sci.electronics.repair@googlegroups.com

Today's topics:

* CRT Monitor Philips black screen when cold - 3 messages, 3 authors
http://groups.google.com/group/sci.electronics.repair/t/5e3cab73ac7d259c?hl=en
* Two phases or not? - 9 messages, 5 authors
http://groups.google.com/group/sci.electronics.repair/t/0a29a801d6e01e9e?hl=en
* Yamaha EMX5016 mixer amp from 2006 - 1 messages, 1 author
http://groups.google.com/group/sci.electronics.repair/t/bc288deddd9278ea?hl=en
* Datasheet required STK795-820 or 821 - 1 messages, 1 author
http://groups.google.com/group/sci.electronics.repair/t/632acd16eeba7502?hl=en
* DTV sound synch - 7 messages, 6 authors
http://groups.google.com/group/sci.electronics.repair/t/2896d12048fef530?hl=en
* Laptop not charging. - 2 messages, 2 authors
http://groups.google.com/group/sci.electronics.repair/t/3f52116e8141f1a4?hl=en
* possibly OT: players reject region 0 DVD - 2 messages, 2 authors
http://groups.google.com/group/sci.electronics.repair/t/b38242427b60f545?hl=en

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

== 1 of 3 ==
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

== 2 of 3 ==
Date: Sat, Jan 29 2011 10:51 am
From: "N_Cook"

Jamie <jamie_ka1lpa_not_valid_after_ka1lpa_@charter.net> wrote in message
news:kCY0p.26450$Tg1.14228@newsfe13.iad...
> 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
>
>
>

If the picture is changing X and Y dimensions then an acceleration voltage
is playing up, reducing magnitude leading to increasing dimensions but
fading image

== 3 of 3 ==
Date: Sat, Jan 29 2011 4:46 pm
From: "circuit"

bad cap in the flyback xfmr

"Steinway" <slkjdskd> wrote in message
news:4d4439d7$0$2045$4fafbaef@reader1.news.tin.it...
> 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.
>
>

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

== 1 of 9 ==
Date: Sat, Jan 29 2011 10:37 am
From: Jamie

bud-- wrote:

> 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
>
Yes, 2 phase of 90 degree's still exist, so why is that ok but 180
degree's isn't?

Look at power generators (portables), most of them have 2 circuits
from the generator 180 out from each other.. Why is this any different
from a
generator of 90 degrees out ? You can combine a leg of each output from
a those generators also..

It's argument that you won't win from those that truly understand the
meaning of phase angle supplies and the number of supply legs.

Its clear that the maximum you can obtain is only 2 phase angles from
any combination of CT's on a transformer supplied from a single phase
leg how ever, the number of circuits from a transformer can be endless
but not practical, of course.

== 2 of 9 ==
Date: Sat, Jan 29 2011 10:38 am
From: "Michael A. Terrell"

Jamie wrote:
>
> bud-- wrote:
>
> > 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
> >
> Yes, 2 phase of 90 degree's still exist, so why is that ok but 180
> degree's isn't?
>
> Look at power generators (portables), most of them have 2 circuits
> from the generator 180 out from each other.. Why is this any different
> from a
> generator of 90 degrees out ? You can combine a leg of each output from
> a those generators also..
>
> It's argument that you won't win from those that truly understand the
> meaning of phase angle supplies and the number of supply legs.
>
> Its clear that the maximum you can obtain is only 2 phase angles from
> any combination of CT's on a transformer supplied from a single phase
> leg how ever, the number of circuits from a transformer can be endless
> but not practical, of course.

This, from an illiterate ham radio junkie?

--
You can't fix stupid. You can't even put a band-aid on it, because it's
Teflon coated.

== 3 of 9 ==
Date: Sat, Jan 29 2011 11:20 am
From: Mark Cross

Jamie wrote:

> Yes, 2 phase of 90 degree's still exist, so why is that ok but 180
> degree's isn't?

