Toshiba TV29C90 problem; Image fades to black...

[Engineer]

"ed" <endeitz@gmail.com> wrote in message
news:1118531526.863099.322750@g47g2000cwa.googlegroups.com...

Hello,

I know little about electrical issues, so I am looking for some help
answering two questions:

1. I have a cordless drill with an 18V nicad pack. At some point,
the
charger failed (no voltage measured off the leads).

I read the thread to date - agree with all points made.

BTW, not totally O/T but I have given up on Nicad powerd screwdrivers.
In the three I have had, all of them had failed sub-C size NiCads
would have cost more to replace than the whole unit cost in the first
place! I had modest success in the beginning by canibalizing good
sub-C cells from dead drills to keep the other running. I right PITA,
they are welded together. Eventually, I gave up and now I just power
them from a junked PC power supply (the 5 VDC high current output.)
Don't worry obout the higher voltage; the nominally 3.6 volt motor
thrives on 5 volts - lots of torque and still going strong! You do
have to live with a 16 gauge wire lead, though, and plugging in the
P/S at the worksite.

I also have a small B&D drill (6 VDC.) While it's still going
"strognishly", it now seems to need charging more often - I suspect
its going the way of the screwdrivers. I'll have to find a wired P/S
solution again!

Cheers,
Roger

 

[Helen]

"Katt" <seruhshjaudn@dfhu.net> wrote in message
news:dmYqe.7425$q46.942@newsfe1-win.ntli.net...

"Helen" <@abuse.roman.gov> wrote in message
news:kVWqe.686$zm.363@bignews4.bellsouth.net...

The pathetic ego of this Troll suffices as evidence
that this is atheistic behavior
designed to elicit the exact response you gave.

Curious comment. Ego = atheist?

Katt.


It was his(?) benefit and he'll know exactly what it means.

"Beware a little leaven in the bread...."
And....
"They willl say, 'didn't I do thus and such for you?" And
didn't I, and didn't I, and didn't I....I I I I-I- I....
And HE will say, 'get away from me, I never knew you!"

By their fruits shall ye know them.

 

[John Fields]

On 10 Jun 2005 23:42:58 -0700, jackbruce9999@yahoo.com wrote:

Go back to the original few posts to see how it got started....despite
being explicit about the specs of the wave, someone childishly objected
to my casual usage of "DC sine wave".....would it have been
objectionable had I used "a fully DC-offset sine wave"?......again,
I've never claimed that I was using "official" or
conventionally-correct teminology or nomenclature....I just really
object that anyone would object to what I was saying, when its meaning
was explicitly stated (using actual numbers) and the phrase "fully DC
sine wave", although conventionly queer, is not at all cryptic or hard
to figure out......if I were a chemist and someone said "200 degrees
above the freezing point of water", I wouldn't mock them, just
respectfully point out that it's more common to say "20 degrees above
the boiling point of water".....I would consider the person ignorant of
the conventional terminology, but I would consider the person dead-on
if he were talking about 232 degrees F.

---
The reason you're being mocked is because you're grasping at straws
trying to defend the position that it's all right to use incorrect
terminology. It isn't, and the sooner you stop whining about how
you'd do it if you were in someone else's shoes, the better.

--
John Fields
Professional Circuit Designer

 

[Floyd L. Davidson]

"operator jay" <none@none.none> wrote:

"Floyd L. Davidson" <floyd@barrow.com> wrote in message
news:87y89fzqcu.fld@barrow.com...

The problem is that "direction" only has meaning when measured
in comparison some specific point of reference. If you have
three different reference points, one at the DC level, one at
the peak positive swing and one at the peak negative swing, you
have three very different views of "direction" for current flow:

Reference Direction
Point of flow
========= =====================================

Peak Pos All Negative

DC level Equal cycles of Positive and Negative

Peak Neg All Positive



I think "zero" is a good reference for current flow, and that the actual

Sure... now, can you define "zero"?

(absolute) direction can be measured. Voltages have the reference issues.

E =IR

Since our resistance is fixed, it's the exact same issue, though
perhaps easier to understand, with voltage. (I gave some
consideration as to whether to post that with voltage or current
references, and since "AC" and "DC" use the term "current",
decided to go with current to avoid the easier path to the same
statement you are making.)

