Toshiba TV29C90 problem; Image fades to black...

[Dave Martindale]

Ian Jackson <IanJackson@REMOVE-THIS-BITg3ohx.demon.co.uk> writes:

Equally bad on ethernet I expect? Also, does ethernet require them to be
non-directional (ie just resistive tap-offs, with no directional
coupler)?

Ethernet required a direct connection to the conductor of the cable, if
I remember correctly. The receiver side was high impedance, so it
didn't present a significant load to the signal, and the vampire tap was
designed to create only a small hole through the shield and inner
dielectric so it wouldn't produce much of an impedance bump. Plus the
cable was marked with rings to indicate where you could put a tap
without having multiple taps end up a multiple of a wavelength apart.

When transmitting, an Ethernet transceiver acted as a current source,
putting a fair bit of current into the 25 ohm load (50 ohm cable heading
off in each of 2 directions). If two transceivers decided to transmit
at the same time, the high DC level on the cable was used to detect a
collision.

Original Ethernet used a baseband signal, and on a moderate-sized
network every station listened to every other one directly. There's no
"head end" to echo upstream signals back downstream again. There's no
notion of "upstream" and "downstream".

Dave

 

[Michael A. Terrell]

Ian Jackson wrote:

In message <4672E270.D2536F3D@earthlink.net>, Michael A. Terrell
mike.terrell@earthlink.net> writes
Ian Jackson wrote:


I'm in the CATV industry, and I've just remembered that, many years ago,
I did see reference to 'vampire taps' as being the latest and greatest
for coaxial ethernet. That took me back to the early 1960s, when similar
tap devices were manufactured in the UK (by Thorn, I think). I may still
have one somewhere. Nasty things!

Here, they were called "Stinger taps" and I had an unused tap block and
stinger, along with the strand clamp and drop hook in my toolbox, until
at least 2001. It might still be around, but I haven't used that toolbox
in so many years that i don't remember. I brought it home the day i was
laid off, then I was declared disabled, and unable to work, so it has
been under one of my benches here at home, ever since.

They were real low grade shit. They were replaced by backmatched
taps when systems were extended past the original 12 channel systems in
the US. They caused mismatch problems, and wasted a lot of the signal
on the trunklines or feeders. They worked, more or less on systems with
just a few channels, and very few customers, but them, those people were
already used to ghosting and snow. They had all been pulled from the 17
systems around Ft Rucker by 1972, including a couple short haul feeds
that only had a couple channels.


Equally bad on ethernet I expect? Also, does ethernet require them to be
non-directional (ie just resistive tap-offs, with no directional
coupler)?

Actually, there are two types of coaxial networking that used 75 ohm
cable. The simple, small network like Dave describes below witch were
non directional, and one that is usually part of a community loop where
pairs of one forward channel, and one return channel are used for data,
with a heterodyne signal processor at the headend to upconvert the
return channel to a forward channel witch is built with back matched
taps.

This system predates the current cable modems, but used standard, off
the shelf CATV components to build a private WAN along with the RF
modems. Some were mixed systems, of RF fed to clusters of the simpler
coaxial networking. The first system like that I heard about was the
Ohio State University campus in the '70s or early '80s. Their private
CATV system connected all the buildings, then tied the existing, smaller
networks together. I met two of their IT people at a hamfest, and they
were bragging about their design, till I told them about the systems I
maintained for the US army, years earlier. There was no return channel
equipment on the market, so we had a pair of 12 channel 'Vicoa' (Later
called Coral) systems set up as forward and return to carry the weather
data from an airfield to the main base where it added to the other nine
forward channels that fed the classrooms and airfield ready rooms.

We also built the first emergency alert system into a CATV system
that took control of the civilian CATV service to the barracks and on
base housing. A custom made coaxial relay was added to the existing
system to seize control of the private system. The ETV studio was 12
channel, like the civilian system. A toggle switch (with a hinged cover
and a lead seal) would feed the same audio and video to all 12
modulators, and switch the remote relay so an alert could be spread, no
matter what channel a TV was on. After we proved the concept, it
quickly spread to other bases, and new builds of civilian systems. The
last system I maintained was a 36 channel RCA headend, in the early
'80s. It had the optional IF loop through and auxiliary IF input for
the alert system. The Audio and video was fed through a separate
modulator with a IF output amp, instead of a channel module. I rewired
the rack by strapping the loss of signal output to the relay control,
and connected diodes to isolate each channel from the emergency control
system. I also looped the emergency video through the local access
control room so I could flip one switch and feed the same signal to all
36 channels in an emergency.

