sci.electronics.repair@googlegroups.com

Today's topics:

* Another reason to hate CFLs ... - 10 messages, 6 authors
http://groups.google.com/group/sci.electronics.repair/t/87ea27a2579f0316?hl=en
* OT: Is this question too challenging for a BSEE graduate? - 1 messages, 1
author
http://groups.google.com/group/sci.electronics.repair/t/31ba2b6a402a3720?hl=en
* Vox AD30VT small combo, 2007, PbF - 2 messages, 2 authors
http://groups.google.com/group/sci.electronics.repair/t/d5851d8e1a65198c?hl=en
* measuring ampermeter meter internal resistance - 7 messages, 5 authors
http://groups.google.com/group/sci.electronics.repair/t/27f050235cfa3de3?hl=en
* Testing SMPS Video - 1 messages, 1 author
http://groups.google.com/group/sci.electronics.repair/t/1cc72f0926af56cc?hl=en
* Phillips screw security bit? - 2 messages, 2 authors
http://groups.google.com/group/sci.electronics.repair/t/0dd92a1eef067d92?hl=en
* Sony Webbie white screen - 2 messages, 2 authors
http://groups.google.com/group/sci.electronics.repair/t/0ec5040a703ba2a4?hl=en

==============================================================================
TOPIC: Another reason to hate CFLs ...
http://groups.google.com/group/sci.electronics.repair/t/87ea27a2579f0316?hl=en
==============================================================================

== 1 of 10 ==
Date: Sun, Oct 24 2010 8:57 am
From: "William Sommerwerck"

> Over the years since this technology was vaunted as the
> 'replacement' for incandescent light, I have bought many
> examples from different manufacturers.

You've obviously had bad luck. Or there aren't any good ones in your neck of
the woods.

> They do not start up in the few ms that it takes an
> incandescent to come on...

True. They come on instantly. You can see the difference -- there's a
visible lag with incandescents.

> Neither do they reach full output for some considerable time
> after they're turned on.

Mine take about 30s. And they're acceptably from the moment they're turned .
(The older Philips were really dim at turn on.)

It appears that your government is aggressively forcing a conversion to CFLs
and other low-energy lighting. Forced conversion tends to short-circuit the
normal market forces that encourage companies to produce products people
really like. Your manufacturers have no real motivation to produce CFLs with
pleasing color balance.

== 2 of 10 ==
Date: Sun, Oct 24 2010 8:57 am
From: "Arfa Daily"

"Meat Plow" <mhywatt@yahoo.com> wrote in message
news:pan.2010.10.24.15.10.48@lmao.lol.lol...
> On Sun, 24 Oct 2010 02:28:14 +0100, Arfa Daily wrote:
>
>> As if any more reasons were needed on top of their horrible startup
>> characteristics, their ugliness, their sick coloured light, and their
>> inability to last for a fraction of the claimed lifetime :-(
>>
>> Like most of us, I suspect, I have hundreds of component drawers, which
>> over the years have become mixed up and confused, so in the
>> circumstances of work being very quiet at the moment, I decided to have
>> a major tidy up and clear out of redundant components. As a first move,
>> I decided to rationalise the resistors, and re-store them by individual
>> value, rather than in groups of values in the same drawer.
>>
>> Now the other day, the bulb in my Anglepoise bench light failed, and as
>> it was the last 60 watt pearl one I had - nowhere stocking such an
>> animal any more due to EU ecobollox intervention - I put in a CFL that
>> had come free in a cornflake packet or some such nonsense. Once it has
>> warmed up in the morning - at least one coffee drinking time needed for
>> this - it seemed to work reasonably well. Until, that is, I started
>> trying to identify the resistors in my old drawers to move them into the
>> individual value drawers in the new location.
>>
>> The spectrum from this lamp is so poor and discontinuous, that it is
>> almost impossible to resolve red from brown from orange, or violet from
>> blue or grey. Absolutely bloody useless. If I can't find any more 60
>> watt pearl bulbs on the 'net, then I'm going to modify the lampholder to
>> take a low voltage halogen downlighter bulb, and hook it to a 12v
>> transformer.
>>
>> Arfa
>
> I like the 6500k CFLs for security lighting and my bench light. I'm very
> surprised at the longevity of the outdoor 23 watters. They have been in
> use dusk to dawn in all kinds of weather, all mounted inverted and in
> some sort of shroud one actually totally enclosed in a globe. Only one
> has failed after two years and I expected it to fail, the globe enclosed
> CFL. None of these 4 outdoor lamps are rated for inverted use either. I
> did some reading on inverting a CFL and the base temperature increases
> dramatically when the lamp is inverted. So I would expect cheap
> electrolytics to dry up in no time.
>
>

But this totally underlines my point about them being a 'substitute' rather
than 'replacement' technology. Many many household fittings are either
enclosed, semi-enclosed, or use a bulb that hangs down. In fact I would have
to say that fittings that have the bulb base facing up, other than perhaps
in table lamps, are few and far between, and fittings that do employ such a
scheme, and are then able to take CFLs, are even rarer. My son has a
three-branch 'chandelier' fitting in his hallway. He has fitted CFLs to
this, and because of the larger bases that these have to accommodate the
ballast electronics, they stick out of the tops of the glass shades, and
look ridiculous.

