sci.electronics.repair - 25 new messages in 8 topics - digest

sci.electronics.repair
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Today's topics:

==============================================================================
TOPIC: DTV sound synch
http://groups.google.com/group/sci.electronics.repair/t/2896d12048fef530?hl=en
==============================================================================

== 1 of 10 ==
Date: Sat, Jan 29 2011 12:39 am
From: "N_Cook"

David Nebenzahl <nobody@but.us.chickens> wrote in message
news:4d439097$0$23162$822641b3@news.adtechcomputers.com...
> Question is about DTV sound synchronization in the United States (the
> only DTV I have any experience of). Seems to me that since it replaced
> analog, the synchronization of sound to picture is, at best, variable,
> and sometimes it's absolutely piss-poor.
>
> Watching some programming, like a classical music performance where one
> can see string players' bows moving, sometimes the sound is so far off
> as to be quite irritating, seemingly as much as half a second or so.
>
> I don't know enough about DTV to say why this would be so, and whether
> the problem is with the station originating the broadcast or somewhere
> else along the line. (I'm guessing this problem doesn't occur at the
> receiver end.) Anyone else notice this?
>
>
> --
> Comment on quaint Usenet customs, from Usenet:
>
> To me, the *plonk...* reminds me of the old man at the public hearing
> who stands to make his point, then removes his hearing aid as a sign
> that he is not going to hear any rebuttals.

Even on , supposed, live feeds , often lack of sync in the UK
You mention classical music. I cannot listen to proper music on any of the
UK freeview channels because of some sort of overload distortion. This is
same on 2 makes of set-top box , is it just Rowridge, IoW, transmissions/
local multipath problem to me or do others find this issue in the UK? Is
there a name for this distortion ? full orchestra with the brakes on is fine
but go forte and clipping sort of compression distortion - if only they
still had test-cards with pilot tone these days, so I could scope.
And also related, no time signals these days, no seconds of time mentioned
anywhere on digital.

== 2 of 10 ==
Date: Sat, Jan 29 2011 2:20 am
From: Adrian C

On 29/01/2011 08:39, N_Cook wrote:

> Even on , supposed, live feeds , often lack of sync in the UK
> You mention classical music. I cannot listen to proper music on any of the
> UK freeview channels because of some sort of overload distortion. This is
> same on 2 makes of set-top box , is it just Rowridge, IoW, transmissions/
> local multipath problem to me or do others find this issue in the UK? Is
> there a name for this distortion ? full orchestra with the brakes on is fine
> but go forte and clipping sort of compression distortion - if only they
> still had test-cards with pilot tone these days, so I could scope.
> And also related, no time signals these days, no seconds of time mentioned
> anywhere on digital.
>
There are some articles on http://www.audiomisc.co.uk that refer to
listening of classical music via DTT and issues, though my music
interest is mainly non-proper music containing mostly triangle waves,
but you may something of interest here.

Sound on Vision
<http://www.audiomisc.co.uk/HFN/SoV/soundonvision.html>

iPlayer rules OK?
<http://www.audiomisc.co.uk/BBC/iPlayerRulesOK/Page1.html>

--
Adrian C

== 3 of 10 ==
Date: Sat, Jan 29 2011 2:21 am
From: "Dave Plowman (News)"

In article <4d439097$0$23162$822641b3@news.adtechcomputers.com>,
David Nebenzahl <nobody@but.us.chickens> wrote:
> I don't know enough about DTV to say why this would be so, and whether
> the problem is with the station originating the broadcast or somewhere
> else along the line. (I'm guessing this problem doesn't occur at the
> receiver end.) Anyone else notice this?

I'm in the UK, but different receivers introduce their own differing
delay. As you'd notice with two on at the same time. And this is just DTV
tuners - not complete sets which may introduce a sound delay to compensate
for that in the display technology.

What I'm not sure is if the picture is still in sync with the sound on
these units.

There have been reports here of a re-boot sorting gross sound sync
problems on some makes.

--
*Sorry, I don't date outside my species.

Dave Plowman dave@davenoise.co.uk London SW
To e-mail, change noise into sound.

