrecords.invalid.invalid> wrote in message
news:1k065wl.1q7rnpr1tk23cuN%adrian@poppyrecords.invalid.invalid...
> who where <noone@home.net> wrote:
>
> > On Thu, 21 Apr 2011 17:07:11 -0400, "Charles"
> > <charlesschuler@comcast.net> wrote:
> >
> > >Has this had any impact on repair and rework of electronic devices and
> > >equipment?
> >
> > Of course. The increased number of failures due solely to solder
> > joints has kept many a service department busy. Reworking with
> > "decent" solder is the simplest treatment.
>
> Not in Europe it isn't. There are heavy fines for doing that.
>
> --
> ~ Adrian Tuddenham ~
> (Remove the ".invalid"s and add ".co.uk" to reply)
> www.poppyrecords.co.uk

For the UK, section 14 of the RoHS Regulation

A producer putting non-compliant EEE on the market on or after 1st July 2006
shall be liable on summary conviction to a fine not exceeding the statutory
maximum, which the Home Office says is currently �5,000. Or "on conviction
on indictment to fine" - there is no statutory maximum.

Producers failing to provide documents showing compliance within 28 days of
an official request shall be liable on summary conviction to a fine not
exceeding level 5 on the standard scale. Level 5, coincidentally, is also
�5,000 at the moment.

Failing to retain technical documentation for four years after EEE has been
put on the market is also a not-exceeding-level-5 fine.

EEE= electrical and electronic equipment

== 4 of 12 ==
Date: Sat, Apr 23 2011 2:40 am
From: "Phil Allison"

"Nutcase Kook is a FUCKWIT "

>>
>> Not in Europe it isn't. There are heavy fines for doing that.
>>
>
>
> For the UK, section 14 of the RoHS Regulation
>
>
> A producer putting non-compliant EEE on the market ...

** WTF has that got to do with the QUESTION' ???

You fucking imbecile ...

.... Phil

== 5 of 12 ==
Date: Sat, Apr 23 2011 3:02 am
From: "Arfa Daily"

"Phil Allison" <phil_a@tpg.com.au> wrote in message
news:91f97mFs4uU1@mid.individual.net...
> "Arfa Daily"
>
>>> I don't know whereabouts in the world you
>>> are, but across Europe, strictly speaking, it is actually illegal to use
>>> leaded solder, or non RoHS components, to repair anything manufactured
>>> in
>>> lead-free after implementation of the RoHS directive, which was June
>>> 2006 (I
>>> think) in the UK.
>>
>> I think that's one of mine ...
>
>
> ** Find me one example of a person being successfully prosecuted over it.

Did I say that there was ? No.

>
> There is virtually no way to get caught, no easy way for outsiders to know
> and nobody gives a shit.

Nor did I say otherwise, but that doesn't mean that it isn't a possibility,
or that I am stating anything other than the facts. Look up the meaning of
your own word - "virtually". I suppose the poor bastard who got thrown in
prison here for selling his bananas by the pound instead of the kilo thought
the same thing. And if you don't know of that in Ozland, look up Steve
Thoburn. The fact of the matter is that it *is* illegal within the EU under
the terms of the directive, to carry out repairs to RoHS certified equipment
manufactured after June 2006 and using RoHS certified components and
lead-free solder, with anything other than RoHS certified components and
lead-free solder. None of us like it. All of us think it is stupid. But none
of that changes the facts. Nor does you running off at the mouth in your
usual way about how big and brave you are and don't give a shit. The *real*
fact of the matter is that you never know just who's spying on you via the
'net these days, and if one of the ecobollox EU people found someone on here
from the EU telling all how they also "don't give a shit", then you might
just finish up having your example of someone successfully prosecuted ... As
you don't live in the EU, you know nothing of the levels of bureaucracy and
petty mindedness of these officials.

Arfa

>
>
>
> .... Phil
>
>
>
>

== 6 of 12 ==
Date: Sat, Apr 23 2011 4:03 am
From: "Phil Allison"

"WangoTango"
>
> Depends on where you are and if the device is yours or not.
> Here in the US we can use real solder that really works, so no issue.
> If you live where lead free is a commercial reality, who is going to
> know if you use good old 60/40 (63/37) to fix your own stuff?