Arfa

== 3 of 10 ==
Date: Sun, Oct 24 2010 9:46 am
From: Jeff Liebermann

On Sat, 23 Oct 2010 22:08:20 -0700, Jeff Liebermann <jeffl@cruzio.com>
wrote:

>On Sun, 24 Oct 2010 02:28:14 +0100, "Arfa Daily"
><arfa.daily@ntlworld.com> wrote:
>
>>Now the other day, the bulb in my Anglepoise bench light failed, and as it
>>was the last 60 watt pearl one I had - nowhere stocking such an animal any
>>more due to EU ecobollox intervention

More...

"Emission spectra of some compact fluorescent lamps"
<http://web.ncf.ca/jim/misc/cfl/>

You can check the spectra of some CFL lamps at:
<http://www.lamptech.co.uk/Compact%20Fluorescent.htm>

"The Double Amici Prism Hand-Held Spectroscope."
Emission spectra of various lamps are furthur down the page.
<http://ioannis.virtualcomposer2000.com/spectroscope/amici.html>
Incidentally, you might find it amusing to see what CCFL backlit white
looks like on a laptop LCD display [1.3.7], and a Sony Trinitron
[1.11.3]. Also, the authors comments on "Full-Spectrum Lamps" near
the bottom of the page.

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

== 4 of 10 ==
Date: Sun, Oct 24 2010 10:09 am
From: Jeff Liebermann

On Sun, 24 Oct 2010 09:50:24 +0100, "N_Cook" <diverse@tcp.co.uk>
wrote:

>These days fibre reinforced plastic or mineralised plastic, used to be
>ceramic in the original ones,

Reinforced Polybutylene Terephthalate (PBT) or Polyethylene
Terephthalate (PET) plastic resin with about 30% glass fiber mixed in
to minimally meet UL-94 V-0 flame retartent specs.

MSDS for CFL from Home Despot:
<http://www.homedepot.com/catalog/pdfImages/fd/fd8f96e1-4ff3-4a86-9070-e8583d3e636e.pdf>

>Googling for BU102 + TO92 gets nowhere, I
>assume as diac in there then triacs

What's inside and how it works:
"Self Oscillating 25W CFL Lamp Circuit"
<http://www.nxp.com/documents/application_note/AN00048.pdf>

Fiat Lux
(let there be light).

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

== 5 of 10 ==
Date: Sun, Oct 24 2010 10:12 am
From: Meat Plow

On Sun, 24 Oct 2010 16:57:42 +0100, Arfa Daily wrote:

> "Meat Plow" <mhywatt@yahoo.com> wrote in message
> news:pan.2010.10.24.15.10.48@lmao.lol.lol...
>> On Sun, 24 Oct 2010 02:28:14 +0100, Arfa Daily wrote:
>>
>>> As if any more reasons were needed on top of their horrible startup
>>> characteristics, their ugliness, their sick coloured light, and their
>>> inability to last for a fraction of the claimed lifetime :-(
>>>
>>> Like most of us, I suspect, I have hundreds of component drawers,
>>> which over the years have become mixed up and confused, so in the
>>> circumstances of work being very quiet at the moment, I decided to
>>> have a major tidy up and clear out of redundant components. As a first
>>> move, I decided to rationalise the resistors, and re-store them by
>>> individual value, rather than in groups of values in the same drawer.
>>>
>>> Now the other day, the bulb in my Anglepoise bench light failed, and
>>> as it was the last 60 watt pearl one I had - nowhere stocking such an
>>> animal any more due to EU ecobollox intervention - I put in a CFL
>>> that had come free in a cornflake packet or some such nonsense. Once
>>> it has warmed up in the morning - at least one coffee drinking time
>>> needed for this - it seemed to work reasonably well. Until, that is, I
>>> started trying to identify the resistors in my old drawers to move
>>> them into the individual value drawers in the new location.
>>>
>>> The spectrum from this lamp is so poor and discontinuous, that it is
>>> almost impossible to resolve red from brown from orange, or violet
>>> from blue or grey. Absolutely bloody useless. If I can't find any more
>>> 60 watt pearl bulbs on the 'net, then I'm going to modify the
>>> lampholder to take a low voltage halogen downlighter bulb, and hook it
>>> to a 12v transformer.
>>>
>>> Arfa
>>
>> I like the 6500k CFLs for security lighting and my bench light. I'm
>> very surprised at the longevity of the outdoor 23 watters. They have
>> been in use dusk to dawn in all kinds of weather, all mounted inverted
>> and in some sort of shroud one actually totally enclosed in a globe.
>> Only one has failed after two years and I expected it to fail, the
>> globe enclosed CFL. None of these 4 outdoor lamps are rated for
>> inverted use either. I did some reading on inverting a CFL and the base
>> temperature increases dramatically when the lamp is inverted. So I
>> would expect cheap electrolytics to dry up in no time.
>>
>>
>>
> But this totally underlines my point about them being a 'substitute'
> rather than 'replacement' technology. Many many household fittings are
> either enclosed, semi-enclosed, or use a bulb that hangs down. In fact I
> would have to say that fittings that have the bulb base facing up, other
> than perhaps in table lamps, are few and far between, and fittings that
> do employ such a scheme, and are then able to take CFLs, are even rarer.
> My son has a three-branch 'chandelier' fitting in his hallway. He has
> fitted CFLs to this, and because of the larger bases that these have to
> accommodate the ballast electronics, they stick out of the tops of the
> glass shades, and look ridiculous.
>
> Arfa

