Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems.

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Default Power Inverters

We're looking for a power inverter to recharge our Compaq notebook
in the car. Is it better to buy one with a larger rating (400W) rather than
a smaller one? Black & Decker has a 100W model ($13) and it gets
decent reviews:

http://tinyurl.com/5fstl9

But the notebook uses ~90W, so we'll be very close to this inverter's
capacity. The alternative is something larger, e.g.

http://tinyurl.com/6nfbrp

This one's 400W, but we're wondering if the extra cost is worth it.

Thanks for any advice/opinions/info.


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lid wrote:
We're looking for a power inverter to recharge our Compaq notebook
in the car. Is it better to buy one with a larger rating (400W) rather than
a smaller one? Black & Decker has a 100W model ($13) and it gets
decent reviews:

http://tinyurl.com/5fstl9

But the notebook uses ~90W, so we'll be very close to this inverter's
capacity. The alternative is something larger, e.g.

http://tinyurl.com/6nfbrp

This one's 400W, but we're wondering if the extra cost is worth it.

Thanks for any advice/opinions/info.


As a thought - what is the DC requirements of the Laptop ? - it might
not be necessary to go up to mains voltage and then back down.

If it is - what other use might you want from the inverter ?

The 90W the notebook needs, is this its DC loading on its own charger or
the chargers loading on the mains ?
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"f825_677" wrote in message ...
lid wrote:
We're looking for a power inverter to recharge our Compaq notebook
in the car. Is it better to buy one with a larger rating (400W) rather than
a smaller one? Black & Decker has a 100W model ($13) and it gets
decent reviews:

http://tinyurl.com/5fstl9

But the notebook uses ~90W, so we'll be very close to this inverter's
capacity. The alternative is something larger, e.g.

http://tinyurl.com/6nfbrp

This one's 400W, but we're wondering if the extra cost is worth it.

Thanks for any advice/opinions/info.


As a thought - what is the DC requirements of the Laptop ? - it might
not be necessary to go up to mains voltage and then back down.


The notebook's AC adapter has these specs:

Input: 100-240V
Output: 18.5V 3.5A

Which, now that I've actually looked, is ~65W not 90W.

If it is - what other use might you want from the inverter ?


None.

The 90W the notebook needs, is this its DC loading on its own charger or
the chargers loading on the mains ?


65W is the DC loading on its own charger.


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On Thu, 20 Nov 2008 09:39:59 -0800, wrote:

We're looking for a power inverter to recharge our Compaq notebook
in the car. Is it better to buy one with a larger rating (400W) rather than
a smaller one? Black & Decker has a 100W model ($13) and it gets
decent reviews:

http://tinyurl.com/5fstl9

But the notebook uses ~90W, so we'll be very close to this inverter's
capacity. The alternative is something larger, e.g.

http://tinyurl.com/6nfbrp

This one's 400W, but we're wondering if the extra cost is worth it.

Thanks for any advice/opinions/info.


The most efficient option is to get a DC-DC converterthat changes 12
volts from the car to the 19 volts the laptop needs.

These are available for under $60US.

John
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f825_677 wrote:

lid wrote:
We're looking for a power inverter to recharge our Compaq notebook
in the car. Is it better to buy one with a larger rating (400W) rather than
a smaller one? Black & Decker has a 100W model ($13) and it gets
decent reviews:

http://tinyurl.com/5fstl9

But the notebook uses ~90W, so we'll be very close to this inverter's
capacity. The alternative is something larger, e.g.

http://tinyurl.com/6nfbrp

This one's 400W, but we're wondering if the extra cost is worth it.

Thanks for any advice/opinions/info.


As a thought - what is the DC requirements of the Laptop ? - it might
not be necessary to go up to mains voltage and then back down.



Not a good idea. There can be spikes of up to 400 volts in an
automotive electrical system. Then there is the possibility of a 'load
dump' which happens when the voltage regulator fails, or a loose battery
cable.


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In article ,
Michael A. Terrell wrote:
As a thought - what is the DC requirements of the Laptop ? - it might
not be necessary to go up to mains voltage and then back down.