Because the decomposition of two 90º phasor contains an imaginary part.
Without a real part AND an imaginary part, no distinct phases could be
constructed or generated.

There is no imaginary part in the decomposition of two 180º apart vectors,
and, therefore there is no way to construct other phases (phasors).

Sorry, you need to know phasors to understand this principle.

--
Mark Cross
If Linux doesn't have the solution, you have the wrong problem.

== 4 of 9 ==
Date: Sat, Jan 29 2011 12:19 pm
From: Jamie

Mark Cross wrote:

> Jamie wrote:
>
>
>>Yes, 2 phase of 90 degree's still exist, so why is that ok but 180
>>degree's isn't?
>
>
> Because the decomposition of two 90º phasor contains an imaginary part.
> Without a real part AND an imaginary part, no distinct phases could be
> constructed or generated.
>
> There is no imaginary part in the decomposition of two 180º apart vectors,
> and, therefore there is no way to construct other phases (phasors).
>
> Sorry, you need to know phasors to understand this principle.
>

This must be what separates the Electronic and the Fuse puller EE.

I once thought to be an Electrical Engineer or hold an E1 meant, that
you had to know a lot about electricity, evidently you don't. Might be a
good reason why we find it hard to hire some one for a basic electrical
maintenance job that actual understands electrical theory, not many here.

Jamie

== 5 of 9 ==
Date: Sat, Jan 29 2011 12:07 pm
From: "Michael A. Terrell"

Jamie wrote:
>
> Mark Cross wrote:
>
> > Jamie wrote:
> >
> >
> >>Yes, 2 phase of 90 degree's still exist, so why is that ok but 180
> >>degree's isn't?
> >
> >
> > Because the decomposition of two 90º phasor contains an imaginary part.
> > Without a real part AND an imaginary part, no distinct phases could be
> > constructed or generated.
> >
> > There is no imaginary part in the decomposition of two 180º apart vectors,
> > and, therefore there is no way to construct other phases (phasors).
> >
> > Sorry, you need to know phasors to understand this principle.
> >
>
> This must be what separates the Electronic and the Fuse puller EE.
>
> I once thought to be an Electrical Engineer or hold an E1 meant, that
> you had to know a lot about electricity, evidently you don't. Might be a
> good reason why we find it hard to hire some one for a basic electrical
> maintenance job that actual understands electrical theory, not many here.

Actually, you can't find enough idiots willing to kiss your stupid
ass.

--
You can't fix stupid. You can't even put a band-aid on it, because it's
Teflon coated.

== 6 of 9 ==
Date: Sat, Jan 29 2011 12:30 pm
From: Mark Cross

Jamie wrote:

> that
> you had to know a lot about electricity, evidently you don't.

I am not looking for a job, much less in basic electrical maintenace. You
may apply if you feel competent for such simple jobs.

--
Mark Cross
If Linux doesn't have the solution, you have the wrong problem.

== 7 of 9 ==
Date: Sat, Jan 29 2011 1:34 pm
From: Jeffrey Angus

On 1/29/2011 12:37 PM, Jamie wrote:

> Yes, 2 phase of 90 degree's still exist, so why is that ok but 180
> degree's isn't?

Because it's STILL a SINGLE phase across the transformer.

> Look at power generators (portables), most of them have 2 circuits from
> the generator 180 out from each other.. Why is this any different from a
> generator of 90 degrees out ? You can combine a leg of each output from
> a those generators also..

I serious doubt they make 90 Degree 2-phase generators.

As to combining multiple output windings from a SINGLE phase
generator, the output is STILL single phase.

> It's argument that you won't win from those that truly understand the
> meaning of phase angle supplies and the number of supply legs.

You're right, _YOU_ won't win that argument.

On combining multiple phases...

On more occasions than I care to recall, I've seen some poor
schmuck buy a 3-5 HP 240 VAC single phase motor, either on a
table saw or an air compressor, and have his "electrician
buddy" give him two of the 120 volt phases of the 3-phase
power in the shop to run his new equipment with.