The loss of signal mod caused a message to appear a half second after
the carrier dropped out from a TV station, or satellite feed. That let
the tech on night shift check the alignment of the converters after
stations signed off, at night.

--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

 

[Don Klipstein]

In article <46747B68.69CF75EB@earthlink.net>, Michael A. Terrell wrote:

(Snipped because I found it less-relevant-than-I-expected to the subject
line)

I was expecting to see stuff about power consumption by "wall warts".

Those have been called "vampires" by being 2-pronged/"fanged" constant
consumers of small amounts of electrical energy that can become somewhat
significant in terms of electrical energy consumption if one has several
being powered 24/7, though this is well behind a refrigerator and behind
most climte control and lighting electricity demand.

I do believe that there should be some "energy efficiency" requirements
of those.
I find many "switchmode" cell phone chargers to do well in that area, as
I estimate from their heat output when loaded (mostly somewhat less than
that of wallwarts" with iron core physical transformers) and when
unloaded or largely-unloaded (they become outright cool to the touch when
being connected to a cellphone that has detected that its battery got
fully charged).

I also see many "wallwarts" with more-traditional iron core transformers
easily consuming a watt or two less apiece if they get made with heavier
gauge wire, more turns of wire per unit area of
wound-around-core-cross-section, and/or thinner core material laminations
preferably of some decent material - preferably "29M6" or only one or two
minor steps cheaper than that. Maybe requiring next larger size (usually
step up in most-traditional inch measurements for an "E-I" transformer
core has longest dimension upped 5/16 inch, another upped 1/4 inch
and the third upped 1/8 inch, and there are often some options to more
mildly increase only the "stack thickness" of a laminated core by 1/8 inch
that will even alone fairly often do well).

- Don Klipstein (don@misty.com)

 

[Ian Jackson]

In message <slrnf793na.8dk.don@manx.misty.com>, Don Klipstein
<don@manx.misty.com> writes

In article <46747B68.69CF75EB@earthlink.net>, Michael A. Terrell wrote:



I was expecting to see stuff about power consumption by "wall warts".

Those have been called "vampires" by being 2-pronged/"fanged" constant
consumers of small amounts of electrical energy



That may explain why they haven't become known as 'vampires' in the UK.

Everything which plugs into a wall socket has to have THREE pins. The
live and neutral receptacles have safety shutters, which are moved aside
as the ground pin (which is somewhat longer) enters. Even in the UK, no
self-respecting vampire would use three teeth.
Ian.
--

 

[Michael A. Terrell]

Don Klipstein wrote:

In article <46747B68.69CF75EB@earthlink.net>, Michael A. Terrell wrote:

(Snipped because I found it less-relevant-than-I-expected to the subject
line)

- Don Klipstein (don@misty.com)

Then tell me why you didn't reply in a more appropriate part of the
thread? I was answering some questions from another poster.


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

 

[Don Klipstein]

In article <4675077B.CFAAC673@earthlink.net>, Michael A. Terrell wrote:

Don Klipstein wrote:

In article <46747B68.69CF75EB@earthlink.net>, Michael A. Terrell wrote:

(Snipped because I found it less-relevant-than-I-expected to the subject
line)

- Don Klipstein (don@misty.com)

Then tell me why you didn't reply in a more appropriate part of the
thread? I was answering some questions from another poster.

That was where the thread started when I first saw it. Either my news
server went screwy for a while or I failed to notice the thread before.

I now see that there were earlier articles having to do with power
supplies that are constantly plugged in.

- Don Klipstein (don@misty.com)

 

[mm]

On Sun, 17 Jun 2007 14:46:43 +0000 (UTC), don@manx.misty.com (Don
Klipstein) wrote:

In article <4675077B.CFAAC673@earthlink.net>, Michael A. Terrell wrote:
Don Klipstein wrote:

In article <46747B68.69CF75EB@earthlink.net>, Michael A. Terrell wrote:

(Snipped because I found it less-relevant-than-I-expected to the subject
line)

- Don Klipstein (don@misty.com)

Then tell me why you didn't reply in a more appropriate part of the
thread? I was answering some questions from another poster.

Part of the thread is in alt.home.repair AND sci.electonicts.repair.

Another part is only in ahr.

I think I brought in ser, and the answers about wall warts are in the
other part of the thread.