Not a good idea. There can be spikes of up to 400 volts in an
automotive electrical system. Then there is the possibility of a 'load
dump' which happens when the voltage regulator fails, or a loose battery
cable.


Makes you wonder just how all the various computers in the modern car
survive...

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Dave Plowman (News) wrote:
In article ,
Michael A. Terrell wrote:
As a thought - what is the DC requirements of the Laptop ? - it might
not be necessary to go up to mains voltage and then back down.



Not a good idea. There can be spikes of up to 400 volts in an
automotive electrical system. Then there is the possibility of a 'load
dump' which happens when the voltage regulator fails, or a loose battery
cable.


Makes you wonder just how all the various computers in the modern car
survive...

Fat wires directly to the battery has always served me
well in a number of instrumented cars.
Only one accident with a blown regulator in a generator,
suddenly about 100 volt instead of 12 volt.
That was over a period of 40 years.
The battery works like a rather big capacitor.
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In article ,
Sjouke Burry wrote:
Dave Plowman (News) wrote:
In article ,
Michael A. Terrell wrote:
As a thought - what is the DC requirements of the Laptop ? - it might
not be necessary to go up to mains voltage and then back down.



Not a good idea. There can be spikes of up to 400 volts in an
automotive electrical system. Then there is the possibility of a
'load dump' which happens when the voltage regulator fails, or a
loose battery cable.


Makes you wonder just how all the various computers in the modern car
survive...

Fat wires directly to the battery has always served me
well in a number of instrumented cars.
Only one accident with a blown regulator in a generator,
suddenly about 100 volt instead of 12 volt.
That was over a period of 40 years.
The battery works like a rather big capacitor.


To get 100 volts you'd need not only a faulty regulator but a faulty or
disconnected battery. Turning the average alternator hard on only usually
results in the high teens volts wise. Although I've no idea what happens
with some of these modern ultra high powered water cooled types. ;-)

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In message , Claude
Hopper writes
Cheap inverters put out a modified sign wave that looks more like a
stepped pyramid than a sing wave. Not good for electronics and
transformers.

Cheap UPS devices designed to run servers and PCs only put out a
modified sine wave, they seem to cope fine.

About the only symptom I've ever seen from using devices on inverters
in my cars is that they generate a little more noise than they normally
would when under load. Other than that, nothing. All of my laptops have
been run in the car on inverters but I'd have to agree with another
poster, the most efficient way to do this is with a DC to DC converter.
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Clint Sharp wrote:

In message , Claude
Hopper writes

Cheap inverters put out a modified sign wave that looks more like a
stepped pyramid than a sing wave. Not good for electronics and
transformers.

Cheap UPS devices designed to run servers and PCs only put out a
modified sine wave, they seem to cope fine.

About the only symptom I've ever seen from using devices on inverters
in my cars is that they generate a little more noise than they normally
would when under load. Other than that, nothing. All of my laptops have
been run in the car on inverters but I'd have to agree with another
poster, the most efficient way to do this is with a DC to DC converter.


If the equipment the inverter is running contains a typical switched
mode power supply with a bridge rectifier or voltage doubler input
circuit, it is almost certainly under less stress running from a
so-called modified sine source than it is from the power line. The peak
voltage is designed to be the same, but as the waveform is basically
flat topped, the peak input current is reduced and the input diodes and
resevoir caps will run a little cooler!


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Dave Plowman (News) wrote:
In article ,
Sjouke Burry wrote:
Dave Plowman (News) wrote:
In article ,
Michael A. Terrell wrote:
As a thought - what is the DC requirements of the Laptop ? - it might
not be necessary to go up to mains voltage and then back down.

Not a good idea. There can be spikes of up to 400 volts in an
automotive electrical system. Then there is the possibility of a
'load dump' which happens when the voltage regulator fails, or a
loose battery cable.
Makes you wonder just how all the various computers in the modern car
survive...

Fat wires directly to the battery has always served me
well in a number of instrumented cars.
Only one accident with a blown regulator in a generator,
suddenly about 100 volt instead of 12 volt.
That was over a period of 40 years.
The battery works like a rather big capacitor.