--
Floyd L. Davidson <http://web.newsguy.com/floyd_davidson>
Ukpeagvik (Barrow, Alaska) floyd@barrow.com

 

[Dave Plowman (News)]

In article <1118531526.863099.322750@g47g2000cwa.googlegroups.com>,
ed <endeitz@gmail.com> wrote:

So here's the question: what about this battery pack makes the
transformer heat up to the point it burns out? There doesn't seem to
be a short in the battery pack, just a few bad cells. . .I don't
understand why this gives the transformer such grief.

Ni-Cads should really be charged constant current with a 'simple' charger.
Now if the charger itself was designed as a constant current device, then
increasing the load (with say a short cell) shouldn't worry it too much.

But I've seen so called rapid chargers on cheap power tools (4 hr charge)
where the charger is simply unregulated DC with a series resistor to give
something *vaguely* near constant current.

And of course few carry a stopwatch around to make sure they don't cook
them - as you will, if the four hour limit is exceeded by much.

So I'd have a look inside the charger base to see what it's actually got
in the way of electronics.

--
*A nest isn't empty until all their stuff is out of the attic

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

 

[Dave Plowman (News)]

In article <MrGdnViz5dNxyDHfRVn-gw@rogers.com>,
Engineer <fakeaddress@nowhere.net> wrote:

BTW, not totally O/T but I have given up on Nicad powerd screwdrivers.
In the three I have had, all of them had failed sub-C size NiCads
would have cost more to replace than the whole unit cost in the first
place! I had modest success in the beginning by canibalizing good
sub-C cells from dead drills to keep the other running. I right PITA,
they are welded together.

Cheap cordless tools use cheap cells and even cheaper chargers.

Replacing those cheap cells with decent ones - and modifying the charger
to an intelligent type, or even just the old 14 hour type, can transform
that tool. Doing this to my cheap 18 volt drill driver made the starting
torque much higher - and easier to control.

Some of the reasons why an Hitachi costs perhaps 10 times more than a shed
special. ;-)

--
*Don't sweat the petty things and don't pet the sweaty things.

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

 

[operator jay]

"Floyd L. Davidson" <floyd@barrow.com> wrote in message
news:87mzpvzftb.fld@barrow.com...

"operator jay" <none@none.none> wrote:
"Floyd L. Davidson" <floyd@barrow.com> wrote in message
news:87y89fzqcu.fld@barrow.com...

The problem is that "direction" only has meaning when measured
in comparison some specific point of reference. If you have
three different reference points, one at the DC level, one at
the peak positive swing and one at the peak negative swing, you
have three very different views of "direction" for current flow:

Reference Direction
Point of flow
========= =====================================

Peak Pos All Negative

DC level Equal cycles of Positive and Negative

Peak Neg All Positive



I think "zero" is a good reference for current flow, and that the actual

Sure... now, can you define "zero"?

Put an ammeter there and it says zero. That's zero. Electrons bouncing
around in the conductor have an average net displacement, over time, of 0.

(absolute) direction can be measured. Voltages have the reference
issues.

E =IR

Since our resistance is fixed, it's the exact same issue, though
perhaps easier to understand, with voltage. (I gave some
consideration as to whether to post that with voltage or current
references, and since "AC" and "DC" use the term "current",
decided to go with current to avoid the easier path to the same
statement you are making.)

Current is a different issue from voltage because voltage is a relative
quantity. It is a type of measurement of a change in field between two
locations. Current is a rate of flow of charge at a single location (well,
typically, through a single Gaussian surface), and is measurable at that
location, and does not have the ambiguity that voltage has. It does not
need a reference. If I say that my toaster is running at 120V and 8A, you
may ask "120V relative to what" and I'll answer "neutral". You would not
ask "8A relative to what".

j

 

[Bob Parker]

It's because of this kind of irrelevant garbage that I've haven't
taken newsgroups seriously for a long time and barely glance at them
now. It's true: "On the internet, things which usually live under
rocks are suddenly in your face".
I'm sure there's a newsgroup for "born-again loony Christians".
Please go there and stop wasting our time and bandwidth.