That was where the thread started when I first saw it. Either my news
server went screwy for a while or I failed to notice the thread before.

You read ser iirc. So it's not that your server is screwy or that you
failed to notice.

There is almost always a third possibility, even though often people
(I'm not referring to you) don't want to believe it (Either it's
amnesty or it's deportation)

I now see that there were earlier articles having to do with power
supplies that are constantly plugged in.

OH, I should have read this sentence first. OOPs. To find the posts
in ahr, you should come with the subject name and the date, because
there is so much traffic on Ahr that it will be hard to find
otehrwise. Or use groups.google and the exact subject name.

> - Don Klipstein (don@misty.com)

 

[Don Klipstein]

In article <o6bb735mlcinnscp3cujn8ll64dr34v7qa@4ax.com>, mm wrote:

On Sun, 17 Jun 2007 14:46:43 +0000 (UTC), don@manx.misty.com (Don
Klipstein) wrote:

In article <4675077B.CFAAC673@earthlink.net>, Michael A. Terrell wrote:
Don Klipstein wrote:

In article <46747B68.69CF75EB@earthlink.net>, Michael A. Terrell wrote:

(Snipped because I found it less-relevant-than-I-expected to the subject
line)

- Don Klipstein (don@misty.com)

Then tell me why you didn't reply in a more appropriate part of the
thread? I was answering some questions from another poster.

Part of the thread is in alt.home.repair AND sci.electonicts.repair.

Another part is only in ahr.

I think I brought in ser, and the answers about wall warts are in the
other part of the thread.

That was where the thread started when I first saw it. Either my news
server went screwy for a while or I failed to notice the thread before.

You read ser iirc. So it's not that your server is screwy or that you
failed to notice.

There is almost always a third possibility, even though often people
(I'm not referring to you) don't want to believe it (Either it's
amnesty or it's deportation)

I now see that there were earlier articles having to do with power
supplies that are constantly plugged in.

OH, I should have read this sentence first. OOPs. To find the posts
in ahr, you should come with the subject name and the date, because
there is so much traffic on Ahr that it will be hard to find
otehrwise. Or use groups.google and the exact subject name.

I was reading ahr. I could have glanced too quickly through a range of
subject lines towards the end of the alphabet. I scan through subject
lines more carefully in the range starting with "C", "F" and "L" since I
pay more attention to lighting and fluorescent lamps than to most other
stuff that comes up in ahr.

- Don Klipstein (don@misty.com)

 

[Meat Plow]

On Wed, 20 Jun 2007 20:25:39 +0000, noone wrote:

I have a couple of ~15 yr old fluoresent shop lights which have quit
functioning. They are the "instant start" type, yet don't use a canned
starter. I took them apart and traced out the wiring and found that they
just use a couple of chokes and a couple of R/C's to light up two F40CW's.
If I correctly traced the wiring, it looks like this diagram I scratched on
the back of a piece of junk mail:

http://usera.imagecave.com/Davetech/fluoresentdiag.jpg

The chokes look okay, the 150K resistors are fine, but the cheap paper/foil
capacitors have been hot (scorched sides!), swollen, and one had a crack
where the smoke apparently got out. My problem is there are no markings on
the caps. Anyone venture a guess at what the value would be? Is the value
critical?

I know, replacing the fixture would be inexpensive and intelligent, but I'm
retired, on a very tight income, don't have a ready ride to the dept store,
and hate to add to the landfill stuff that could be fixed. Besides, I'm a
tinkerer at heart.

Thanks for any help,

redirected to sci.electronics.repair for some of the best answers and
longest threads you'll ever get (regardless if they're right or wrong)

 

[pfjw@aol.com]

On Jun 20, 10:50 pm, Meat Plow <m...@meatplow.local> wrote:

On Wed, 20 Jun 2007 20:25:39 +0000, noone wrote:
I have a couple of ~15 yr old fluoresent shop lights which have quit
functioning. They are the "instant start" type, yet don't use a canned
starter. I took them apart and traced out the wiring and found that they
just use a couple of chokes and a couple of R/C's to light up two F40CW's.
If I correctly traced the wiring, it looks like this diagram I scratched on
the back of a piece of junk mail:

http://usera.imagecave.com/Davetech/fluoresentdiag.jpg

The chokes look okay, the 150K resistors are fine, but the cheap paper/foil
capacitors have been hot (scorched sides!), swollen, and one had a crack
where the smoke apparently got out. My problem is there are no markings on
the caps. Anyone venture a guess at what the value would be? Is the value
critical?