== 4 of 10 ==
Date: Sat, Jan 29 2011 2:28 am
From: "Dave Plowman (News)"

In article <ii0jml$dct$1@news.eternal-september.org>,
N_Cook <diverse@tcp.co.uk> wrote:
> You mention classical music. I cannot listen to proper music on any of
> the UK freeview channels because of some sort of overload distortion.
> This is same on 2 makes of set-top box , is it just Rowridge, IoW,
> transmissions/ local multipath problem to me or do others find this
> issue in the UK? Is there a name for this distortion ?

Must be a local to you thing. I only ever listen to TV sound through a
decent external sound system, and although there are sometimes problems,
it's not fundamental to the system. Indeed I use FreeView tuners for radio
these days.

One thing you could check is your not overloading the input to whatever
you're listening on - some STBs can supply much more output than analogue
ones, if things are peaked to 0dBFS.

--
*(on a baby-size shirt) "Party -- my crib -- two a.m

Dave Plowman dave@davenoise.co.uk London SW
To e-mail, change noise into sound.

== 5 of 10 ==
Date: Sat, Jan 29 2011 2:42 am
From: "N_Cook"

Dave Plowman (News) <dave@davenoise.co.uk> wrote in message
news:519d20e464dave@davenoise.co.uk...
> In article <4d439097$0$23162$822641b3@news.adtechcomputers.com>,
> David Nebenzahl <nobody@but.us.chickens> wrote:
> > I don't know enough about DTV to say why this would be so, and whether
> > the problem is with the station originating the broadcast or somewhere
> > else along the line. (I'm guessing this problem doesn't occur at the
> > receiver end.) Anyone else notice this?
>
> I'm in the UK, but different receivers introduce their own differing
> delay. As you'd notice with two on at the same time. And this is just DTV
> tuners - not complete sets which may introduce a sound delay to compensate
> for that in the display technology.
>
> What I'm not sure is if the picture is still in sync with the sound on
> these units.
>
> There have been reports here of a re-boot sorting gross sound sync
> problems on some makes.
>
> --
> *Sorry, I don't date outside my species.
>
> Dave Plowman dave@davenoise.co.uk London SW
> To e-mail, change noise into sound.

I use one most of the time and another to record another digital ch
concurrently off-air or for a second recorder on a few occassions. The
second one just feeds an earpiece so I can check the sound of that one
without any picture hook-up is the same as the main one with on-screen
ident, in case of r/c miskeyings. They never agree but they must each be in
sync within themselves , but not checked with 2 TVs simultaneously.

On the music distortion , there is a an UHF aerial amp in line, suppling
both set-top boxes. Sometime I will try a different one to see if it makes a
difference. Without an amp some channels become "no signal" although ok for
BBC4 , must try set-top box digital radio 3 sometime.

== 6 of 10 ==
Date: Sat, Jan 29 2011 2:55 am
From: "Dave Plowman (News)"

In article <ii0qum$3jj$1@news.eternal-september.org>,
N_Cook <diverse@tcp.co.uk> wrote:
> On the music distortion , there is a an UHF aerial amp in line, suppling
> both set-top boxes. Sometime I will try a different one to see if it
> makes a difference. Without an amp some channels become "no signal"
> although ok for BBC4 , must try set-top box digital radio 3 sometime.

I don't think anything you could do to the incoming RF data stream could
cause the problems you report. I'm in a very strong signal area as regards
UHF - I can see the Crystal Palace mast which is about 5 miles away. The
aerial fed direct to an analogue TV caused overload - but no such problems
when fed to a DTV box on trials. But of course I've not tried them all.

--
*I believe five out of four people have trouble with fractions. *

Dave Plowman dave@davenoise.co.uk London SW
To e-mail, change noise into sound.