** Who is likely to ever know or care a hoot if it is not your own stuff ??

The only people who KNOW for sure if some product has Pb free solder in some
or all locations is the bastards who made it. And none of them are traceable
years after it is sold.

I mean the ACTUAL people - in China or wherever.

A product may be legitimately labelled " RoHS Compliant " though full of
leaded solder - cos it complies by exemption.

Marshall Amplification applied and got an exemption for the use of CdS cells
in their amps (even a few micrograms of Cadmium is verboten) - how
fucking absurd.

Strangely, Fender have obtained no such exemption are forced to no longer
use such cells in amps sold into Europe.

An elaborate PCB, fitted with numerous IC is fitted to TUBE amplifiers to
comply.

How fucking ABSURD !!

> I've reworked many lead free boards with lead solder, and we use 100's
> of thousands of ROHS parts with good old 63/37.

** Same here.

..... Phil

== 7 of 12 ==
Date: Sat, Apr 23 2011 5:09 am
From: "William Sommerwerck"

>> Of course. The increased number of failures due solely
>> to solder joints has kept many a service department busy.
>> Reworking with "decent" solder is the simplest treatment.

> Not in Europe it isn't. There are heavy fines for doing that.

How would the government know? Are there solder Nazis breaking into service
shops, looking for rolls of illicit lead-based solder?

I hate callbacks. I would use lead-based solder on repairs.

== 8 of 12 ==
Date: Sat, Apr 23 2011 5:12 am
From: "William Sommerwerck"

> Marshall Amplification applied and got an exemption for the
> use of CdS cells in their amps (even a few micrograms of
> cadmium is verboten) -- how fucking absurd.

Oh... my... God... I didn't know I was poisoning my subjects when I took
pictures of them with my classic Polaroid Colorpack cameras.

== 9 of 12 ==
Date: Sat, Apr 23 2011 5:37 am
From: "Ian Field"

"Charles" <charlesschuler@comcast.net> wrote in message
news:ioq69t$9qt$1@dont-email.me...
> Has this had any impact on repair and rework of electronic devices and
> equipment?

RoHS is an evil plot to do something - but its not clear exactly what!!!

The result out in the field is that electronic equipment is much less
reliable and has a maximum life expectancy of around a couple of years.

Since the now 5x (or more!) as much electronics scrap is no longer permitted
in landfill, it gets dumped on third world countries for slum dwellers to
pick over mounds of the stuff for recyclable materials.

== 10 of 12 ==
Date: Sat, Apr 23 2011 5:38 am
From: "Phil Allison"

"William Sommerwerck"
>
>>> Of course. The increased number of failures due solely
>>> to solder joints has kept many a service department busy.
>>> Reworking with "decent" solder is the simplest treatment.
>
>> Not in Europe it isn't. There are heavy fines for doing that.
>
> How would the government know? Are there solder Nazis breaking into
> service
> shops, looking for rolls of illicit lead-based solder?
>
> I hate callbacks. I would use lead-based solder on repairs.

** For once, the Sommerwanker posts something quite sensible.

Maybe there is still hope ...

... Phil

== 11 of 12 ==
Date: Sat, Apr 23 2011 5:47 am
From: "Ian Field"

"Phil Allison" <phil_a@tpg.com.au> wrote in message
news:91f91aFqomU1@mid.individual.net...
>
> "mike the moron "
>>>
>>> Standard procedure round here is to remove it with wick and use some
>>> real
>>>>> 60/40 Savbit solder to make the repair.
>>>>>
>>>> Arent't there some legal issues with that?
>>>
>>>
>>> **You tell us - fuckhead
>>>
>>> But round here = Australia where the RoHS directive is not law.
>>>
>>> Nor is it law in Japan, North America and most places.
>>>
>>> And I would not give a shit if it was.

Since RoHS, the WEEE directive has passed into law meaning that scrap
electronics are not permitted in landfill and have to be shredded for
recovery of recycleable materials, in theory this means that lead, Cd or
anything else is irrelevant.

In practice, lead free solder reliability issues result in such huge volumes
of scrap that it gets dumped on third world countries for slum dwellers to
pick over for recoverable metals.