Aside from the obvious, the voltage is 208 (Not 240), there's
a 120 phase difference between the two leads feeding the motor.
I usually get called in about 2-3 weeks on a "warranty request"
for said motor that just went up in flames.

Jeff

== 8 of 9 ==
Date: Sat, Jan 29 2011 4:24 pm
From: "Michael A. Terrell"

Jeffrey Angus wrote:
>
> On 1/29/2011 12:37 PM, Jamie wrote:
>
> > Yes, 2 phase of 90 degree's still exist, so why is that ok but 180
> > degree's isn't?
>
> Because it's STILL a SINGLE phase across the transformer.
>
> > Look at power generators (portables), most of them have 2 circuits from
> > the generator 180 out from each other.. Why is this any different from a
> > generator of 90 degrees out ? You can combine a leg of each output from
> > a those generators also..
>
> I serious doubt they make 90 Degree 2-phase generators.
>
> As to combining multiple output windings from a SINGLE phase
> generator, the output is STILL single phase.
>
> > It's argument that you won't win from those that truly understand the
> > meaning of phase angle supplies and the number of supply legs.
>
> You're right, _YOU_ won't win that argument.
>
> On combining multiple phases...
>
> On more occasions than I care to recall, I've seen some poor
> schmuck buy a 3-5 HP 240 VAC single phase motor, either on a
> table saw or an air compressor, and have his "electrician
> buddy" give him two of the 120 volt phases of the 3-phase
> power in the shop to run his new equipment with.
>
> Aside from the obvious, the voltage is 208 (Not 240), there's
> a 120 phase difference between the two leads feeding the motor.
> I usually get called in about 2-3 weeks on a "warranty request"
> for said motor that just went up in flames.

I recently got a call about a pipe bending machine reporting low
voltage. Rated for 208 to 240 volts and was working fine a couple days
earlier, before it was moved to a new building. They insisted the
wiring was fine, and asked me to add a boost transformer. I did, and it
still didn't work. I finally convinced them to let me check the
voltage. I had 154 volts after the boost transformer, so i went to the
new three phase breaker box and found that someone like Jamie had wired
it. The black wire went to a single pole breaker, and the red went to
neutral. The business owner finally got hold of the company that did
the wiring, who insisted they did the job the right way. When they were
informed that they had used a single pole breaker, they called him a
liar but reluctantly agreed to send out a worker. Three hours later, he
shows up, admits they used the wrong breaker and promised to be back
'sometime next week'. After another couple calls, the owner of the
electrical business delivers the proper breaker. Guess who will ever be
called for any more work?

With 208 going to the boost transformer, I had 244 volts to the
machine. The operator's eyes went wide when he used it. He said it was
working about 50% faster, and bending at the speed it was supposed to.
It had never worked at full speed in the 10+ years they had owned it.

As far as the knuckle draggers:

You can buy single pole breakers.
You can buy double pole breakers.
You can buy three phase breakers.
--- BUT ---
You can't buy two phase breakers.

--
You can't fix stupid. You can't even put a band-aid on it, because it's
Teflon coated.

== 9 of 9 ==
Date: Sat, Jan 29 2011 5:35 pm
From: "Phil Allison"

"Mark Cross"
>
> 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.

** ABSOLUTE Bollocks.

> http://en.wikipedia.org/wiki/Phasor

** Says nothing of the kind whatever.

( Bet the only "phasors" this jerk knows about are the ones used on "Star
Trek")

Fuck of you pathetic, bloody TROLL 1!

..... Phil

==============================================================================
TOPIC: Yamaha EMX5016 mixer amp from 2006
http://groups.google.com/group/sci.electronics.repair/t/bc288deddd9278ea?hl=en
==============================================================================

== 1 of 1 ==
Date: Sat, Jan 29 2011 10:46 am
From: "N_Cook"

repair m on e-S and there is an inverter stuck in before the R ch o/p, not
for the L

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

== 1 of 1 ==
Date: Sat, Jan 29 2011 10:56 am
From: Stroonz

On Jan 29, 11:29 am, "Arfa Daily" <arfa.da...@ntlworld.com> wrote:
>
>
> >> 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

Thanks sir. I appreciate the effort. I was hoping I was either
missing something, or that someone would have a sheet stored
somewhere.