== 7 of 10 ==
Date: Sat, Jan 29 2011 3:24 am
From: "N_Cook"

Dave Plowman (News) <dave@davenoise.co.uk> wrote in message
news:519d2408c2dave@davenoise.co.uk...
> In article <ii0qum$3jj$1@news.eternal-september.org>,
> N_Cook <diverse@tcp.co.uk> wrote:
> > On the music distortion , there is a an UHF aerial amp in line, suppling
> > both set-top boxes. Sometime I will try a different one to see if it
> > makes a difference. Without an amp some channels become "no signal"
> > although ok for BBC4 , must try set-top box digital radio 3 sometime.
>
> I don't think anything you could do to the incoming RF data stream could
> cause the problems you report. I'm in a very strong signal area as regards
> UHF - I can see the Crystal Palace mast which is about 5 miles away. The
> aerial fed direct to an analogue TV caused overload - but no such problems
> when fed to a DTV box on trials. But of course I've not tried them all.
>
> --
> *I believe five out of four people have trouble with fractions. *
>
> Dave Plowman dave@davenoise.co.uk London SW
> To e-mail, change noise into sound.

Its consistently the same , 2 different converters, 2 different aerials and
downleads.
So unlikely multipath problems which ttend th change with weather and time
of day etc. I think there is audio overload on general sound eg when there
is an argument, elevated voices and speaking at the same time - its just its
more obvious with an orchestra.

When I dig it out I will try another uhf amp, then it will be a full-on
mystery, if still the same audio problem. Never any picture problems other
than nearby motor use or very bad vehicle ignition

== 8 of 10 ==
Date: Sat, Jan 29 2011 3:36 am
From: Jeffrey Angus

On 1/29/2011 5:24 AM, N_Cook wrote:
> Its consistently the same , 2 different converters, 2 different aerials and
> downleads.
> So unlikely multipath problems which ttend th change with weather and time
> of day etc. I think there is audio overload on general sound eg when there
> is an argument, elevated voices and speaking at the same time - its just its
> more obvious with an orchestra.

Ya know, once upon a time, "Broadcast quality" used to mean
something.

Now it appears to mean, "How much advertising revenue can we
cram into something?"

Nobody gives a shit about "doing it right" all the way down the
line from the CEO to the techs.

Jeff

== 9 of 10 ==
Date: Sat, Jan 29 2011 7:38 am
From: Jamie

David Nebenzahl wrote:
> Question is about DTV sound synchronization in the United States (the
> only DTV I have any experience of). Seems to me that since it replaced
> analog, the synchronization of sound to picture is, at best, variable,
> and sometimes it's absolutely piss-poor.
>
> Watching some programming, like a classical music performance where one
> can see string players' bows moving, sometimes the sound is so far off
> as to be quite irritating, seemingly as much as half a second or so.
>
> I don't know enough about DTV to say why this would be so, and whether
> the problem is with the station originating the broadcast or somewhere
> else along the line. (I'm guessing this problem doesn't occur at the
> receiver end.) Anyone else notice this?
>
>
Yeah, a good plot to get rid of over the air TV all together. Just
think about all those extra cell phones they can add to the system and
make big money! ALong with all those other services that can be added
for a fee!

Jamie

== 10 of 10 ==
Date: Sat, Jan 29 2011 8:26 am
From: "Arfa Daily"

"Jeffrey Angus" <jangus@suddenlink.net> wrote in message
news:4d43fbab$0$5474$bbae4d71@news.suddenlink.net...
> On 1/29/2011 5:24 AM, N_Cook wrote:
>> Its consistently the same , 2 different converters, 2 different aerials
>> and
>> downleads.
>> So unlikely multipath problems which ttend th change with weather and
>> time
>> of day etc. I think there is audio overload on general sound eg when
>> there
>> is an argument, elevated voices and speaking at the same time - its just
>> its
>> more obvious with an orchestra.
>
> Ya know, once upon a time, "Broadcast quality" used to mean
> something.
>
> Now it appears to mean, "How much advertising revenue can we
> cram into something?"
>
> Nobody gives a shit about "doing it right" all the way down the
> line from the CEO to the techs.
>
> Jeff
>

I think to some extent, that depends on the 'quality' of the broadcaster
involved. I watch a lot of HD transmissions on sat, and most are superb.
I've never seen a sound / vision sync problem that I can remember. However,
I also watch some of the cheapo channels, and the whole production quality
can, as you say, be very variable. On these channels, I have often seen the
sync problem, so I guess that somewhere along the line, it's caused by cheap
production techniques, or maybe something to do with the bandwidth (cost) of
the data link from the programme producer to the uplink station, or maybe
the quality (cost) of the transponder that they are renting on the sat ?