I know, replacing the fixture would be inexpensive and intelligent, but I'm
retired, on a very tight income, don't have a ready ride to the dept store,
and hate to add to the landfill stuff that could be fixed. Besides, I'm a
tinkerer at heart.

Thanks for any help,

redirected to sci.electronics.repair for some of the best answers and
longest threads you'll ever get (regardless if they're right or wrong)- Hide quoted text -

- Show quoted text -

Some information here on cap values.

http://www.affordablelighting.com/faq-fluorescent_lamps.php#fb1

BUT, and here is the biggest BUT.... at least one of those beasts in
there is not a choke, but a "primary autotranformer" to make the
different voltages required.

As to replacing the fixture/ballast vs. a couple of caps.

Home Depot/Dollar Store/Lowes will sell you a "shop-light" complete
with tubes for about $12. You will spend several $$ for the caps, they
will need to be AC rated at 200V or better, and you will need either
to order them on-line and pay shipping or find an electrical supply-
house and pay 'retail'. I betcha that purchasing a new ballast
outright (and save the sheet-metal, sockets and lamps) will be your
cheapest option,

Capacity does matter.

Be careful. you could be seeing the most expensive savings ever. And
if you do decide to repair the unit without proper testing of the
choke and transformer, you will wind up still having to replace the
fixture at the end, notwithstanding the possibly spectacular method
whereby the unit tells you to try something else.

Peter Wieck
Wyncote, PA

 

On 21 Jun, 14:51, "p...@aol.com" <p...@aol.com> wrote:

On Jun 20, 10:50 pm, Meat Plow <m...@meatplow.local> wrote:
On Wed, 20 Jun 2007 20:25:39 +0000, noone wrote:

I have a couple of ~15 yr old fluoresent shop lights which have quit
functioning. They are the "instant start" type, yet don't use a canned
starter. I took them apart and traced out the wiring and found that they
just use a couple of chokes and a couple of R/C's to light up two F40CW's.
If I correctly traced the wiring, it looks like this diagram I scratched on
the back of a piece of junk mail:

http://usera.imagecave.com/Davetech/fluoresentdiag.jpg

These are resonant circuits on both sides, and cap value is critical.

As for how to determine the value, either measure a working one, find
a similar type of ballast and see what value it uses, or maybe ask at
the expert sites such as sci.engr.lighting, or ask folk like Don etc
at their expert sites.

I know, replacing the fixture would be inexpensive and intelligent, but I'm
retired, on a very tight income, don't have a ready ride to the dept store,
and hate to add to the landfill stuff that could be fixed. Besides, I'm a
tinkerer at heart.

Thanks for any help,

As to replacing the fixture/ballast vs. a couple of caps.

Home Depot/Dollar Store/Lowes will sell you a "shop-light" complete
with tubes for about $12. You will spend several $$ for the caps, they
will need to be AC rated at 200V or better, and you will need either
to order them on-line and pay shipping or find an electrical supply-
house and pay 'retail'. I betcha that purchasing a new ballast
outright (and save the sheet-metal, sockets and lamps) will be your
cheapest option,

Capacity does matter.

Be careful. you could be seeing the most expensive savings ever. And
if you do decide to repair the unit without proper testing of the
choke and transformer, you will wind up still having to replace the
fixture at the end, notwithstanding the possibly spectacular method
whereby the unit tells you to try something else.

Peter Wieck
Wyncote, PA

Tinkerers usually use salvaged parts that cost nothing.

As for the claim that reliability of old fittings is bad, the opposite
is in fact the case, with old fl fittings enjoying greater average
life expectancy than new.

What isnt worth salvaging is old halophosphate T12 tubes. Theyre free,
but new lower powered T8s will pay their cost back in use plus a bit
more.


NT

 

[pfjw@aol.com]

On Jun 21, 10:24 am, meow2...@care2.com wrote:

What isnt worth salvaging is old halophosphate T12 tubes. Theyre free,
but new lower powered T8s will pay their cost back in use plus a bit

T8 lamps will require a different ballast... Not a bad idea ultimately
if the first-cost for new lamps and ballasts can be carried. Of
course, for ~$17, Home Depot will sell you a new 2-tube T8 shop-light,
complete. Our local one had a stack of them out front @ $16.99 + tax.