== 12 of 12 ==
Date: Sat, Apr 23 2011 8:22 am
From: Smitty Two

In article <91f8mjFosbU1@mid.individual.net>,
"Phil Allison" <phil_a@tpg.com.au> wrote:

> " Meat Plow is a MORONIC FUCKHEAD "
>
>
> ** The simple truth.
>
>
>
>
> .... Phil

Wow, Meat, you can predict the future! How about giving me this week's
winning lottery numbers?

==============================================================================
TOPIC: Really "need to" replace older CATV cables? Would my cable provider
really filter my line against my will?
http://groups.google.com/group/sci.electronics.repair/t/31e43b6766887486?hl=en
==============================================================================

== 1 of 2 ==
Date: Sat, Apr 23 2011 2:04 am
From: Jeff Urban

The problem could be standing waves. I don't think any FSM is accurate
enough to detect that. First of all the cable modem requires a
specific frequency, but it also requires the sidebands. In some cases
standing waves can cause complete eradication of 400,0001 Mhz yet
barely affect 400.0002 and 400.0000 Mhz. If this happens the signal
strength is fine bit there is so much distortion in the modulation
that the signal is near unusable.

Remember reorienting the antenna to get rid of ghosts in a TV picture
or distortion in an FM signal ? It is the same thing. Standing waves
are very much like multipath in their effects on signal quality. Some
old FM tuners actually had a scope built in to display multipath. The
optimum signal would display pretty much a flat line. Moving the
antenna would cause dips in the line, and that is what causes
distortion. Measuring signal strength just doesn't cut it.

He may have been blowing smoke about the TVs polluting the signal.
It's hard to believe the effect would be a big problem if they meet
FCC requirements on radiation. But then it's possible that he was just
attempting to improve the signal as much as possible. Hard to say. I
know people get alot of lip service when what they want is service,
this one is tough to call either way. Maybe he just did what he
could.

But FCC requirements say nothing about antenna input impedance, if
that is off it can cause the standing waves. I'm not sure if a filter
would take care of that completely. It seems it should but I know
better, things do not always work as they are supposed to.

If you are talking a "thinner" cable than what is used tody it is
probably RG59 or RG59U, both of which attenuate the high frequencies
significantly. If the cables and the fittings are perfect this is
simply due to capacitance and is not likely to cause standing waves.
But then those things are not likely to be perfect, and may not have
been in the beginning.

The only way to tell really is with a sweep spectrum analyser, and
those things will not be on the truck due to cost. The cables could
also be checked for that using a time domain reflectometer, which
would be even better, but look up the cost of one and you'll see why
there was not one on the truck. It's simply too expensive.

It is possible that it is the cables, and you don't need a licensed
electrician for that in most localities because there is no power
involved. But finding someone who really knows how to hide the wires
is not easy. Most higher caliber electricians can do it but they
usually simply refuse because it is a ballbuster. I can do it, but
unles you live nearby it is not going to happen.

Do your neighbors have this problem ? If not get them to run a line
straight into your existing cables and see if the problem persists. It
will have to be attenuated to the same level you have now to make it a
valid test. If it is found to be in the wiring in your unit, which can
only be proven by others in the same complex using the same modem,
with a couple of other requirements, it may be a matter of fishing a
new cable into wherever it splits off into your unit. It is very hard
to be absolutely sure, and the shotgun approach may be a better idea -
which is to replace all the cables in your unit.

Now is another factor, there is more than one carrier frequency
involved in cable internet distribution. These two modems might work
on different frequencies, and due to the nature of the effect of
standing waves that can make all the difference in the world. So now
the question is, since they got you hooked up with the other modem,
why not just leave it that way ? Is there a rational explainaition for
that ? They may have reasons we may never know, but it seems to me if
they want that check every month they should do whatevwer it takes.

So my highly technical ass with all the experience has this advice -
Tell them to take their service and shove it up where, well make sure
it doesn't get a sunburn. Tell them the wires are fine with the old
modem, why change it ? Tell them you are considering other options and
since they can't provide what you are paying for the contract is null
and void - they are in breach. You should see some action.

See to them it's not just the monthly check, it's market share.
Therefore threatening to quit works wonders. Got someone I know a free
wireless router a few months ago, but she is sharp. Not when it comes
to computers, but when it comes to money. She was head of the
purchasing department before she retired and she gets things done.
Threatening to do business elsewhere has alot more impact to companies
like this than one might think. Having more customers does alot, it
can affect stock prices, the D&B rating as well as their advetising
plans. Use it against them if they don't deliver the goods.