Arfa

==============================================================================
TOPIC: Datasheet required STK795-820 or 821
http://groups.google.com/group/sci.electronics.repair/t/632acd16eeba7502?hl=en
==============================================================================

== 1 of 2 ==
Date: Sat, Jan 29 2011 3:09 am
From: Stroonz

On Jan 28, 9:32 pm, "Dave M" <dgminala4...@mediacombb.net> wrote:
> Stroonz wrote:
> > On Jan 28, 10:43 am, Fred <nob...@home.com> wrote:
> >> Stroonz <str00...@aol.com> wrote in news:50ee54ab-1903-4898-adcd-
> >> 0030de67d...@u14g2000vbg.googlegroups.com:
>
> >>> Can't find one anywhere, maybe not available. Any help appreciated.
>
> >> You need to learn aboutwww.google.com
>
> >> I put in STK795 data sheet and got over 16,000 hits. Take your pick.
>
> > And that helps me how? The STK795 series includes everything from
> > voltage regulators to IPMs. Anyone with knowledge of semiconductors
> > and hybrid ICs would know there are fundamental differences between
> > chopper regulators, amplifiers, IPMs, etc. I can't just "take my
> > pick". What I need is a datasheet for the STK795-820. The 821 is
> > functionally similar.
>
> Ummm... I think you missed the point. If you ask Google for exactly what
> you want, chances it will give it to you. Google for
>
> "STK795-820" datasheeet
>
> and you'll find it very quickly. Be sure to enclose the "STK795-820" within
> quotes, because the Google search engine interprets the dash as an exclusion
> term. That is, a dash in front of a word or character string will exclude
> that string from the search.
>
> Click on Advanced Search (on the Google search page) and your searches will
> be much more productive.
> --
> David
> dgminala at mediacombb dot net

Thanks Dave. I've done that. The problem is that although Google
returns hits that appear to be what I want, if you click on those
links they take you to places that sell the IPMs, but have NO actual
data sheet for that specific device, just the first one in the 795
series, which is a smps regulator IC. OTOH, it's possible I missed
the only link out of hundreds that might actually have it. Thanks
again.

Edwin

== 2 of 2 ==
Date: Sat, Jan 29 2011 8:29 am
From: "Arfa Daily"

"Stroonz" <str00ntz@aol.com> wrote in message
news:6b37ae72-21fc-41ec-9f8f-ca37c6475252@w19g2000yqa.googlegroups.com...
> On Jan 28, 9:32 pm, "Dave M" <dgminala4...@mediacombb.net> wrote:
>> Stroonz wrote:
>> > On Jan 28, 10:43 am, Fred <nob...@home.com> wrote:
>> >> Stroonz <str00...@aol.com> wrote in news:50ee54ab-1903-4898-adcd-
>> >> 0030de67d...@u14g2000vbg.googlegroups.com:
>>
>> >>> Can't find one anywhere, maybe not available. Any help appreciated.
>>
>> >> You need to learn aboutwww.google.com
>>
>> >> I put in STK795 data sheet and got over 16,000 hits. Take your pick.
>>
>> > And that helps me how? The STK795 series includes everything from
>> > voltage regulators to IPMs. Anyone with knowledge of semiconductors
>> > and hybrid ICs would know there are fundamental differences between
>> > chopper regulators, amplifiers, IPMs, etc. I can't just "take my
>> > pick". What I need is a datasheet for the STK795-820. The 821 is
>> > functionally similar.
>>
>> Ummm... I think you missed the point. If you ask Google for exactly
>> what
>> you want, chances it will give it to you. Google for
>>
>> "STK795-820" datasheeet
>>
>> and you'll find it very quickly. Be sure to enclose the "STK795-820"
>> within
>> quotes, because the Google search engine interprets the dash as an
>> exclusion
>> term. That is, a dash in front of a word or character string will
>> exclude
>> that string from the search.
>>
>> Click on Advanced Search (on the Google search page) and your searches
>> will
>> be much more productive.
>> --
>> David
>> dgminala at mediacombb dot net
>
> Thanks Dave. I've done that. The problem is that although Google
> returns hits that appear to be what I want, if you click on those
> links they take you to places that sell the IPMs, but have NO actual
> data sheet for that specific device, just the first one in the 795
> series, which is a smps regulator IC. OTOH, it's possible I missed
> the only link out of hundreds that might actually have it. Thanks
> again.
>
> Edwin