To get 100 volts you'd need not only a faulty regulator but a faulty or
disconnected battery. Turning the average alternator hard on only usually
results in the high teens volts wise. Although I've no idea what happens
with some of these modern ultra high powered water cooled types. ;-)

At those heavy overloads the battery will form a gas layer
between electrolyte and electrode.
That gas layer will act as high resistance(for a short time),
long enough to explode the caps in a number of convertors.
After servicing about 12 supplies and an assorted 10 opamps,
we were back in bizness.
The generator survived.
The battery as well.
The regulator needed two transistors and a new zener diode.
But spikes as mentioned? Never a problem.
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Clint Sharp wrote:
In message , Claude
Hopper writes
Cheap inverters put out a modified sign wave that looks more like a
stepped pyramid than a sing wave. Not good for electronics and
transformers.

Cheap UPS devices designed to run servers and PCs only put out a
modified sine wave, they seem to cope fine.

About the only symptom I've ever seen from using devices on inverters
in my cars is that they generate a little more noise than they normally
would when under load. Other than that, nothing. All of my laptops have
been run in the car on inverters but I'd have to agree with another
poster, the most efficient way to do this is with a DC to DC converter.


Certainly more efficient; but I change laptops too often to buy a
dedicated 12v supply every time. The 110 inverter works for me; but I
'have' seen universal models. My Dell laptop is sensitive to power
supplies, though. The cheap Targus unit that came with it will run the
computer, but won't charge the battery (one of the reasons I got it so
cheap).

jak
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"Dave Plowman (News)" wrote:

In article ,
Michael A. Terrell wrote:
As a thought - what is the DC requirements of the Laptop ? - it might
not be necessary to go up to mains voltage and then back down.


Not a good idea. There can be spikes of up to 400 volts in an
automotive electrical system. Then there is the possibility of a 'load
dump' which happens when the voltage regulator fails, or a loose battery
cable.


Makes you wonder just how all the various computers in the modern car
survive...



No wondering, at all. They are designed to meet the specifications.
Believe whatever you want, but there are detailed specifications for
automotive electronics, and the required protection. G0 to the design
newsgroup and tell some of the engineers that there are no spikes, or
load dumps.

The early Delco transistor car radios had a 'Spark plate', that arced
over to damp the spikes, along with a large series inductor.

ignorance may be bliss, but it damages lots of equipment.


--
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prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida
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In article ,
Michael A. Terrell wrote:
Makes you wonder just how all the various computers in the modern car
survive...



No wondering, at all. They are designed to meet the specifications.
Believe whatever you want, but there are detailed specifications for
automotive electronics, and the required protection. G0 to the design
newsgroup and tell some of the engineers that there are no spikes, or
load dumps.


The early Delco transistor car radios had a 'Spark plate', that arced
over to damp the spikes, along with a large series inductor.


I'd guess the Delco designers knew how crap their car electrics were.
Early Blaupunkt seemed to work just fine without.

ignorance may be bliss, but it damages lots of equipment.


Sure it might if you're stupid enough to disconnect the battery with the
engine running.

It's a bit like memory effect on Ni-Cads - it can happen but is very very
rare. Doesn't stop some 'engineers' saying it happens all the time. And
others believing them.

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Dave Plowman London SW
To e-mail, change noise into sound.
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"Dave Plowman (News)" wrote:

In article ,
Michael A. Terrell wrote:
Makes you wonder just how all the various computers in the modern car
survive...


No wondering, at all. They are designed to meet the specifications.
Believe whatever you want, but there are detailed specifications for
automotive electronics, and the required protection. G0 to the design
newsgroup and tell some of the engineers that there are no spikes, or
load dumps.


The early Delco transistor car radios had a 'Spark plate', that arced
over to damp the spikes, along with a large series inductor.


I'd guess the Delco designers knew how crap their car electrics were.
Early Blaupunkt seemed to work just fine without.