I wasn't arguing the fact that they are 'substitutes' as you put it. But
what is a person to do unless you are willing to blow your own glass and
buy tungsten from Norway or Sweden or wherever it comes from and
refurbish your own incandescents? You could start stockpiling your
favorite incandescents to have them on hand when they finally disappear
for good but what after that? Although fluorescents have been around for
60 years or more used in commercial lighting those that manufacture CFLs
are going to have to beef up the technology and design better lamps with
better quality components but keep the cost down at the same time.

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

== 6 of 10 ==
Date: Sun, Oct 24 2010 10:27 am
From: Meat Plow

http://tinyurl.com/2eqh6vp

GE hybrid CFL :)

== 7 of 10 ==
Date: Sun, Oct 24 2010 10:34 am
From: Jeff Liebermann

On Sun, 24 Oct 2010 16:57:42 +0100, "Arfa Daily"
<arfa.daily@ntlworld.com> wrote:

>But this totally underlines my point about them being a 'substitute' rather
>than 'replacement' technology. Many many household fittings are either
>enclosed, semi-enclosed, or use a bulb that hangs down. In fact I would have
>to say that fittings that have the bulb base facing up, other than perhaps
>in table lamps, are few and far between, and fittings that do employ such a
>scheme, and are then able to take CFLs, are even rarer. My son has a
>three-branch 'chandelier' fitting in his hallway. He has fitted CFLs to
>this, and because of the larger bases that these have to accommodate the
>ballast electronics, they stick out of the tops of the glass shades, and
>look ridiculous.

Agreed on all points. The lifetime of the CFL bulb seems to be
dramatically less if the bulb is enclosed in any manner (covered lamp
or reflector). See upper bar graph for 1,000 hr test at:
<http://www.lrc.rpi.edu/resources/newsroom/pdf/2007/PEARL8511.pdf>
80% of the bare bulbs made it past 1,000 hrs (which still sucks),
while only about 35% of the covered bulbs survived. If you run a lamp
for 6 hrs per day (evening only), then 1000 hrs is only about 6
months. Not exactly my idea of "long life" CFL bulbs, many of which
claim 6,000 to 15,000 hr lifetimes. If the 20% failure rate at 1,000
hrs figure is assumed, then after 5000 hrs, all of the test bulbs will
be dead.

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

== 8 of 10 ==
Date: Sun, Oct 24 2010 10:46 am
From: David Sanders

On Sun, 24 Oct 2010 09:46:06 -0700, Jeff Liebermann wrote:

> On Sat, 23 Oct 2010 22:08:20 -0700, Jeff Liebermann <jeffl@cruzio.com>
> wrote:
>
>>On Sun, 24 Oct 2010 02:28:14 +0100, "Arfa Daily"
>><arfa.daily@ntlworld.com> wrote:
>>
>>>Now the other day, the bulb in my Anglepoise bench light failed, and as it
>>>was the last 60 watt pearl one I had - nowhere stocking such an animal any
>>>more due to EU ecobollox intervention
>
> More...
>
> "Emission spectra of some compact fluorescent lamps"
> <http://web.ncf.ca/jim/misc/cfl/>
>
> You can check the spectra of some CFL lamps at:
> <http://www.lamptech.co.uk/Compact%20Fluorescent.htm>
>
> "The Double Amici Prism Hand-Held Spectroscope."
> Emission spectra of various lamps are furthur down the page.
> <http://ioannis.virtualcomposer2000.com/spectroscope/amici.html>
> Incidentally, you might find it amusing to see what CCFL backlit white
> looks like on a laptop LCD display [1.3.7], and a Sony Trinitron
> [1.11.3]. Also, the authors comments on "Full-Spectrum Lamps" near
> the bottom of the page.

But can it grow superb colas?
--
Shit! I thought no one knew, goddammit!
http://preview.tinyurl.com/29p4ody
Me, jacking off! http://preview.tinyurl.com/3xpntge Available For
Lessons!