I don't think that you have. Clearly, you are an experienced searcher, and
your experience is exactly the same as mine on many occasions. Just for
sport, I followed your stk device all the way back to Sanyo's semicon site,
and although the device is basically recognised, it says that it is
obsolete, and no data is held on it, so I think that it is unlikely that you
will find any.

Arfa

==============================================================================
TOPIC: Laptop not charging.
http://groups.google.com/group/sci.electronics.repair/t/3f52116e8141f1a4?hl=en
==============================================================================

== 1 of 5 ==
Date: Sat, Jan 29 2011 4:24 am
From: T i m

Hi all,

I have asked elsewhere but I think this may be more an electronics
than computer question as such so:

A couple of years ago daughter b/f bought a Dell Inspiron 1545 laptop
and it has been running ok till just recently when his Mum caught the
power lead somehow.

From then on it still runs ok from the power adaptor / PSU but it
doesn't seem to want to charge the battery. What could be part of the
same issue is it now flashes the front power indicator with what looks
like 4 fast amber flashes and one longer white.

Going into the BIOS tells us that it thinks the battery is there and
'healthy' but is not charging and at 0%.

We tried another battery and psu from a different 1545 (that had a
broken DC socket) but that didn't change anything.

Yesterday, thinking it /could/ be a socket and where the tiny inner /
3rd pin connects (thinking it might be a 'sense' wire and a socket was
cheap etc) I changed it for him but again, no improvement.

I think it still runs from the battery but of course it's now flat
(coincidentally a mate is considering getting a Dell 1545 so we might
be able to do some tests <g>).

So, is there anything else we could do to try to work out what's going
on here please? I still have some test gear from my 'daze' as a
support tech (DMMs, scope, fc, bench PSU etc).

Cheers, T i m

== 2 of 5 ==
Date: Sat, Jan 29 2011 5:16 am
From: Ken

T i m wrote:
> Hi all,
>
> I have asked elsewhere but I think this may be more an electronics
> than computer question as such so:
>
> A couple of years ago daughter b/f bought a Dell Inspiron 1545 laptop
> and it has been running ok till just recently when his Mum caught the
> power lead somehow.
>
> From then on it still runs ok from the power adaptor / PSU but it
> doesn't seem to want to charge the battery. What could be part of the
> same issue is it now flashes the front power indicator with what looks
> like 4 fast amber flashes and one longer white.
>
> Going into the BIOS tells us that it thinks the battery is there and
> 'healthy' but is not charging and at 0%.
>
> We tried another battery and psu from a different 1545 (that had a
> broken DC socket) but that didn't change anything.
>
> Yesterday, thinking it /could/ be a socket and where the tiny inner /
> 3rd pin connects (thinking it might be a 'sense' wire and a socket was
> cheap etc) I changed it for him but again, no improvement.
>
> I think it still runs from the battery but of course it's now flat
> (coincidentally a mate is considering getting a Dell 1545 so we might
> be able to do some tests<g>).
>
> So, is there anything else we could do to try to work out what's going
> on here please? I still have some test gear from my 'daze' as a
> support tech (DMMs, scope, fc, bench PSU etc).
>
> Cheers, T i m
>
>
>

I encountered the same symptoms with a Toshiba Satellite laptop my son
had. Your problem might be totally unrelated, but here is what I found:
Toshiba had a problem with the connector they used for the external PS
coming loose on the mother board. Soldering or repairing that connector
did NOT solve all the problems, as like your computer, it would run from
the PS but not charge the battery. It seems my son (knowing nothing
about electronic repair) thought it would be useful to push something
into the case in the area of the power connector, and unknowingly
damaged a surface mounted transistor. I measured the voltages at the
damaged SMD and determined that it needed to be an NPN and what it
needed to withstand voltage and current wise. When I replaced the
transistor it worked fine.