"Helen" <@abuse.roman.gov> wrote:

"Katt" <seruhshjaudn@dfhu.net> wrote in message
news:dmYqe.7425$q46.942@newsfe1-win.ntli.net...
"Helen" <@abuse.roman.gov> wrote in message
news:kVWqe.686$zm.363@bignews4.bellsouth.net...

The pathetic ego of this Troll suffices as evidence
that this is atheistic behavior
designed to elicit the exact response you gave.

Curious comment. Ego = atheist?

Katt.


It was his(?) benefit and he'll know exactly what it means.
"Beware a little leaven in the bread...."
And....
"They willl say, 'didn't I do thus and such for you?" And
didn't I, and didn't I, and didn't I....I I I I-I- I....
And HE will say, 'get away from me, I never knew you!"

By their fruits shall ye know them.

 

[Kitchen Man]

On Sun, 12 Jun 2005 14:33:39 -0500, John Fields
<jfields@austininstruments.com> wrote:

On 12 Jun 2005 09:01:11 -0700, mabelmapleleaf@yahoo.com wrote:

It's a shame you have to weed thru all the crap from some
of the posters here who have a lot of time on their hands and
have no tolerance for those who are just learning their craft....

---
It's a shame that those of us who give of our time in an effort to
edify the ignorant are often abused by imbeciles who can't take
correction gracefully.

It is equally a shame that there are those that are sometimes
incapable of offering correction gracefully, eh, John? If it pains
you so much to engage in your ungracious edifying, perhaps you would
do well to bugger off, and leave the stress of educating imbeciles to
those with more patience.

--
Al Brennan

"If you only knew the magnificence of the 3, 6 and 9,
then you would have a key to the universe." Nicola Tesla

 

[Kitchen Man]

On 10 Jun 2005 23:06:10 -0700, jackbruce9999@yahoo.com wrote:

Again, is the term "DC Sine Wave" problematic because it is
fundametnally wrong

Yes. DC by definition is zero frequency

Nice parse-job.....here's my original entire comment in context:

Again, is the term "DC Sine Wave" problematic because it is
fundametnally wrong OR is it problematic because it is at odds with
conventional terminology and nomenclature

You conveinently left out the "OR...." part.

If we may plunge for a moment into basic boolean logic, the "OR" part
is no longer necessary once one part of the proposition is shown to be
true. Thus, not only was his omission convenient, it was proper.

You actually proved my
point that DC is DEFINED (i.e. by convention) as "zero frequency".
Is it that weird to posit that the superior concept with respect to
considering any signal as AC or DC, be the actual NET current flow? I
could see your point if signals were classified as either "ZF" ("zero
frequency") or "NZF" (non-zero frequency") but we are dealing with "DC"
or "AC"

If nothing else, your stubborn adherence to a flawed terminology and
lack of openness to furthering your understanding will make you look
like an idiot in a job interview, should you ever decide to pursue
career advancement in the electronics industry. Please note that I am
not saying you are an idiot, just that you will look like one in an
interview. The interviewers will assume you know very little about
the basics of the craft if you carry on like this, or at the very
least will see you as a detriment to teamwork. HTH.

--
Al Brennan

"If you only knew the magnificence of the 3, 6 and 9,
then you would have a key to the universe." Nicola Tesla

 

[William R. Walsh]

Hi!

So here's the question: what about this battery pack makes the
transformer heat up to the point it burns out? There doesn't seem to
be a short in the battery pack, just a few bad cells. . .I don't
understand why this gives the transformer such grief.

You do have some shorted cells and the charger is doing its best to charge
them up. It overheats as a result...probably because there is no (or very
little) current limiting taking place.

If you were to try charging the cells outside of the pack, you would
probably find that they get at least a little warm and that they don't hold
a charge for any appreciable length of time.

Will using this 24V charger on the 19.2V pack damage the charger or the
battery pack? I understand that this is a really cheap drill, but how
can they in good conscience provide a mismatched charger/pack? Is it
because 24V transformers are so cheap?

Anything is always possible, but there are certain safety exams any
electrical device must (or at least should) pass in almost every country of
the world. Supplying a mismatched charger would probably violate some of the
standards that any of these agencies have published or require by law.