== 9 of 10 ==
Date: Sun, Oct 24 2010 10:37 am
From: Rich Webb

On Sun, 24 Oct 2010 09:46:06 -0700, Jeff Liebermann <jeffl@cruzio.com>
wrote:

>On Sat, 23 Oct 2010 22:08:20 -0700, Jeff Liebermann <jeffl@cruzio.com>
>wrote:
>
>>On Sun, 24 Oct 2010 02:28:14 +0100, "Arfa Daily"
>><arfa.daily@ntlworld.com> wrote:
>>
>>>Now the other day, the bulb in my Anglepoise bench light failed, and as it
>>>was the last 60 watt pearl one I had - nowhere stocking such an animal any
>>>more due to EU ecobollox intervention
>
>More...
>
>"Emission spectra of some compact fluorescent lamps"
><http://web.ncf.ca/jim/misc/cfl/>
>
>You can check the spectra of some CFL lamps at:
><http://www.lamptech.co.uk/Compact%20Fluorescent.htm>
>
>"The Double Amici Prism Hand-Held Spectroscope."
>Emission spectra of various lamps are furthur down the page.
><http://ioannis.virtualcomposer2000.com/spectroscope/amici.html>
>Incidentally, you might find it amusing to see what CCFL backlit white
>looks like on a laptop LCD display [1.3.7], and a Sony Trinitron
>[1.11.3]. Also, the authors comments on "Full-Spectrum Lamps" near
>the bottom of the page.

Cool stuff. Always interesting to "see" that what we perceive is not
always (or often) 1:1 with what's really there.

Make Magazine vol 24 (due out any day now) will have a DIY article on a
hand-held diffraction grating spectroscope.
http://makezine.com/magazine/ (Note that as of today the link shows
volume 23; subscribers should have received an email link to number 24).

There's also http://sciencefirst.com/product_info.php?products_id=403.
It's kind of clunky (basically a kid's toy) but it does have an
adjustable scale so it can be kinda-sorta calibrated using a known
spectral line from a fluorescent lamp.

--
Rich Webb Norfolk, VA

== 10 of 10 ==
Date: Sun, Oct 24 2010 10:54 am
From: "William Sommerwerck"

> http://tinyurl.com/2eqh6vp
> GE hybrid CFL :)

Bad, bad idea. That halogen bulb is not going to last very long.

==============================================================================
TOPIC: OT: Is this question too challenging for a BSEE graduate?
http://groups.google.com/group/sci.electronics.repair/t/31ba2b6a402a3720?hl=en
==============================================================================

== 1 of 1 ==
Date: Sun, Oct 24 2010 9:00 am
From: "Proteus"

"Michael A. Terrell" <mike.terrell@earthlink.net> wrote in message
news:HaKdnQ3UkO1WzV_RnZ2dnUVZ_vednZ2d@earthlink.com...
>
> RosemontCrest wrote:
>>
>> I routinely use the following question to test candidates for EE or TE
>> positions. For many years, it continues to stump all but one of many.
>> Is it really that difficult to solve?
>>
>> http://smg.photobucket.com/albums/v18/RosemontCrest/?action=view&current=programmableload.jpg
>>
>> or
>>
>> http://preview.tinyurl.com/2c8udf9
>>
>> I see two ways to solve it. The preferred method is to use Ohm's law
>> and nodal analysis without regard to the value of +VDC. Another method
>> is to assign a value to +VDC and solve it that way; I find that method
>> lame. Is this question, or test, too challenging for a BSEE graduate?
>>
>> For entertainment only, I invite any of you to provide the solution
>> using only nodal analysis without consideration of the value of +VDC
>> (showing or explaining your work). There are bonus points that have no
>> value for calculating the exact equivalent resistance.
>
>
> Then make your challenge on the proper newsgroup:
> news:sci.electronics.design which is where you'll find the EEs.
>
>
> --
> Politicians should only get paid if the budget is balanced, and there is
> enough left over to pay them.

FREAK! STOP POLICING ASSHOLE.

YOUR JOHN FOOL AND YOU ARE ABOUT THE SAME IN TECHNOLOGY, JOHN IS GOOD AT
COPY AND PASTE HIS FUCKING COPIED CAPACITOR FORMULA. KEEP FOLLOWING EACH
OTHER SKUNK!

I AM PROTEUS

==============================================================================
TOPIC: Vox AD30VT small combo, 2007, PbF
http://groups.google.com/group/sci.electronics.repair/t/d5851d8e1a65198c?hl=en
==============================================================================

== 1 of 2 ==
Date: Sun, Oct 24 2010 9:06 am
From: "Arfa Daily"

"Meat Plow" <mhywatt@yahoo.com> wrote in message
news:pan.2010.10.24.15.13.11@lmao.lol.lol...
> On Sun, 24 Oct 2010 01:48:02 +0100, Arfa Daily wrote:
>
>> On 23/10/2010 16:37, Meat Plow wrote:
>>> On Sat, 23 Oct 2010 02:11:15 +0100, Arfa Daily wrote:
>>>
>>>> "N_Cook"<diverse@tcp.co.uk> wrote in message
>>>> news:i9s9fu$jr$1@news.eternal-september.org...
>>>>> In the end it was duff PbF solder meeting 50 yearold technology, the
>>>>> pcb-type pins of the valveholder. After redoing solder could simulate
>>>>> the reported previous intermittant situation of half power and no
>>>>> power by hovering a variously angled hot valve over the socket pins.
>>>>> The 2 cathodes are tied to -15V , beyond that quite complex, traces
>>>>> to njm2082 dual FET opamp and the DG211 an. sw. etc, certainly no
>>>>> proper anode Vs
>>>>>
>>>>>
>>>>>
>>>> Do you have a schematic for it ? This Vox is pretty similar
>>>>
>>>> http://www.blueguitar.org/new/schem/misc_amp/vox_vr30reverb.pdf
>>>>
>>>> and also uses a 12AX7 with an anode supply of just 15v, and it does
>>>> appear to be configured as a conventional genuine amplifier stage. I
>>>> seem to recall Elektor magazine doing some stuff with ECC / 12AX
>>>> series twin triodes. operating with low anode voltages.
>>>>
>>>> Arfa
>>>
>>> Don't they call that a starved cathode configuration?
>>>
>>>
>>>
>> Starved anode, I think.
>>
>> Arfa
>
> Hmmm makes sense but there is another mode they run these effects units
> in that utilize a 12AX7 called starved cathode. Unless I'm completely
> mistaken.
>
>
I have seen a number of effects pedals that use a 12AX7 with a very low
anode voltage applied, to make deliberate (effects) use of the non linearity
of the anode characteristic that this produces. However, what this is called
as a technique, I've really no idea.