Edwin

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

== 1 of 7 ==
Date: Sat, Jan 29 2011 11:03 am
From: Fred McKenzie

In article <4d439097$0$23162$822641b3@news.adtechcomputers.com>,
David Nebenzahl <nobody@but.us.chickens> 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.

I'm surprised there aren't more complaints about this. Two HD
television sets connected to the same antenna system can have an audio
difference between the two. Weak signal conditions seem to be the
worst, with very obvious delay just before the picture breaks up.

There are probably several reasons for the discrepancy, but there is no
excuse. Audio-video sync shouldn't be a problem with a digital system,
but the current HD system is obviously weak in this area. Perhaps there
is a delay due to the need for error correction when signals are poor.
If so, why isn't one delayed so both audio and video are presented at
the same time? It might take some extra memory to hold delayed data,
and maybe an algorithm to shed an occasional video frame. Or is it the
other way around, with audio leading the video?

I haven't seen this mentioned in Consumer Reports television reviews, so
few of us are complaining about it!

Fred

== 2 of 7 ==
Date: Sat, Jan 29 2011 11:22 am
From: David Nebenzahl

On 1/29/2011 11:03 AM Fred McKenzie spake thus:

> In article <4d439097$0$23162$822641b3@news.adtechcomputers.com>,
> David Nebenzahl <nobody@but.us.chickens> 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.
>
> I'm surprised there aren't more complaints about this. Two HD
> television sets connected to the same antenna system can have an audio
> difference between the two. Weak signal conditions seem to be the
> worst, with very obvious delay just before the picture breaks up.
>
> There are probably several reasons for the discrepancy, but there is no
> excuse. Audio-video sync shouldn't be a problem with a digital system,
> but the current HD system is obviously weak in this area. Perhaps there
> is a delay due to the need for error correction when signals are poor.
> If so, why isn't one delayed so both audio and video are presented at
> the same time? It might take some extra memory to hold delayed data,
> and maybe an algorithm to shed an occasional video frame. Or is it the
> other way around, with audio leading the video?

Judging by the behavior of my system (set-top DTV box, Zenith DTT901),
I'd say that the audio is simply sacrificed for the sake of displaying
video. When there's a marginal signal coming in, the video will continue
to be displayed, albeit with some break-up and possible freezing, while
the audio simply drops out.

--
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.

== 3 of 7 ==
Date: Sat, Jan 29 2011 11:48 am
From: stratus46@yahoo.com

On Jan 29, 3:36 am, Jeffrey Angus <jan...@suddenlink.net> wrote:
<snip>
> 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

It still does mean something and if you ever thought revenue WASN'T a
part of it, you're just wrong. I get to see 'broadcast quality' video
from the 60's and 70's at work and while it was good in its day, it
doesn't hold a candle to what you have now. I'm one of those 'techs'
and I can tell you we DO give a hoot about how it looks and sounds.

G²

== 4 of 7 ==
Date: Sat, Jan 29 2011 11:54 am
From: "N_Cook"