It would be my guess that either the batteries were made to charge at a
higher voltage or that the regulation is done inside the battery pack
itself. I have a cheap spotlight that works this way. The adapter provided
with it is 12 volt, but the battery inside the unit is a 6 volt. There is a
printboard inside that contains the charger plug, a cut-out to keep the lamp
from being turned on while charging, and a large resistor that gets warm
during the charge process.

William

 

[daestrom]

"kinyo" <angkin2000@yahoo.com> wrote in message
news:1118595265.774501.117810@f14g2000cwb.googlegroups.com...

jackbruce9999@yahoo.com wrote:
snip
work for the DC Wave described? Will it output +5V or do negative peak
detectors only work for AC signals?

The circuit is pretty much unconventional (but sure smart!). No, it
will not output +5V. The circuit is meant to detect only negative
voltages and can only output zero or negative voltage. But I suggest
that your try building it and see what happens. You might just get
lucky.


Thank you.

You're welcome. I hope you now understand that your +5V to +15V voltage
is better called "varying DC". I've never seen an EE book that will say
"DC Sine Wave" for the voltage you described, and rightly so because a
sine wave implies reversing directions.

Or, one might refer to this as 10VDC with an AC waveform superimposed. The
AC waveform varies sinusoidally with 10 V peak-peak. One can then solve two
circuits, the DC one with just R and 10VDC, and the AC one with R-L-C.
Combining the currents from the two solutions should be equivalent to the
original circuit.

I agree, that 'DC sine wave' is a misnomer. It makes it sounds like the
speaker doesn't know AC from DC. In order to not sound foolish, it would be
better to use one of the alternatives suggested.

daestrom

 

[John Fields]

On Sun, 12 Jun 2005 13:30:26 -0700, Kitchen Man <nannerbac@yahoo.com>
wrote:

On Sun, 12 Jun 2005 14:33:39 -0500, John Fields
jfields@austininstruments.com> wrote:

On 12 Jun 2005 09:01:11 -0700, mabelmapleleaf@yahoo.com wrote:

It's a shame you have to weed thru all the crap from some
of the posters here who have a lot of time on their hands and
have no tolerance for those who are just learning their craft....

---
It's a shame that those of us who give of our time in an effort to
edify the ignorant are often abused by imbeciles who can't take
correction gracefully.

It is equally a shame that there are those that are sometimes
incapable of offering correction gracefully, eh, John? If it pains
you so much to engage in your ungracious edifying, perhaps you would
do well to bugger off, and leave the stress of educating imbeciles to
those with more patience.

---
Well, Al, correction (no matter how gently offered) is often met with
varying degrees of resistance, particularly by those who have become
convinced that their way should be temporarily accepted as the 'right'
way, for their convenience, regardless of whether their way conforms
to universally accepted standards.

Case in point, the OP, whose attitude seems to be (and I paraphrase)
"You know what I mean, so why should I have to say it your way?"

As for me, I'm perfectly capable of conducting myself politely in the
presence of polite company. I'm also perfectly capable of atrocious
behavior and have no qualms about stooping to that level if, in my
opinion, the situation warrants it.

Finally, I don't see how you came to the conclusion that it pains me
to engage in the edification of imbeciles. Actually, it's quite
gratifying to be able to take on the challenge of breaking through the
barrier of ignorance and realize that you've shown someone how to use
a tool they didn't even know they owned.


--
John Fields
Professional Circuit Designer

 

[John Fields]

On Sun, 12 Jun 2005 13:39:22 -0700, Kitchen Man <nannerbac@yahoo.com>
wrote:

On 10 Jun 2005 23:06:10 -0700, jackbruce9999@yahoo.com wrote:

You actually proved my
point that DC is DEFINED (i.e. by convention) as "zero frequency".
Is it that weird to posit that the superior concept with respect to
considering any signal as AC or DC, be the actual NET current flow? I
could see your point if signals were classified as either "ZF" ("zero
frequency") or "NZF" (non-zero frequency") but we are dealing with "DC"
or "AC"

If nothing else, your stubborn adherence to a flawed terminology and
lack of openness to furthering your understanding will make you look
like an idiot in a job interview, should you ever decide to pursue
career advancement in the electronics industry. Please note that I am
not saying you are an idiot, just that you will look like one in an
interview. The interviewers will assume you know very little about
the basics of the craft if you carry on like this, or at the very
least will see you as a detriment to teamwork. HTH.