I just looked up the term "starved cathode" and it does appear to refer to
the same non linear effect achieved with very low anode voltages, so maybe
it's just a case of which angle you look at it from, as to whether to call
it starved anode, or cathode. Prior to this discussion, I had only ever
heard it referred to as anode.

Arfa

== 2 of 2 ==
Date: Sun, Oct 24 2010 10:21 am
From: Meat Plow

On Sun, 24 Oct 2010 17:06:08 +0100, Arfa Daily wrote:

> "Meat Plow" <mhywatt@yahoo.com> wrote in message
> news:pan.2010.10.24.15.13.11@lmao.lol.lol...
>> On Sun, 24 Oct 2010 01:48:02 +0100, Arfa Daily wrote:
>>
>>> On 23/10/2010 16:37, Meat Plow wrote:
>>>> On Sat, 23 Oct 2010 02:11:15 +0100, Arfa Daily wrote:
>>>>
>>>>> "N_Cook"<diverse@tcp.co.uk> wrote in message
>>>>> news:i9s9fu$jr$1@news.eternal-september.org...
>>>>>> In the end it was duff PbF solder meeting 50 yearold technology,
>>>>>> the pcb-type pins of the valveholder. After redoing solder could
>>>>>> simulate the reported previous intermittant situation of half
>>>>>> power and no power by hovering a variously angled hot valve over
>>>>>> the socket pins. The 2 cathodes are tied to -15V , beyond that
>>>>>> quite complex, traces to njm2082 dual FET opamp and the DG211 an.
>>>>>> sw. etc, certainly no proper anode Vs
>>>>>>
>>>>>>
>>>>>>
>>>>> Do you have a schematic for it ? This Vox is pretty similar
>>>>>
>>>>> http://www.blueguitar.org/new/schem/misc_amp/vox_vr30reverb.pdf
>>>>>
>>>>> and also uses a 12AX7 with an anode supply of just 15v, and it does
>>>>> appear to be configured as a conventional genuine amplifier stage. I
>>>>> seem to recall Elektor magazine doing some stuff with ECC / 12AX
>>>>> series twin triodes. operating with low anode voltages.
>>>>>
>>>>> Arfa
>>>>
>>>> Don't they call that a starved cathode configuration?
>>>>
>>>>
>>>>
>>> Starved anode, I think.
>>>
>>> Arfa
>>
>> Hmmm makes sense but there is another mode they run these effects units
>> in that utilize a 12AX7 called starved cathode. Unless I'm completely
>> mistaken.
>>
>>
> I have seen a number of effects pedals that use a 12AX7 with a very low
> anode voltage applied, to make deliberate (effects) use of the non
> linearity of the anode characteristic that this produces. However, what
> this is called as a technique, I've really no idea.
>
> I just looked up the term "starved cathode" and it does appear to refer
> to the same non linear effect achieved with very low anode voltages, so
> maybe it's just a case of which angle you look at it from, as to whether
> to call it starved anode, or cathode. Prior to this discussion, I had
> only ever heard it referred to as anode.
>
> Arfa

LOL I've only heard it referred to as starved cathode :) My Peavey Tube
FEX uses two 12AX7's for gain and tube effects. I'm sure they run in a
starved mode. Worked on a Mesa Boogie tube pedal with a 12AX7 in it that
ran off a 12 volt wart. If you want some tube sound and gain the Mesa is
the way to go although you'll pay a pretty penny for a vintage model.