As I said above, your problem might be totally unrelated, but you might
look for any damaged components in the vicinity of the power connector.
Quite a coincidence that the symptoms are identical.

== 3 of 5 ==
Date: Sat, Jan 29 2011 5:25 am
From: T i m

On Sat, 29 Jan 2011 07:16:35 -0600, Ken <Ken@invalid.com> wrote:

> I encountered the same symptoms with a Toshiba Satellite laptop my son
>had. Your problem might be totally unrelated, but here is what I found:

Ok and thanks for the reply ..

> Toshiba had a problem with the connector they used for the external PS
>coming loose on the mother board. Soldering or repairing that connector
>did NOT solve all the problems, as like your computer, it would run from
>the PS but not charge the battery.

Ok.

> It seems my son (knowing nothing
>about electronic repair) thought it would be useful to push something
>into the case in the area of the power connector, and unknowingly
>damaged a surface mounted transistor.

Ah. ;-(

> I measured the voltages at the
>damaged SMD and determined that it needed to be an NPN and what it
>needed to withstand voltage and current wise.

Nice to be old enough to remember and know how to deal with
transistors, SM or otherwise eh. ;-)

> When I replaced the
>transistor it worked fine.

Hmm, I don't think there has been any 'tampering' in this case however
these is a (20 pin) ship on the same daughter board that carries the
power socket (and Ethernet and a couple of USBs). I did inspect the
board for any sign of damage but there was none. However, because it
/is/ on a daughter board it would be possible to swap it to at least
see if it were that rather than the system board etc.
>
> As I said above, your problem might be totally unrelated, but you might
>look for any damaged components in the vicinity of the power connector.
> Quite a coincidence that the symptoms are identical.

Indeed.

I would like to think this led flashing sequence actually indicated
'the fault' or at least if it wasn't a formal message that someone
might recognise what it may indicated and give us an idea if it a
feasible repair or something he just lives with (not sure how often it
needs battery power as such bit it would be nice to have (back) in any
case.

All the best,

T i m

== 4 of 5 ==
Date: Sat, Jan 29 2011 5:50 am
From: Adrian C

On 29/01/2011 12:24, T i m wrote:
> So, is there anything else we could do to try to work out what's going
> on here please? I still have some test gear from my 'daze' as a
> support tech (DMMs, scope, fc, bench PSU etc).

There is a vietnamese web forum that has full schematics for many laptops.

Paste the following into google

site:kythuatvitinh.com inspiron 1545

You'll have to join the forum to download taking care to practice 'safe
hex' with documents you may get.

--
Adrian C

== 5 of 5 ==
Date: Sat, Jan 29 2011 6:04 am
From: Ken

T i m wrote:
> On Sat, 29 Jan 2011 07:16:35 -0600, Ken<Ken@invalid.com> wrote:
>
>
>> I encountered the same symptoms with a Toshiba Satellite laptop my son
>> had. Your problem might be totally unrelated, but here is what I found:
>
> Ok and thanks for the reply ..
>
>> Toshiba had a problem with the connector they used for the external PS
>> coming loose on the mother board. Soldering or repairing that connector
>> did NOT solve all the problems, as like your computer, it would run from
>> the PS but not charge the battery.
>
> Ok.
>
>> It seems my son (knowing nothing
>> about electronic repair) thought it would be useful to push something
>> into the case in the area of the power connector, and unknowingly
>> damaged a surface mounted transistor.
>
> Ah. ;-(
>
>> I measured the voltages at the
>> damaged SMD and determined that it needed to be an NPN and what it
>> needed to withstand voltage and current wise.
>
> Nice to be old enough to remember and know how to deal with
> transistors, SM or otherwise eh. ;-)
>
>> When I replaced the
>> transistor it worked fine.
>
> Hmm, I don't think there has been any 'tampering' in this case however
> these is a (20 pin) ship on the same daughter board that carries the
> power socket (and Ethernet and a couple of USBs). I did inspect the
> board for any sign of damage but there was none. However, because it
> /is/ on a daughter board it would be possible to swap it to at least
> see if it were that rather than the system board etc.
>>
>> As I said above, your problem might be totally unrelated, but you might
>> look for any damaged components in the vicinity of the power connector.
>> Quite a coincidence that the symptoms are identical.
>
> Indeed.
>
> I would like to think this led flashing sequence actually indicated
> 'the fault' or at least if it wasn't a formal message that someone
> might recognise what it may indicated and give us an idea if it a
> feasible repair or something he just lives with (not sure how often it
> needs battery power as such bit it would be nice to have (back) in any
> case.
>
> All the best,
>
> T i m
>