Every crappy solid state Blaupunkt I worked on had similar
protection. They were the lowest grade construction of any automotive
electronics that I ever had the misfortune to repair. I repaired over
1000 car radios when I was a teenager. Delco was one of the best, as
far as durability & ease of repair. They were durable, because they were
better designed. Philco was the worst US design, followed by the
Japanese radios, then the European designs. I never saw anything from
Russia, but I've heard that they were even worse.


ignorance may be bliss, but it damages lots of equipment.


Sure it might if you're stupid enough to disconnect the battery with the
engine running.



So, you claim that batteries never fail, or battery lugs come loose?
You've never seen an open fusible link? You are just a parts changer
who doesn't understand the intimate details of a design.

http://www.google.com/search?hl=en&rls=com.microsoft%3Aen-us%3AIE-SearchBox&rlz=1I7GGLD&q=automotive+electrical+load +dump
Results 1 - 10 of about 177,000 for automotive electrical load dump.
(0.30 seconds)


It's a bit like memory effect on Ni-Cads - it can happen but is very very
rare. Doesn't stop some 'engineers' saying it happens all the time. And
others believing them.



Its nothing like Ni-Cad 'Memory effect' which was reported in some
spacecraft that had the exact same charging cycle, over and over due to
their constant orbit. The effect was proven in the lab by duplicating
the charging cycles. By varying the charge cycles that doesn't occur.


--
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The crazy, and the insane.
The first sign of insanity is denying that you're crazy.


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Clint Sharp wrote:

In message , Claude
Hopper writes
Cheap inverters put out a modified sign wave that looks more like a
stepped pyramid than a sing wave. Not good for electronics and
transformers.

Cheap UPS devices designed to run servers and PCs only put out a
modified sine wave, they seem to cope fine.

About the only symptom I've ever seen from using devices on inverters
in my cars is that they generate a little more noise than they normally
would when under load. Other than that, nothing. All of my laptops have
been run in the car on inverters but I'd have to agree with another
poster, the most efficient way to do this is with a DC to DC converter.



The DC to DC converter is nothing more than the inverter & switching
power supply in the same case. The incoming DC is chopped, stepped up,
and regulated to the required voltage.


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listed, or I will not see your messages.

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your account: http://www.usenettools.net/ISP.htm


There are two kinds of people on this earth:
The crazy, and the insane.
The first sign of insanity is denying that you're crazy.
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In message , jakdedert
writes
Certainly more efficient; but I change laptops too often to buy a
dedicated 12v supply every time.

There are universal 12v adapters just as there are universal AC
adapters.

The 110 inverter works for me; but I 'have' seen universal models. My
Dell laptop is sensitive to power supplies, though.

Some of the Dell laptops can positively identify a genuine Dell PSU and
won't charge if it isn't genuine. Dell put a silicon serial number IC
inside the PSU which the laptop can read.

The cheap Targus unit that came with it will run the computer, but
won't charge the battery (one of the reasons I got it so cheap).

It's fairly simple to add the serial number if you can find a defunct
PSU (although a major reason for Dell adapters being faulty is that the
serial number chip dies!) but genuine AC adaptors are pretty cheap on
eBay.


jak


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In message , Michael A.
Terrell writes
All of my laptops have
been run in the car on inverters but I'd have to agree with another
poster, the most efficient way to do this is with a DC to DC converter.



The DC to DC converter is nothing more than the inverter & switching
power supply in the same case. The incoming DC is chopped, stepped up,
and regulated to the required voltage.

It's just a boost converter, there's no separate 'step up' stage
followed by a regulator. Can be done with a single IC but most of the
ones I've seen have been based on the MC34063 controlling a high current
MOSFET switch driving a toroid.


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"Michael A. Terrell" wrote in message m...

Clint Sharp wrote:

In message , Claude
Hopper writes
Cheap inverters put out a modified sign wave that looks more like a
stepped pyramid than a sing wave. Not good for electronics and
transformers.

Cheap UPS devices designed to run servers and PCs only put out a
modified sine wave, they seem to cope fine.