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

==============================================================================
TOPIC: measuring ampermeter meter internal resistance
http://groups.google.com/group/sci.electronics.repair/t/27f050235cfa3de3?hl=en
==============================================================================

== 1 of 7 ==
Date: Sun, Oct 24 2010 9:08 am
From: "PeterD"

"John Fields" <jfields@austininstruments.com> wrote in message
news:etd8c65us8t07qqnst4l8pbmr26dpiolfq@4ax.com...
> On Sat, 23 Oct 2010 22:14:42 -0700, Jeff Liebermann <jeffl@cruzio.com>
> wrote:
>
>>On Sat, 23 Oct 2010 21:31:15 -0700, "John Fields"
>><jfields@austininstruments.com> wrote:
>>
>>>No Stupid, that's not the way to ampmeter range to higher range. Why did
>>>you call yourself Superpower Punk? You don't even know how to multiple
>>>the
>>>power of your electronic? You see, I am a superdumb-ass and I am very
>>>capable to multiple current as well as AmpMeter by 10X.
>>>JF
>>
>>New York Makes Internet Impersonation a Crime
>><http://www.hunton.com/files/tbl_s10News/FileUpload44/15889/new_york_internet_impersonation_privacy_alert.pdf>
>>
>>California Bans Malicious Online Impersonation
>><http://www.pcworld.com/businesscenter/article/206469/california_bans_malicious_online_impersonation.html>
>>
>>etc...
>
> ---
> Thanks for that, and now that I have Mr. I'm-not-all-that-bright's ISP
> listed on the header he forged _and_ his real-world name and address
> it shouldn't be long before he'll be thinking every little sound he
> hears is the NYPD knocking on his door. :-)
>
> ---
> JF

Yup, trace his ass John and let me know your success.

== 2 of 7 ==
Date: Sun, Oct 24 2010 9:37 am
From: Fred Abse

On Sun, 24 Oct 2010 08:53:52 -0700, Proteus wrote:

>
> "Fred Abse" <excretatauris@invalid.invalid> wrote in message
> news:pan.2010.10.24.09.53.04.370083@invalid.invalid...
>> On Sat, 23 Oct 2010 21:31:15 -0700, someone calling himself "John Fields"
>> wrote:
>>
>>> No Stupid, that's not the way to ampmeter range to higher range. Why did
>>> you call yourself Superpower Punk? You don't even know how to multiple
>>> the
>>> power of your electronic? You see, I am a superdumb-ass and I am very
>>> capable to multiple current as well as AmpMeter by 10X.
>>
>>
>> What a lousy impersonation.
>>
>> The John Fields that we all know (and love?) writes grammatically.
>>
>> --
>> "For a successful technology, reality must take precedence
>> over public relations, for nature cannot be fooled."
>> (Richard Feynman)
>
> YOU ARE MORE FUCK-UP ASSHOLE FREAK!
>
> I AM PROTEUS

http://maps.google.com/maps?ll=60.2631,-1.407736&spn=0.1,0.1&t=m&q=60.2631,-1.407736

Plonk!

--
"For a successful technology, reality must take precedence
over public relations, for nature cannot be fooled."
(Richard Feynman)

== 3 of 7 ==
Date: Sun, Oct 24 2010 10:01 am
From: Paul Keinanen

On Sat, 23 Oct 2010 21:28:15 -0700 (PDT), mynick <anglomont@yahoo.com>
wrote:

>want to shunt a multimeter to extend it's ac ampermeter range so
>measured with Rish 14s

So good so far.

According to the link the voltage drop is 270 mV at 10 A current.
This should not be hard to calculate the internal resistor of the
multimeter based of this information :-)

>in ohm meter position about 41 ohms
>and then measured with Rish 14s its own internal resistance to get 40
>ohms
>Is this way to much -there is some mistake?

Those values do not make any sense for any realistic current meter
(except for some extremely low current applications).

>(http://www.multimetercalibrationsaustralia.com.au/rishmulti14s.pdf
> but cannot find data about it's internal resistance!)

For your own safety, if the 10 Aac current range of the multimeter is
not enough, please consider using a current transformer for measuring
large 50/60 Hz currents.

And remember that with current transformers, the secondary must
_always_ be shorted or connected to a low impedance meter.

== 4 of 7 ==
Date: Sun, Oct 24 2010 10:11 am
From: "PeterD"

"Paul Keinanen" <keinanen@sci.fi> wrote in message
news:mmo8c6he45f47n3h0vgq2on9099us46r1u@4ax.com...
> On Sat, 23 Oct 2010 21:28:15 -0700 (PDT), mynick <anglomont@yahoo.com>
> wrote:
>
>>want to shunt a multimeter to extend it's ac ampermeter range so
>>measured with Rish 14s
>
> So good so far.
>
> According to the link the voltage drop is 270 mV at 10 A current.
> This should not be hard to calculate the internal resistor of the
> multimeter based of this information :-)
>
>>in ohm meter position about 41 ohms
>>and then measured with Rish 14s its own internal resistance to get 40
>>ohms
>>Is this way to much -there is some mistake?
>
> Those values do not make any sense for any realistic current meter
> (except for some extremely low current applications).
>
>>(http://www.multimetercalibrationsaustralia.com.au/rishmulti14s.pdf
>> but cannot find data about it's internal resistance!)
>
> For your own safety, if the 10 Aac current range of the multimeter is
> not enough, please consider using a current transformer for measuring
> large 50/60 Hz currents.
>
> And remember that with current transformers, the secondary must
> _always_ be shorted or connected to a low impedance meter.
>

Oh my Gosh, you are really Stupid. Stop using internal resistance to expand
Amp meter Dumbass. It's not the way to do it fucker.