Peter Wieck
Wyncote, PA

 

[Franc Zabkar]

On Wed, 20 Jun 2007 22:50:51 -0400, Meat Plow <meat@meatplow.local>
put finger to keyboard and composed:

On Wed, 20 Jun 2007 20:25:39 +0000, noone wrote:

I have a couple of ~15 yr old fluoresent shop lights which have quit
functioning. They are the "instant start" type, yet don't use a canned
starter. I took them apart and traced out the wiring and found that they
just use a couple of chokes and a couple of R/C's to light up two F40CW's.
If I correctly traced the wiring, it looks like this diagram I scratched on
the back of a piece of junk mail:

http://usera.imagecave.com/Davetech/fluoresentdiag.jpg

That doesn't look right. For one thing, there doesn't seem to be
anything to limit the lamp current.

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.

 

[pfjw@aol.com]

On Jun 21, 4:43 pm, Franc Zabkar <fzab...@iinternode.on.net> wrote:

On Wed, 20 Jun 2007 22:50:51 -0400, Meat Plow <m...@meatplow.local
put finger to keyboard and composed:

On Wed, 20 Jun 2007 20:25:39 +0000, noone wrote:

I have a couple of ~15 yr old fluoresent shop lights which have quit
functioning. They are the "instant start" type, yet don't use a canned
starter. I took them apart and traced out the wiring and found that they
just use a couple of chokes and a couple of R/C's to light up two F40CW's.
If I correctly traced the wiring, it looks like this diagram I scratched on
the back of a piece of junk mail:

http://usera.imagecave.com/Davetech/fluoresentdiag.jpg

That doesn't look right. For one thing, there doesn't seem to be
anything to limit the lamp current.

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.

One of the "chokes" is an auto-transformer.

Peter Wieck
Wyncote, PA

 

[Arfa Daily]

<pfjw@aol.com> wrote in message
news:1182437721.136666.88560@o61g2000hsh.googlegroups.com...

On Jun 21, 10:24 am, meow2...@care2.com wrote:

What isnt worth salvaging is old halophosphate T12 tubes. Theyre free,
but new lower powered T8s will pay their cost back in use plus a bit

T8 lamps will require a different ballast... Not a bad idea ultimately
if the first-cost for new lamps and ballasts can be carried. Of
course, for ~$17, Home Depot will sell you a new 2-tube T8 shop-light,
complete. Our local one had a stack of them out front @ $16.99 + tax.

Peter Wieck
Wyncote, PA

Over here in the UK, T8's and T12's are sold interchangeably as merely
"standard" or "slimline" - no different ballast or fitting required. I have
many 15 or more year-old fixtures here, that came with T12 tubes originally,
that now have T8's in them.

Arfa

 

[pfjw@aol.com]

On Jun 22, 4:00 am, "Arfa Daily" <arfa.da...@ntlworld.com> wrote:

Over here in the UK, T8's and T12's are sold interchangeably as merely
"standard" or "slimline" - no different ballast or fitting required. I have
many 15 or more year-old fixtures here, that came with T12 tubes originally,
that now have T8's in them.

Just don't go the other way - and - if you are still using magnetic
ballasts, you are not realizing any savings... OK, the difference
between a nominal 40W (really about 38), and a nominal 34W (really
about 32), with the ballast taking nearly 30W in its own right. vs.
less than 10W for the typical electronic ballast and 5W for a high
efficiency ballast.

And, if you are running a T8 on a T12 ballast the T8 will run dimmer.
But, I would have thought you would be running mostly T5 by now?

Peter Wieck
Wyncote, PA

 

On 22 Jun, 11:41, "p...@aol.com" <p...@aol.com> wrote:

On Jun 22, 4:00 am, "Arfa Daily" <arfa.da...@ntlworld.com> wrote:

Over here in the UK, T8's and T12's are sold interchangeably as merely
"standard" or "slimline" - no different ballast or fitting required. I have
many 15 or more year-old fixtures here, that came with T12 tubes originally,
that now have T8's in them.

Just don't go the other way - and - if you are still using magnetic
ballasts, you are not realizing any savings... OK, the difference
between a nominal 40W (really about 38), and a nominal 34W (really
about 32), with the ballast taking nearly 30W in its own right. vs.
less than 10W for the typical electronic ballast and 5W for a high
efficiency ballast.

And, if you are running a T8 on a T12 ballast the T8 will run dimmer.
But, I would have thought you would be running mostly T5 by now?