I see you have a reply that directs you to a website for a schematic.
That might be useful. But not having worked on your computer or one
like it before, here is what I would do:

If the trouble began when the PS lead was pulled, it is possible that
too high a voltage might have been applied if there is a feedback lead
for the PS and it was broken. That might have applied too great a
voltage to the laptop. This is just theory you understand.

I would plug in a known good PS and with a DVM measure both ends of
components near the connector. Look especially close for low value
resistors or anything that might be a SM fuse. If too great a voltage
were applied you might have opened a component and that is why a good PS
still does not work. Also look at the daughter board if it is attached
with a connector to the mother board. A tug on the power connector
might have caused a poor connection where the daughter board meets the MB.

==============================================================================
TOPIC: EARN 1000 DOLLARS PER DAY - WITHOUT INVESTMENT
http://groups.google.com/group/sci.electronics.repair/t/7ea92a246fb6ba99?hl=en
==============================================================================

== 1 of 1 ==
Date: Sat, Jan 29 2011 5:48 am
From: success all

http://USAforextradingonline.blogspot.com

==============================================================================
TOPIC: possibly OT: players reject region 0 DVD
http://groups.google.com/group/sci.electronics.repair/t/b38242427b60f545?hl=en
==============================================================================

== 1 of 3 ==
Date: Sat, Jan 29 2011 6:00 am
From: "William Sommerwerck"

One of my recent SACD purchases included a bonus region 0 "making of" DVD. A
Sony BD player and DVD player both rejected the disk, on the basis of region
incompatibility.

This is decidedly odd, as region 0 disks are supposed to play on any player.
(Right?)

What am I missing?

Please don't turn this simple question into a tsimmes or megillah. Thanks.

--
"We already know the answers -- we just haven't asked the right
questions." -- Edwin Land

== 2 of 3 ==
Date: Sat, Jan 29 2011 8:16 am
From: "Arfa Daily"

"William Sommerwerck" <grizzledgeezer@comcast.net> wrote in message
news:ii16ip$qcb$2@news.eternal-september.org...
> One of my recent SACD purchases included a bonus region 0 "making of" DVD.
> A
> Sony BD player and DVD player both rejected the disk, on the basis of
> region
> incompatibility.
>
> This is decidedly odd, as region 0 disks are supposed to play on any
> player.
> (Right?)
>
> What am I missing?
>
> Please don't turn this simple question into a tsimmes or megillah. Thanks.
>
> --
> "We already know the answers -- we just haven't asked the right
> questions." -- Edwin Land
>
>

"Region 0", if truly so, should be region - *less*, and as you say, any
player should handle them without issue. I have several demo and test discs
which are region 0 designated, and I have never found a player that refused
them in the course of my daily repair activities. Why yours should reject
them, is a mystery ...

Arfa

== 3 of 3 ==
Date: Sat, Jan 29 2011 9:26 am
From: "William Sommerwerck"

> "Region 0", if truly so, should be region -- *less*, and as
> you say, any player should handle them without issue.
> I have several demo and test discs which are region 0
> designated, and I have never found a player that refused
> them in the course of my daily repair activities. Why
> yours should reject them, is a mystery ...

I'll contact Sony and Alia Vox. Maybe Jordi Savall will drop by to check.
(heh, heh, heh...)