David Nebenzahl <nobody@but.us.chickens> wrote in message
news:4d44689c$0$2178$822641b3@news.adtechcomputers.com...
> On 1/29/2011 11:03 AM Fred McKenzie spake thus:
>
> > In article <4d439097$0$23162$822641b3@news.adtechcomputers.com>,
> > David Nebenzahl <nobody@but.us.chickens> 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.
> >
> > I'm surprised there aren't more complaints about this. Two HD
> > television sets connected to the same antenna system can have an audio
> > difference between the two. Weak signal conditions seem to be the
> > worst, with very obvious delay just before the picture breaks up.
> >
> > There are probably several reasons for the discrepancy, but there is no
> > excuse. Audio-video sync shouldn't be a problem with a digital system,
> > but the current HD system is obviously weak in this area. Perhaps there
> > is a delay due to the need for error correction when signals are poor.
> > If so, why isn't one delayed so both audio and video are presented at
> > the same time? It might take some extra memory to hold delayed data,
> > and maybe an algorithm to shed an occasional video frame. Or is it the
> > other way around, with audio leading the video?
>
> Judging by the behavior of my system (set-top DTV box, Zenith DTT901),
> I'd say that the audio is simply sacrificed for the sake of displaying
> video. When there's a marginal signal coming in, the video will continue
> to be displayed, albeit with some break-up and possible freezing, while
> the audio simply drops out.
>
>
> --
> 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.

Back in the days when there were engineers , they designed a colour TV
system
In slightly degraded signal conditions you lost colour - could still follow
a film say
Worse propogation and picture became snowy - still followable
Worse and sound became noisey and syncs being lost - just about followable
Finally the sound would go

These days its all arse about face, sound is the first to go and colour is
the last to go

== 5 of 7 ==
Date: Sat, Jan 29 2011 12:51 pm
From: Meat Plow

On Sat, 29 Jan 2011 11:22:19 -0800, David Nebenzahl wrote:

> On 1/29/2011 11:03 AM Fred McKenzie spake thus:
>
>> In article <4d439097$0$23162$822641b3@news.adtechcomputers.com>,
>> David Nebenzahl <nobody@but.us.chickens> 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.
>>
>> I'm surprised there aren't more complaints about this. Two HD
>> television sets connected to the same antenna system can have an audio
>> difference between the two. Weak signal conditions seem to be the
>> worst, with very obvious delay just before the picture breaks up.
>>
>> There are probably several reasons for the discrepancy, but there is no
>> excuse. Audio-video sync shouldn't be a problem with a digital system,
>> but the current HD system is obviously weak in this area. Perhaps
>> there is a delay due to the need for error correction when signals are
>> poor. If so, why isn't one delayed so both audio and video are
>> presented at the same time? It might take some extra memory to hold
>> delayed data, and maybe an algorithm to shed an occasional video frame.
>> Or is it the other way around, with audio leading the video?
>
> Judging by the behavior of my system (set-top DTV box, Zenith DTT901),
> I'd say that the audio is simply sacrificed for the sake of displaying
> video. When there's a marginal signal coming in, the video will continue
> to be displayed, albeit with some break-up and possible freezing, while
> the audio simply drops out.

Newest Sci-Atlanta DTVHD-DVR, TWC here. Don't notice a lot of sync
problems. Being a musician I would notice even a few milliseconds.

More problems with picture fizzle-out accompanied by audio drops and buzz
on HD channels. Signal tested recently. Found to be high-normal in the HD
range. Nothing to bitch about except when Discovery-HD fizzed and buzzed
every 10 seconds. A new DVR fixed that.

--
Live Fast, Die Young and Leave a Pretty Corpse

== 6 of 7 ==
Date: Sat, Jan 29 2011 4:29 pm
From: "Dave Plowman (News)"

In article
<d7b4be9b-6843-425c-92c4-62788a3276e3@f30g2000yqa.googlegroups.com>,
<stratus46@yahoo.com> wrote:
> It still does mean something and if you ever thought revenue WASN'T a
> part of it, you're just wrong. I get to see 'broadcast quality' video
> from the 60's and 70's at work and while it was good in its day, it
> doesn't hold a candle to what you have now. I'm one of those 'techs'
> and I can tell you we DO give a hoot about how it looks and sounds.

It's very unlikely you are seeing broadcast electronic video from the 60s
and 70s as good as it was then. It'll have been transferred a few times as
tape formats go out of use - and the transfer equipment likely towards the
end of its life. Plus the fact that even a single generation of quad VTR
caused noticeable degradation, and most of the stuff which has been kept
will be two or more generations.