Your 0.270a to overcomde the accurancy of 10A? No wonder why you are too
Superdumb.

If you do the right thing, you can turn a 10A meter into 100A meter with
0.02% error.

Why should I tell you Superpower? You should know it if you are really what
you believe you are. Ok numbass?

== 5 of 7 ==
Date: Sun, Oct 24 2010 11:01 am
From: Jamie

Paul Keinanen wrote:

> On Sat, 23 Oct 2010 21:28:15 -0700 (PDT), mynick <anglomont@yahoo.com>
> wrote:
>
>
>>want to shunt a multimeter to extend it's ac ampermeter range so
>>measured with Rish 14s
>
>
> So good so far.
>
> According to the link the voltage drop is 270 mV at 10 A current.
> This should not be hard to calculate the internal resistor of the
> multimeter based of this information :-)
>
>
>>in ohm meter position about 41 ohms
>>and then measured with Rish 14s its own internal resistance to get 40
>>ohms
>>Is this way to much -there is some mistake?
>
>
> Those values do not make any sense for any realistic current meter
> (except for some extremely low current applications).
>
>
>>(http://www.multimetercalibrationsaustralia.com.au/rishmulti14s.pdf
>>but cannot find data about it's internal resistance!)
>
>
> For your own safety, if the 10 Aac current range of the multimeter is
> not enough, please consider using a current transformer for measuring
> large 50/60 Hz currents.
>
> And remember that with current transformers, the secondary must
> _always_ be shorted or connected to a low impedance meter.
>
Oh why did you have to tell him the last part! :)

== 6 of 7 ==
Date: Sun, Oct 24 2010 11:02 am
From: Jeff Liebermann

On Sun, 24 Oct 2010 08:49:42 -0500, John Fields
<jfields@austininstruments.com> wrote:

He's in California. He's posting from 66.53.26.169 which RDNS
resolves to 66-53-26-169.lvgs.mdsg-pacwest.com, which is the dialup
modem pool in Stockton, Calif. His message was posted through
Toast.net, which is probably his ISP. There's a valid X-Trace header
included. This is too easy. What I find personally amusing is that
he's using Outlook Express for reading Usenet news, which suggests
that he's clueless. Judging by the writing style, I would guess about
17 years old.

$1000 fine and you can sue for damages to your reputation.
<http://www.leginfo.ca.gov/pub/09-10/bill/sen/sb_1401-1450/sb_1411_bill_20100927_chaptered.html>

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

== 7 of 7 ==
Date: Sun, Oct 24 2010 11:19 am
From: Jamie

Jeff Liebermann wrote:

> On Sun, 24 Oct 2010 08:49:42 -0500, John Fields
> <jfields@austininstruments.com> wrote:
>
> He's in California. He's posting from 66.53.26.169 which RDNS
> resolves to 66-53-26-169.lvgs.mdsg-pacwest.com, which is the dialup
> modem pool in Stockton, Calif. His message was posted through
> Toast.net, which is probably his ISP. There's a valid X-Trace header
> included. This is too easy. What I find personally amusing is that
> he's using Outlook Express for reading Usenet news, which suggests
> that he's clueless. Judging by the writing style, I would guess about
> 17 years old.
>
> $1000 fine and you can sue for damages to your reputation.
> <http://www.leginfo.ca.gov/pub/09-10/bill/sen/sb_1401-1450/sb_1411_bill_20100927_chaptered.html>
>
In CA, you can sue for anything...

Actually, I can get sued for what I just said! Because its definition
of character for CA :)

==============================================================================
TOPIC: Testing SMPS Video
http://groups.google.com/group/sci.electronics.repair/t/1cc72f0926af56cc?hl=en
==============================================================================

== 1 of 1 ==
Date: Sun, Oct 24 2010 10:17 am
From: Meat Plow

On Mon, 25 Oct 2010 00:14:19 +0900, Michael Kennedy wrote:

> Here is a video of this thing clicking while warming up and cooling off.
>
> http://www.youtube.com/watch?v=ckW8XSZ7T4A
>
> http://www.youtube.com/watch?v=urx3JrsxFmo
>
> I have gone through this thing with my ESR meter and havent found any
> bad caps. I changed some suspect caps because of their location near hot
> resistors. To make things more difficult the inside of this tv is
> coated with cigarrette tar... So some caps and things look blackened but
> in reality its form smoke residue..
>
>
> by the way thank you everyone who has made a suggestion on this. I am
> very thankful everyone here is so supportive to amatures like myself..

My 32" LCD makes all kind of clicking noises while it warms up and
especially when it cools off after it is shut off. But it is mechanical
noise from the expansion and contraction of heated surfaces. Are you sure
you're not hearing some of this?