About the only symptom I've ever seen from using devices on inverters
in my cars is that they generate a little more noise than they normally
would when under load. Other than that, nothing. All of my laptops have
been run in the car on inverters but I'd have to agree with another
poster, the most efficient way to do this is with a DC to DC converter.



The DC to DC converter is nothing more than the inverter & switching
power supply in the same case. The incoming DC is chopped, stepped up,
and regulated to the required voltage.


Thanks all for the info and advice.

Any recs for a specific make/model# would be greatly appreciated.


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In article ,
Michael A. Terrell wrote:
I'd guess the Delco designers knew how crap their car electrics were.
Early Blaupunkt seemed to work just fine without.



Every crappy solid state Blaupunkt I worked on had similar
protection.


Not on the ones I've owned.

They were the lowest grade construction of any automotive
electronics that I ever had the misfortune to repair.


You're talking ****e.

I repaired over
1000 car radios when I was a teenager. Delco was one of the best, as
far as durability & ease of repair.


Can't be that good if you had to repair over 1000.

They were durable, because they were
better designed. Philco was the worst US design, followed by the
Japanese radios, then the European designs. I never saw anything from
Russia, but I've heard that they were even worse.



ignorance may be bliss, but it damages lots of equipment.


Sure it might if you're stupid enough to disconnect the battery with
the engine running.



So, you claim that batteries never fail, or battery lugs come loose?


It's not common, no. And the usual first symptom is the car won't start.

You've never seen an open fusible link? You are just a parts changer
who doesn't understand the intimate details of a design.


Heh heh. That from the one who thinks early Blaupunkt was badly made...

http://www.google.com/search?hl=en&rls=com.microsoft%3Aen-us%3AIE-SearchBox&rlz=1I7GGLD&q=automotive+electrical+load +dump

Results 1 - 10 of about 177,000 for automotive electrical load dump.
(0.30 seconds)


You seem very hung up about it. Is it the latest fad?


It's a bit like memory effect on Ni-Cads - it can happen but is very
very rare. Doesn't stop some 'engineers' saying it happens all the
time. And others believing them.



Its nothing like Ni-Cad 'Memory effect' which was reported in some
spacecraft that had the exact same charging cycle, over and over due to
their constant orbit. The effect was proven in the lab by duplicating
the charging cycles. By varying the charge cycles that doesn't occur.


Indeed. But plenty thought it could happened to their mobile phones, etc.

--
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Dave Plowman London SW
To e-mail, change noise into sound.


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"Dave Plowman (News)" wrote:

In article ,
Michael A. Terrell wrote:
I'd guess the Delco designers knew how crap their car electrics were.
Early Blaupunkt seemed to work just fine without.


Every crappy solid state Blaupunkt I worked on had similar
protection.


Not on the ones I've owned.

They were the lowest grade construction of any automotive
electronics that I ever had the misfortune to repair.


You're talking ****e.

I repaired over
1000 car radios when I was a teenager. Delco was one of the best, as
far as durability & ease of repair.


Can't be that good if you had to repair over 1000.



I did it for a living, in a large city. That 1000+ radios was all
brands. The Delcos usually took less time to repair than it took to
write the service ticket. The Philco, Motorola & Bendix took a half
hour to one and a half hours, while the Blaupunkt repairs averaged nine
months, because they were so damn slow to ship parts to their US
distributor. No part we needed was EVER in stock.


They were durable, because they were
better designed. Philco was the worst US design, followed by the
Japanese radios, then the European designs. I never saw anything from
Russia, but I've heard that they were even worse.


ignorance may be bliss, but it damages lots of equipment.

Sure it might if you're stupid enough to disconnect the battery with
the engine running.


So, you claim that batteries never fail, or battery lugs come loose?


It's not common, no. And the usual first symptom is the car won't start.



Are you really that ignorant? A lot of failures occur while on the
road. A worn battery cable can arc to the frame, cusing a large splie.
The fusible link can open, a battery cable can come off. It has all
happened, more than once. I can see you aren't smart enough to
uderstand the ramiofications, so this will be my last reply to your
ignoerant comments.


You've never seen an open fusible link? You are just a parts changer
who doesn't understand the intimate details of a design.