Peter Wieck
Wyncote, PA

This sort of thing often happens in these discussions. UK and US
standards are different, we dont even have the same type of 4' tubes
you have.

Here (UK) there are 2 types of 4' tube:
T12 40w
T8 36w
Both are designed to run on the same ballast, IOW the T8s are retrofit
tubes rather than requiring a new standard of ballast.

Thus there are 2 ways to save a very little energy:
1. replace T12 with T8
2. Replace mag ballast fitting with electronic.


NT

 

[James Sweet]

Over here in the UK, T8's and T12's are sold interchangeably as merely
"standard" or "slimline" - no different ballast or fitting required. I
have many 15 or more year-old fixtures here, that came with T12 tubes
originally, that now have T8's in them.

Arfa

The UK T8 lamps are different than the US lamps. My friend and I have
discussed this quite a bit and came to the conclusion that the true 40W T12
lamps over here in the US are the same as in the UK, though the old standard
phosphor types are all limited to 34W now which never happened there because
the lower lamp voltage when used with a choke just increases the current to
compensate and no power is saved.

US T8 lamps are 32W for the 4' size. The ballasts they use are all high
frequency electronic, if you put one in a standard rapid start T12 fixture
they will light up, but not very bright and lamp life will be decreased.

 

[James Sweet]

This sort of thing often happens in these discussions. UK and US
standards are different, we dont even have the same type of 4' tubes
you have.

Here (UK) there are 2 types of 4' tube:
T12 40w
T8 36w
Both are designed to run on the same ballast, IOW the T8s are retrofit
tubes rather than requiring a new standard of ballast.

Thus there are 2 ways to save a very little energy:
1. replace T12 with T8
2. Replace mag ballast fitting with electronic.

The savings you can get with an electronic ballast are significantly less
than what we see when replacing an autotransformer ballast. A standard 4'
twin tube rapid start ballast burns up something like 18W just in the
ballast itself. A choke ballast for 240V mains and the same tubes burns half
that or less.

 

[N Cook]

Tam/WB2TT <t-tammaru@c0mca$t.net> wrote in message
news:y8ednYX4_vtoOB_bnZ2dnUVZ_qOpnZ2d@comcast.com...

"N Cook" <diverse8@gazeta.pl> wrote in message
news:f5u30d$c0e$1@inews.gazeta.pl...
This is someone's graphic of internal wiring of a UK line connector
http://web.onetel.net.uk/~uncletony/images/mains-plug.jpg
note the screw down, into captive hollows, for the bared leads , also
the
cord grip and also the internal fuse.
This week I had to wire up a USA mains connector like this one
http://www.maplin.co.uk/images/Full/hl19v.jpg
I could not find an internal pic or graphic but it reminded me of the
internal wiring of UK plugs of 50 years ago, before ROSPA and BS got
involved - , wrap around screw terminals that can easily shed a loose
wire
filament,

I have never seen a house here in the US wired with stranded wire, except
for one built in 1906. Generally #14 solid copper. BTW the 3 wire UK plug
reminds me of what is used on a clothes dryer or stove here. Would you
actually use one of these on a lamp?

Tam

both of them, live and neutral surprisingly close together and
what I find very odd , no cord grip/anchor and no fuse.

We have no choice in the matter, by law, we can use 1,2 or 3 amp fuses
inside these plugs but thats the only choice

The USA cannot have the equivalent of RoSPA (Royal Society for the
Prevention of Accidents), AFAICS none of the USA ones have child preventers
on them unless the mouldings on the wall outlets preclude that eventuality
of small fiongers touching both pins.
The other notable difference is the insulated pins that have been necessary
refinement, again by law, for 20 years or so
You can just see the orange plastic bits extending up the brass pins on the
first pic on this wiki and the black bits on the one lower down on
http://en.wikipedia.org/wiki/BS_1363
....
The phase and neutral pins on modern plugs have insulated bases to prevent
finger contact with pins and also to stop metal sheets (for example, fallen
blind slats) from becoming live if lodged between the wall and a partly
pulled out plug. A downside to this prong insulation is that it may
contribute to damaged sockets not making good contact with the prongs, which
may even melt the latter. No such problems exist with healthy sockets.
....

as an aside someone told me that per million houses there are more house
fires in the USA due to wiring faults than any other country, partly due to
a lot of timber construction and partly due to the higher current for a
given KW of power transfered - is that the case?