J

== 2 of 2 ==
Date: Sat, Apr 23 2011 5:16 am
From: "William Sommerwerck"

"Jeff Urban" <jurb6006@gmail.com> wrote in message
news:7ebf4686-9c26-4ff5-b044-424c2bf0c885@j25g2000vbr.googlegroups.com...

> The problem could be standing waves. I don't think any FSM is
> accurate enough to detect that. First of all the cable modem requires a
> specific frequency, but it also requires the sidebands. In some cases
> standing waves can cause complete eradication of 400,0001 Mhz yet
> barely affect 400.0002 and 400.0000 Mhz. If this happens the signal
> strength is fine bit there is so much distortion in the modulation
> that the signal is near unusable.

I don't think you know what you're talking about. Interference effects
generally vary continuously -- they do not occur at one frequency, then
miraculously disappear at another.

Given the age of the cable, it's possible it's deteriorated to the point
where it needs replacement. I was reading something recently -- possibly in
this group -- about the way the outer plastic insulation can actually
"attack" coax dielectric. Or something like that.

==============================================================================
TOPIC: Toshiba Satellite Pro M15-S405 PCB flux rot
http://groups.google.com/group/sci.electronics.repair/t/5f474e30d60254b9?hl=en
==============================================================================

== 1 of 1 ==
Date: Sat, Apr 23 2011 2:43 am
From: "Uffe Bærentsen"

"Jeff Liebermann" <jeffl@cruzio.com> skrev i en meddelelse
news:ia34r69f6ol7inagablvvbgc315bivc7ii@4ax.com...
> Here's one I haven't seen before:
> <http://802.11junk.com/jeffl/crud/toshiba-rot-02.jpg>
> It's the motherboard from a Toshiba Satellite Pro M15-S405 laptop. The
> brown crud is probably flux left over from the soldering operation or
> something corrosive, that was trapped between the PCB and a thin
> plastic "protective" covering under the DVD drive. The board acts
> totally dead. No power, no charge lite, no sounds, no nothing. At
> first, I thought that someone had spilled some liquid into the laptop.
> Nope, because all the corrosion is BETWEEN the PCB and the plastic,
> with nothing on top of the plastic. The plastic covering was totally
> clean. There's no corrosion in the area that's NOT under the
> "protective" covering, so it seems whatever did the damage, was
> volatile.
>
> The customer has 3 other identical laptops. I just inspected them
> (through the DVD slot), and found no corrosion.
>
> I'm not sure I'll be able to fix this one as the rotted traces in this
> area are very tiny. It's probably not worth the effort for a 9 year
> old laptop.

From what I can see the PCB is flipped over (upside down).
Liquid (cola?) might have landed on the top surface and then it is wicked
through the PCB through the via's to the bottom side where it gets trapped
in between the PCB and the plastic covering.
Have seen almost the same with a Logitech keyboard.
The liquid that landed on the top surface was free to evaporate.
The liquid on the bottom surface was trapped and could etch away :-(

--
Uffe Bærentsen

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TOPIC: Denon DN-A7100 surround preamp
http://groups.google.com/group/sci.electronics.repair/t/11d516c552e831ed?hl=en
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== 1 of 1 ==
Date: Sat, Apr 23 2011 3:22 am
From: "Mark Zacharias"

"Tim Schwartz" <tim@bristolnj.com> wrote in message
news:iotbgl$8b1$1@dont-email.me...
> Hello all,
>
> I've got a Denon DN-A7100 which came in with a complaint of the front
> panel volume control (rotary encoder) not working, but volume on the
> remote OK. I initially traced it don to no +5V on the encoder when, OH
> JOY, it fixed itself.
>
> Anyone seen this problem on this model before? Anyone have an e-mailable
> schematic?
>
> Thanks!
> Tim Schwartz
> Bristol Electronics

It'll be the volume encoder - I get these sorts of complaints all the time.
You can 'scope the output and see how noisy or nearly non-existent it is.

Part number is 9430205909

I stock your most common types for this reason. It so happens that Onkyo
sells them cheap. Send me a pic and the dimensions and I'll bet I have one.

Mark Z.