Heh heh. That from the one who thinks early Blaupunkt was badly made...



They were crap. At least whatever they exported to the US was. We
were the only shop for 100 miles who would even repair them in the
'70s. The parts were crammed in tightly, the wiring harnesses were
brittle, and broke quite easily. I still have some manuals, showing what
crap they were. Some had clusters of cheap Japanese style resistors
standing on end, that vibrated & cracked the leads. Just trying to
locate the bad one would break several that were already weak from metal
fatigue.



http://www.google.com/search?hl=en&rls=com.microsoft%3Aen-us%3AIE-SearchBox&rlz=1I7GGLD&q=automotive+electrical+load +dump

Results 1 - 10 of about 177,000 for automotive electrical load dump.
(0.30 seconds)


You seem very hung up about it. Is it the latest fad?



Hung up? Fad? 177,000 hits isn't a fad, idiot. It has been well
known by electrical engineers who designin automotive electronics since
the early '60s. One of the first hits was from the IEEE, but I doubt
you have any idea who or what they are.

Go to news:sci.electronics.design and let some of the older engineers
tell you of the damaged equipment and explosions from load dumps in the
labs.



Its nothing like Ni-Cad 'Memory effect' which was reported in some
spacecraft that had the exact same charging cycle, over and over due to
their constant orbit. The effect was proven in the lab by duplicating
the charging cycles. By varying the charge cycles that doesn't occur.


Indeed. But plenty thought it could happened to their mobile phones, etc.



Plenty of idiots who failed science class and who believe in old
wives tales and don't understand the chemietry involved.

Have you ever done any real design work, or ar you just another
ignorant parts changer? My design work is in space. Some is aboard the
International Space Station, comprising one of the main audio, video &
data communications systems. Definitely a place where you have to be
damn sure that your designs will not take out the main DC power buss, or
be affected by transients.



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Clint Sharp wrote:
In message , jakdedert
writes
Certainly more efficient; but I change laptops too often to buy a
dedicated 12v supply every time.

There are universal 12v adapters just as there are universal AC adapters.

The 110 inverter works for me; but I 'have' seen universal models. My
Dell laptop is sensitive to power supplies, though.

Some of the Dell laptops can positively identify a genuine Dell PSU and
won't charge if it isn't genuine. Dell put a silicon serial number IC
inside the PSU which the laptop can read.

The cheap Targus unit that came with it will run the computer, but
won't charge the battery (one of the reasons I got it so cheap).

It's fairly simple to add the serial number if you can find a defunct
PSU (although a major reason for Dell adapters being faulty is that the
serial number chip dies!) but genuine AC adaptors are pretty cheap on eBay.


The reason this was such a great deal was that I already 'had' a genuine
supply for it. I once had a surplus of Dell bricks, but I've gone
through a few, since. I could use another 90 watt supply for my D400
docking bay. If you boot it with the original 70 watt unit, the laptop
knows. You get a message in POST that tells you it knows...and it won't
boot the docking bay.

jak
jak


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In article ,
Michael A. Terrell wrote:
Can't be that good if you had to repair over 1000.



I did it for a living, in a large city. That 1000+ radios was all
brands. The Delcos usually took less time to repair than it took to
write the service ticket. The Philco, Motorola & Bendix took a half
hour to one and a half hours, while the Blaupunkt repairs averaged nine
months, because they were so damn slow to ship parts to their US
distributor. No part we needed was EVER in stock.


Right. So your opinion of a design is clouded by spares availability?


They were durable, because they were
better designed. Philco was the worst US design, followed by the
Japanese radios, then the European designs. I never saw anything from
Russia, but I've heard that they were even worse.


ignorance may be bliss, but it damages lots of equipment.

Sure it might if you're stupid enough to disconnect the battery with
the engine running.


So, you claim that batteries never fail, or battery lugs come loose?


It's not common, no. And the usual first symptom is the car won't start.



Are you really that ignorant? A lot of failures occur while on the
road. A worn battery cable can arc to the frame, cusing a large splie.
The fusible link can open, a battery cable can come off. It has all
happened, more than once. I can see you aren't smart enough to
uderstand the ramiofications, so this will be my last reply to your
ignoerant comments.