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

==============================================================================
TOPIC: Phillips screw security bit?
http://groups.google.com/group/sci.electronics.repair/t/0dd92a1eef067d92?hl=en
==============================================================================

== 1 of 2 ==
Date: Sun, Oct 24 2010 10:37 am
From: AZ Nomad

On Mon, 18 Oct 2010 15:42:40 -0400, Rich Webb <bbew.ar@mapson.nozirev.ten> wrote:
>On Mon, 18 Oct 2010 12:09:59 -0700, "David Farber"
><farberbear.unspam@aol.com> wrote:

>>I'm trying to disassemble a Kill-A-Watt P4460. A device that was plugged
>>into it had some electrical problem and caused the circuit breaker in my
>>house to trip. When I removed the Kill-A-Watt from the ac outlet, the ground
>>pin had a nice burn mark on it and now the display is dead. There are three
>>Phillips screws on the back of the unit but one of them appears to have one
>>of those raised points in the center of it which prevent you from putting in
>>a regular bit. I cannot find any security tool in my collection that fits
>>this type of screw. I'm not even sure what to search for online. The screw
>>looks like a torx bit but it only has four notches. Any idea what tool fits
>>this?

>Hmmm. Just checked the back of the 4460 here and all three screw heads
>are Philips. It's a few years old, though, so maybe their lawyers got
>involved or something.

>Regardless, I wonder if a "spanner security bit" would work here? It's
>shaped rather like a regular flat-bladed screwdriver but with a notch in
>the center. You could probably make one by sizing a small flatblade with
>one of the other screws and grinding a notch in the center.

For a device like the kill-o-watt, just grab the screws with a sharp pair of
diagonal cutters and turn. Then use needlenose pliars to finish turning the
screws out. That POS isn't worth a $5 tool investment.

Or are they recessed? Tapping a sharp standard screwdriver with a hammer till it
bites would do the trick.

== 2 of 2 ==
Date: Sun, Oct 24 2010 11:09 am
From: Jamie

AZ Nomad wrote:

> On Mon, 18 Oct 2010 15:42:40 -0400, Rich Webb <bbew.ar@mapson.nozirev.ten> wrote:
>
>>On Mon, 18 Oct 2010 12:09:59 -0700, "David Farber"
>><farberbear.unspam@aol.com> wrote:
>
>
>>>I'm trying to disassemble a Kill-A-Watt P4460. A device that was plugged
>>>into it had some electrical problem and caused the circuit breaker in my
>>>house to trip. When I removed the Kill-A-Watt from the ac outlet, the ground
>>>pin had a nice burn mark on it and now the display is dead. There are three
>>>Phillips screws on the back of the unit but one of them appears to have one
>>>of those raised points in the center of it which prevent you from putting in
>>>a regular bit. I cannot find any security tool in my collection that fits
>>>this type of screw. I'm not even sure what to search for online. The screw
>>>looks like a torx bit but it only has four notches. Any idea what tool fits
>>>this?
>
>
>>Hmmm. Just checked the back of the 4460 here and all three screw heads
>>are Philips. It's a few years old, though, so maybe their lawyers got
>>involved or something.
>
>
>>Regardless, I wonder if a "spanner security bit" would work here? It's
>>shaped rather like a regular flat-bladed screwdriver but with a notch in
>>the center. You could probably make one by sizing a small flatblade with
>>one of the other screws and grinding a notch in the center.
>
>
> For a device like the kill-o-watt, just grab the screws with a sharp pair of
> diagonal cutters and turn. Then use needlenose pliars to finish turning the
> screws out. That POS isn't worth a $5 tool investment.
>
> Or are they recessed? Tapping a sharp standard screwdriver with a hammer till it
> bites would do the trick.
Or, you can go to a place like Harborfrieght and get a large set for
cheap which has that fork tungue bit in it of various sizes..

http://www.harborfreight.com/catalogsearch/result?category=&q=security+bits

==============================================================================
TOPIC: Sony Webbie white screen
http://groups.google.com/group/sci.electronics.repair/t/0ec5040a703ba2a4?hl=en
==============================================================================

== 1 of 2 ==
Date: Sun, Oct 24 2010 10:46 am
From: AtomicTom

I have used my Sony Webbie HD MHS-CM1 for several years with no
problems.
Recently, when I turn it on I only get a white screen,
Once out of every 100 times I turn it on the screen info will appear,
but after about 20 seconds the screen will white out.
I tried the Sony factory pin hole reset with no results.
I can retrieve the data on the flash via the USB port.
The battery charges, with the power input
The camera makes all the appropiate sounds when turned on as if it
were working but only a white screen.

Thank you

== 2 of 2 ==
Date: Sun, Oct 24 2010 10:49 am
From: David Sanders

On Sun, 24 Oct 2010 10:46:39 -0700 (PDT), AtomicTom wrote:

> I have used my Sony Webbie HD MHS-CM1 for several years with no
> problems.
> Recently, when I turn it on I only get a white screen,
> Once out of every 100 times I turn it on the screen info will appear,
> but after about 20 seconds the screen will white out.
> I tried the Sony factory pin hole reset with no results.
> I can retrieve the data on the flash via the USB port.
> The battery charges, with the power input
> The camera makes all the appropiate sounds when turned on as if it
> were working but only a white screen.
>
> Thank you

It's fucked, buy a new one.
--
Shit! I thought no one knew, goddammit!
http://preview.tinyurl.com/29p4ody
Me, jacking off! http://preview.tinyurl.com/3xpntge Available For
Lessons!

==============================================================================

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