==============================================================================
TOPIC: CRT Monitor Philips black screen when cold
http://groups.google.com/group/sci.electronics.repair/t/5e3cab73ac7d259c?hl=en
==============================================================================

== 1 of 2 ==
Date: Sat, Jan 29 2011 8:01 am
From: "Steinway"

Hallo!
My CRT monitor, Philips 109B, has black screen after 2 seconds when it is
cold: the picture becomes bigger and fades away.
If I turn it off and turn on, the picture again becomes bigger and fades
out.
When it is warm, after 20-30 minutes, if I turn it off and turn on, the
screen appears and works very good.
Could it be a cap?
Thank you!
S.

== 2 of 2 ==
Date: Sat, Jan 29 2011 10:17 am
From: Jamie

Steinway wrote:

> Hallo!
> My CRT monitor, Philips 109B, has black screen after 2 seconds when it is
> cold: the picture becomes bigger and fades away.
> If I turn it off and turn on, the picture again becomes bigger and fades
> out.
> When it is warm, after 20-30 minutes, if I turn it off and turn on, the
> screen appears and works very good.
> Could it be a cap?
> Thank you!
> S.
>
>
Get your solder iron out and start cleaning up those joints..

Jamie

==============================================================================
TOPIC: Two phases or not?
http://groups.google.com/group/sci.electronics.repair/t/0a29a801d6e01e9e?hl=en
==============================================================================

== 1 of 1 ==
Date: Sat, Jan 29 2011 8:44 am
From: bud--

David Nebenzahl wrote:
> On 1/28/2011 11:28 AM Mark Cross spake thus:
>
>> David Nebenzahl wrote:
>>
>>> So what's "special" or magic about 180° that it wouldn't be considered a
>>> completely separate and distinct phase? Why would phase have a "hole" at
>>> 180°? (And for any wisenheimers who will say "well, you must consider 0°
>>> to be a separate phase too!" I say nonsense: that's just a phase
>>> "identity" which we can ignore as being identical to the original
>>> phase.)

So you get 2 phases out of a single phase power transformer?
With 2 separate secondary windings there are 2 phases. Winding A is not
the same as winding B.

With 3 separate secondary windings there are 3 separate phases. Winding
A is not the same as winding B. And winding C is not the same as A. And
C is not the same as B.

With 4 separate secondary windings there are 4 phases. ....

Your transformer supplier can furnish a single core transformer with 4
secondary phases?
Your transformer supplier can furnish a single-core transformer with 2
secondary phases?

>
>> To understand what is "magical" about that you will need to know
>> phasors and the math related to that. Once you understand the math
>> that support phasors, you clearly see why 0º and 180º are the same
>> phasor.
>>
>> http://en.wikipedia.org/wiki/Phasor
>
> Sorry, I don't use Wikipedia as a source of credible information.

Then use your own knowledge of phasors. The representation of a 120/240V
service (relative to N) is +120 and -120, both real. There are no
imaginary components. Plus and minus relationships.

>
> But even if 0º and 180º are the same phasor, they're still completely
> different waveforms, which is the important thing here, isn't it?
>

Completely different waveforms? Plus sine is a completely different
waveform from minus sine. Have you taken trigonometry? On a transformer
secondary the relative relationships are locked at plus or minus. 180
degrees is trivial.

When you are doing calculations on a simple single-phase resistive
system you use phase angles? Most of us use plus and minus signs. With
non-resistive elements phasors are used - see above.

You can, of course, call it whatever you want to. Just expect
communication problems. I remember 2 people here who agree with you. It
is not the only 2 people I would want agreeing with me. Maybe you could
shop around to a different newsgroup - maybe alt.engineering.electrical?

And two-phase does still exist. Some relatively small 3-phase to 3-phase
transformers (like 480/277 to 208/120) connect 2 transformers in a Scott
(T) connection. The transformers are an intermediate 2-phase. That is,
real 2-phase - 90 degrees between the voltages

--
bud--

==============================================================================
TOPIC: ♀♂Here ! wholesale and retail shoes,sunglasses,t-shirts,clothes¡¬
http://groups.google.com/group/sci.electronics.repair/t/c67416da3e27d9c8?hl=en
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== 1 of 1 ==
Date: Sat, Jan 29 2011 9:27 am
From: gc hu

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