---
His attitude, if he persists with it, will be a serious detriment no
matter what field of endeavor he chooses to enter.

Starting to see it my way, Al?-)

--
John Fields
Professional Circuit Designer

 

[Floyd L. Davidson]

"operator jay" <none@none.none> wrote:

"Floyd L. Davidson" <floyd@barrow.com> wrote in message
news:87mzpvzftb.fld@barrow.com...
"operator jay" <none@none.none> wrote:
"Floyd L. Davidson" <floyd@barrow.com> wrote in message
news:87y89fzqcu.fld@barrow.com...

The problem is that "direction" only has meaning when measured
in comparison some specific point of reference. If you have
three different reference points, one at the DC level, one at
the peak positive swing and one at the peak negative swing, you
have three very different views of "direction" for current flow:

Reference Direction
Point of flow
========= =====================================

Peak Pos All Negative

DC level Equal cycles of Positive and Negative

Peak Neg All Positive



I think "zero" is a good reference for current flow, and that the actual

Sure... now, can you define "zero"?


Put an ammeter there and it says zero. That's zero. Electrons bouncing
around in the conductor have an average net displacement, over time, of 0.

Is this an AC ammeter, or a DC ammeter? (And isn't that just a voltmeter
anyway, in most actual cases????) Hmmm...

(absolute) direction can be measured. Voltages have the reference
issues.

E =IR

You can't escape the fact that voltage and current are joined at
the hip, they are for all practical purposes different expressions
of the same thing. Whatever affects one *has* to have affected the
other.

Since our resistance is fixed, it's the exact same issue, though
perhaps easier to understand, with voltage. (I gave some
consideration as to whether to post that with voltage or current
references, and since "AC" and "DC" use the term "current",
decided to go with current to avoid the easier path to the same
statement you are making.)


Current is a different issue from voltage because voltage is a relative
quantity.

No more or less than current. They are joined at a hip called
Ohm's Law.

It is a type of measurement of a change in field between two
locations. Current is a rate of flow of charge at a single location (well,
typically, through a single Gaussian surface), and is measurable at that
location, and does not have the ambiguity that voltage has. It does not
need a reference. If I say that my toaster is running at 120V and 8A, you
may ask "120V relative to what" and I'll answer "neutral". You would not
ask "8A relative to what".

8 Amps from where? To where? Through were?

Relative to where?

Since we can discuss current using only voltage as the variable
(resistance being a constant in this example), *anything* you
can say about voltage is directly related to current.

One of the overall things that you *have* to keep in mind is
that periodic reality checks are necessary. One of them is the
fact, repeated by many in this thread, that "DC sine wave" is a
contradiction of terms. If your definition makes it possible,
your definition *can't* be right.

My point still stands, that if the current is changing, it is by
definition AC, and current not changing is DC. Trying to look
at it as DC is all in one direction and anything else is AC,
doesn't work.

--
Floyd L. Davidson <http://web.newsguy.com/floyd_davidson>
Ukpeagvik (Barrow, Alaska) floyd@barrow.com

 

[Don Lancaster]

Bob Penoyer wrote:

A rectified AC waveform contains DC and AC components but if the
current isn't changing direction, it isn't alternating current. And,
if it isn't AC, it's DC.

Total and utter horseshit.

"DC" is simply the first (or "offset" term in the Fourier expression of
any repetitive waveform.

"AC" are all of the remaining components.

Changing the relative amplitude of the terms does NOT in any manner
change which is the first term and which are the remaining terms.

DC, of course, cannot exist at all ever. Because it would have to be
unvarying through infinite time.

Tutorials on my website.



--
Many thanks,

Don Lancaster
Synergetics 3860 West First Street Box 809 Thatcher, AZ 85552
voice: (928)428-4073 email: don@tinaja.com

Please visit my GURU's LAIR web site at http://www.tinaja.com

 

[Floyd L. Davidson]

Don Lancaster <don@tinaja.com> wrote:

DC, of course, cannot exist at all ever. Because it would have
to be unvarying through infinite time.

Boy, you are *pedantic*!

Can't we just define DC as current that doesn't vary "much"
for at last a "long" time. Granted that is ambiguous, but
what else would we the argue about, weather?