--
*If you try to fail and succeed, which have you done? *

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

== 7 of 7 ==
Date: Sat, Jan 29 2011 5:13 pm
From: David Nebenzahl

On 1/29/2011 12:51 PM Meat Plow spake thus:

> On Sat, 29 Jan 2011 11:22:19 -0800, David Nebenzahl wrote:
>
>> Judging by the behavior of my system (set-top DTV box, Zenith DTT901),
>> I'd say that the audio is simply sacrificed for the sake of displaying
>> video. When there's a marginal signal coming in, the video will continue
>> to be displayed, albeit with some break-up and possible freezing, while
>> the audio simply drops out.
>
> Newest Sci-Atlanta DTVHD-DVR, TWC here. Don't notice a lot of sync
> problems. Being a musician I would notice even a few milliseconds.

OK, but how about other channels? The out-of-synch problem seems to be
the worst on a local public station that runs a mish-mosh of programming
with *extremely* low standards for any kind of production values, but
I've noticed it even on network stations (NBC, ABC, etc.) where even
speech doesn't match the speaker's lips.

> More problems with picture fizzle-out accompanied by audio drops and buzz
> on HD channels. Signal tested recently. Found to be high-normal in the HD
> range. Nothing to bitch about except when Discovery-HD fizzed and buzzed
> every 10 seconds. A new DVR fixed that.

Oddly enough, I've never experienced *any* of those problems with DTV.
Just audio drop-out, but no buzz, hum, distortion, etc.

--
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.

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

== 1 of 2 ==
Date: Sat, Jan 29 2011 1:02 pm
From: Meat Plow

On Sat, 29 Jan 2011 12:24:18 +0000, 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

Something broke inside around the power socket. Some strong light an a
20x magnifying visor might help you find the break.

--
Live Fast, Die Young and Leave a Pretty Corpse

== 2 of 2 ==
Date: Sat, Jan 29 2011 4:59 pm
From: T i m

On Sat, 29 Jan 2011 13:50:38 +0000, Adrian C <email@here.invalid>
wrote:

>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

Thanks for that. ;-)
>
>You'll have to join the forum to download taking care to practice 'safe
>hex' with documents you may get.

"Sorry, You should have 10 Points to download: ..."?

I'm not sure how I glean points there and whatever it is I'm not sure
I could do so in Vietnamese (even with Google translate).

Frustratingly close though ...

Cheers, T i m

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

== 1 of 2 ==
Date: Sat, Jan 29 2011 1:08 pm
From: Meat Plow

On Sat, 29 Jan 2011 09:26:34 -0800, William Sommerwerck wrote:

>> "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...)

Maybe the disc isn't detected as 0. Stick it in a PC dvd player and use
DVD Identifier to see what region info the disc actually gives.

Did the BD of DVD player give you a more specific error? Most allow a
change of region up to 4 times. Well I know a PC DVD drives allows this.

--
Live Fast, Die Young and Leave a Pretty Corpse

== 2 of 2 ==
Date: Sat, Jan 29 2011 2:03 pm
From: "William Sommerwerck"

> Maybe the disc isn't detected as 0. Stick it in a PC DVD
> player and use DVD Identifier to see what region info the
> disc actually gives.

Thank you! I didn't know how to do that.

---------------

I still don't.

I inserted the disk, and it auto-ran without prompting for a region,
suggesting that the region was zero (that is, no specified region). I
couldn't find anything in the Roxio applet to identify the region.

Runs fine on a 10-year-old computer, by the way.

> Did the BD or DVD player give you a more-specific error?

The standalone DVD player which said specifically that the region was
unacceptable.

> Most allow a change of region up to 4 times.

My Plextor PX-708A was bought primarily to burn CDs. I've never played a DVD
in it, so I've never had to select a region. (I think it allows three
changes.)

By the way, Sony has already responded, and as you might guess, the answer
had nothing whatever to do with the question.

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