Strange. I've owned - and had experience of - hundreds of cars. And never
had this happen. Despite the majority having Lucas electrics.


You've never seen an open fusible link? You are just a parts changer
who doesn't understand the intimate details of a design.


Heh heh. That from the one who thinks early Blaupunkt was badly made...



They were crap. At least whatever they exported to the US was. We
were the only shop for 100 miles who would even repair them in the
'70s. The parts were crammed in tightly, the wiring harnesses were
brittle, and broke quite easily. I still have some manuals, showing what
crap they were. Some had clusters of cheap Japanese style resistors
standing on end, that vibrated & cracked the leads. Just trying to
locate the bad one would break several that were already weak from metal
fatigue.


My first one was a Frankfurt bought in the '60s when it was one of the few
available with FM - as well as LW, MW and SW. The only thing that went
wrong with that in a long life was the on/off switch which was part of the
volume control. A new part was in stock. And it appeared to be very well
made. I've no experience of their OEM stuff - I've no doubt it was made
down to a price same as all other OEM radios. It was transferred from car
to car - for a long time. I didn't junk it after buying a cars with
reasonable factory fit stuff - and sold it on Ebay not that long ago for
more than it cost new.



http://www.google.com/search?hl=en&rls=com.microsoft%3Aen-us%3AIE-SearchBox&rlz=1I7GGLD&q=automotive+electrical+load +dump

Results 1 - 10 of about 177,000 for automotive electrical load dump.
(0.30 seconds)


You seem very hung up about it. Is it the latest fad?



Hung up? Fad? 177,000 hits isn't a fad, idiot.


You don't know much about search engines, do you?

It has been well
known by electrical engineers who designin automotive electronics since
the early '60s. One of the first hits was from the IEEE, but I doubt
you have any idea who or what they are.


Go to news:sci.electronics.design and let some of the older engineers
tell you of the damaged equipment and explosions from load dumps in the
labs.


In the labs. Says it all.



Its nothing like Ni-Cad 'Memory effect' which was reported in
some spacecraft that had the exact same charging cycle, over and
over due to their constant orbit. The effect was proven in the lab
by duplicating the charging cycles. By varying the charge cycles
that doesn't occur.


Indeed. But plenty thought it could happened to their mobile phones, etc.



Plenty of idiots who failed science class and who believe in old
wives tales and don't understand the chemietry involved.


My point exactly.

Have you ever done any real design work, or ar you just another
ignorant parts changer? My design work is in space. Some is aboard the
International Space Station, comprising one of the main audio, video &
data communications systems. Definitely a place where you have to be
damn sure that your designs will not take out the main DC power buss, or
be affected by transients.


Lucas called themselves Lucas Aerospace...

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Clint Sharp wrote:

In message , Michael A.
Terrell writes
All of my laptops have
been run in the car on inverters but I'd have to agree with another
poster, the most efficient way to do this is with a DC to DC converter.



The DC to DC converter is nothing more than the inverter & switching
power supply in the same case. The incoming DC is chopped, stepped up,
and regulated to the required voltage.

It's just a boost converter, there's no separate 'step up' stage
followed by a regulator. Can be done with a single IC but most of the
ones I've seen have been based on the MC34063 controlling a high current
MOSFET switch driving a toroid.



I've seen both types.


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Clint Sharp writes:

Some of the Dell laptops can positively identify a genuine Dell PSU and
won't charge if it isn't genuine. Dell put a silicon serial number IC
inside the PSU which the laptop can read.


I thought Dell had stopped this BS [along with nonsense such as
non-standard desktop power supply pinout], but in any case it's a reason
to avoid Dell....


The cheap Targus unit that came with it will run the computer, but
won't charge the battery (one of the reasons I got it so cheap).

It's fairly simple to add the serial number if you can find a defunct
PSU (although a major reason for Dell adapters being faulty is that the
serial number chip dies!) but genuine AC adaptors are pretty cheap on
eBay.


How do you do this?

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& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433
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