--
Floyd L. Davidson <http://web.newsguy.com/floyd_davidson>
Ukpeagvik (Barrow, Alaska) floyd@barrow.com

 

[Floyd L. Davidson]

Kitchen Man <nannerbac@yahoo.com> wrote:

It is equally a shame that there are those that are sometimes
incapable of offering correction gracefully, eh, John? If it pains
you so much to engage in your ungracious edifying, perhaps you would
do well to bugger off, and leave the stress of educating imbeciles to
those with more patience.

Is patience required though?

I'm always reminded of a young lady I met once, many years ago
employed by Northern Telecom Inc to provide training on a
mainframe computer program to USAF personnel. This lady showed
up and started teaching the GI's, one at time. She first
latched onto a 16 year Staff Sargent (that suggests he might not
have been too bright). He'd been working with
telecommunications for all 16 of those years and didn't know
that a Class C Autovon line was the kind he could call home on
for free (every Airman figured that out in 6 days).

So, we thought the lady probably ought to be warned. And not
being a GI myself, it was sort of agreed that I'd tell her. We
had not counted on this lady being, ahem... perceptive. Not to
mention independent, ornery, and several other adjectives.

I hinted to her that the Sarge was the worst case example, and
maybe she shouldn't waste too much time on him. She growled at
me, and said something about my head and a dark place, and said
she had "A degree in teaching fucking idiots."

Apparently patience is not part of the requirement?

Somewhat ruffled at a gal 10 years younger than me getting the
best of me in that way, I decided to get back! There was this
almost friendly young Security Policeman who came by now and
then to check our credentials to be in a secure area. Of course
every SP lives for the day he can "jack up" somebody. So I
suggested we had a really good candidate to play games with! He
figured that was just a great idea, and followed me as I led him
to where he could perform this duty for his country.

But, alas, he came around the corner and this asshole young
lady looked at this asshole young Security Policeman, and he
looked at her... and I saw the look in their eyes and knew all
was lost. It was like in a movie! They locked on, you could
hear the bells ring! You could see them shiver! It was a
*classic* love at first sight! Danged guy spent the next *two*
*hours* talking to her, and they dated the entire time she was
there.

Patience... did teach me something!

--
Floyd L. Davidson <http://web.newsguy.com/floyd_davidson>
Ukpeagvik (Barrow, Alaska) floyd@barrow.com

 

[Arfa Daily]

I don't know where you would get the idea that your power was an upgrade on
ours. We NEVER EVER get brownouts here. This is largely because the higher
voltages we use on our crosscountry distribution network, allows for lower
transmission currents, which result in lower voltdrops at any resistance
points at junctions.

We can also run high watts appliances such as ovens and driers, without
having to use cables as thick as your arm, and 6 inch nails for fuses. Oh,
and we also did away with ugly overheads and pole mounted transformers at
street distribution level, years ago ....

So your system is an upgrade ?? Hmmmm ...


"Travis Jordan" <no.one@no.net> wrote in message
news:N6qpe.310405$H_1.12601@fe04.news.easynews.com...

owenocallaghan@hotmail.com wrote:
What would I need in order to adapt to the downgrade in electrical
power? Will it affect the sound quality? Any specific transformer
suggestion? And would the speakers be okay?

Don't know about the adaptation that is required (it could be as simple
as a different power cord or an adapter if the receiver will accept 120
VAC / 60 hz intead of limey power.

BTW, we here in the Colonies tend to think our power system is an
upgrade from 'yours'.

 

[John Fields]

On Sun, 12 Jun 2005 14:00:23 -0800, floyd@barrow.com (Floyd L.
Davidson) wrote:

My point still stands, that if the current is changing, it is by
definition AC, and current not changing is DC. Trying to look
at it as DC is all in one direction and anything else is AC,
doesn't work.

---
Your point is flawed. Alternating Current, by definition, causes
electrons to move in one direction for a time, and then to reverse
direction for a time.

The sinusoidally varying unipolar voltage under consideration _always_
forces electrons to move in one direction only.

Since the voltage varies, the current will also, but the _direction_
in which the electrons are travelling will never change.

That means that the signal is DC. A varying DC, but DC nonetheless.

--
John Fields
Professional Circuit Designer