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TOPIC: 42" Panasonic plasma TV model: TH-42PX60U dead
http://groups.google.com/group/sci.electronics.repair/t/c8e947a6771af994?hl=en
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== 1 of 1 ==
Date: Sat, Apr 23 2011 3:34 am
From: "Mark Zacharias"

"N_Cook" <diverse@tcp.co.uk> wrote in message
news:iotvpg$dq$1@dont-email.me...
> Sidney <sidneybek@yahoo.com> wrote in message
> news:27a07052-b46d-4014-a154-f6e827f81265@a19g2000prj.googlegroups.com...
> 42" Panasonic plasma TV model: TH-42PX60U, year: Nov 2006, no power,
> no blinking or standby LED lights. The TV was on while this happened.
> Upon troubleshooting I discovered F401=8 amp ceramic time lag fuse to
> be open. From extensive googling after no obvious shorts in power
> supply using Fluke DMM model 29 series II. I found the following
> common repair tips:
>
> Q406=N-ch MOSFET # RJK5020=Panasonic # B1DEKQ000003=shorted
> R410=10 ohm, 5w ceramic thermal cut off=Panasonic # D1F5100E0003=open
> F401 & F402=8 amp ceramic time lag fuse= Panasonic # K5D802BNA005= one
> or the other open
>
> well on this TV none of the above parts are defective except F401.
> According to a Panasonic service bulletin for a similar model:
>
> http://www.tvrepairtips.org/files/tip/286/tt-08-27.pdf
>
> they say to add a C426=ECQB1H103JZ but on that bulletin it's if Q406
> is shorted but not on mine and the board on the service bulletin is
> somewhat different than mine. I haven't yet replaced F401 or placed a
> 100 watt light bulb in place. But would like some tips before I
> proceed. Thanks.
>
> Sidney� �
> Dartmouth, Nova Scotia
> Canada
>
> http://web.archive.org/web/20040312120415/www.herald.ns.ca/cgi-bin/home/disp
> layphoto?2002/12/22+126.raw+1019+Business+
>
> http://web.archive.org/web/20040229023255/http://www.herald.ns.ca/cgi-bin/ho
> me/displaystory?2002/12/22+126.raw+Business
>
> http://groups.google.com/group/hfx.forsale/browse_thread/thread/43940ce83231
> ab85/4e4c696fbf04837f?q=sidney+tv+repair&rnum=1#4e4c696fbf04837f
>
> http://www.nesda-ohio.com/iwaynet/pubhtml/May02/May18.html
> http://www.nesda-ohio.com/iwaynet/pubhtml/SonyAudMod.html
> http://www.nesda-ohio.com/iwaynet/pubhtml/Oct02/Oct028.html
> http://www.nesda-ohio.com/iwaynet/pubhtml/Oct02/Oct029.html
>
>
>
> ++++
>
>
> open up the fuse and see if it failed gently (probably just getting tired
> in
> old age) or catastrophically so something else failing caused it to fail
>
>
>

I have seen some Samsung models on which the fuse goes for no reason other
than the fuse holder is defective - not rated for high enough amperage. The
fuses are GMA size ceramic types. The holders in question are ordinary
looking except they have a sort of black plastic case in which the actual
metal holders are nestled.. There was obvious overheating - a discolored and
crusty appearance to the metal, and the plastic was deformed sometimes even
to the point of melting somewhat. A fuse should never get hot like that - it
was the ohmic resistance between the holder and the fuse ends. A brand new
supply from Samsung failed the same way within days. A solder-in pigtail
type fuse solved the problem for good.

Mark Z.

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TOPIC: A specific PCB bad practise, term for it ?
http://groups.google.com/group/sci.electronics.repair/t/8689adb4b80bfe29?hl=en
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== 1 of 1 ==
Date: Sat, Apr 23 2011 8:24 am
From: "N_Cook"

Where holes are drilled for thru-board components but of diameter far too
big , thru-hole plated , but no eyelet/inserts used to fill the gap. So
1N4001 size leads in holes twice their diameter and 1N4148 in holes twice
their diameter. So not a case of only one drill size for all. So in area
terms about 1 to 4 ratio of lead to solder. Bad enough practise with proper
solder but with PbF, ring cracks starting all over.
Is it to avoid mutiny by the by-hand board populators ?

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