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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  #1   Report Post  
Caroline
 
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Default PSU Fan Direction

I replaced my computer's 90-watt Newton power supply with a 180-watt Fortron
power supply today. I have not added any other new components, so the total
power consumed should not have changed. The new power supply unit (PSU) fits
perfectly in every way except one: The air flow direction is reversed. The old
fan's intake was on the back of the computer case. The fan exhaust was into the
computer, across the heat sink and CPU, and out the back of the case. The old
way arguably caused the case to be under a slight pressure.

The new fan arguably puts the case under a slight vacuum.

The heat sink prongs are hot but not so hot I can't safely (no burns) leave a
finger on it.

Should I just observe for awhile, playing it by ear?

Or should I figure out a way to reverse the fan flow direction in the new power
supply?

All experience is welcome. I googled and am not finding anything definitive.

Aside: After a lot of research on physical fit and electrical fit, brand names,
and cost, I bought the new power supply from newegg.com. With shipping,
altogether it cost $26. Ordered Tuesday night late, arrived Friday afternoon.


  #2   Report Post  
Ricky Eck
 
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Default PSU Fan Direction

Well, I am tiring to visualize the flow. But am having a hard time doing
it. But let me give you one rule of thumb. The cooler a CPU can run, the
more efficient it will work. The same with the whole computer. The CPU
should have a fan on it. This will keep the CPU cooled down. Now, it kinda
sounds like the fan from the PSU also was the fan that cooled the CPU (on
the old unit). Now the fan is no longer cooling the CPU. So, go to Radio
Shack, or your local computer store, and get a CPU fan. It fits on the heat
sink, and 2-4 screws will screw into, between the heat sink vents. If you
are getting two fans running opposite of each other, (I.E.back forcing out,
and the front fan forcing out, creating a void inside the case), you will
need to reverse one of the two fans. You need to create a nice airflow
through the case (I.E. Front to rear, or Rear to Front.) If you only have
one fan, may I suggest another, to create a nice airflow...

Hope this helps.
Rick

"Caroline" wrote in message
k.net...
I replaced my computer's 90-watt Newton power supply with a 180-watt

Fortron
power supply today. I have not added any other new components, so the

total
power consumed should not have changed. The new power supply unit (PSU)

fits
perfectly in every way except one: The air flow direction is reversed. The

old
fan's intake was on the back of the computer case. The fan exhaust was

into the
computer, across the heat sink and CPU, and out the back of the case. The

old
way arguably caused the case to be under a slight pressure.

The new fan arguably puts the case under a slight vacuum.

The heat sink prongs are hot but not so hot I can't safely (no burns)

leave a
finger on it.

Should I just observe for awhile, playing it by ear?

Or should I figure out a way to reverse the fan flow direction in the new

power
supply?

All experience is welcome. I googled and am not finding anything

definitive.

Aside: After a lot of research on physical fit and electrical fit, brand

names,
and cost, I bought the new power supply from newegg.com. With shipping,
altogether it cost $26. Ordered Tuesday night late, arrived Friday

afternoon.




  #3   Report Post  
Caroline
 
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Thanks, Ricky and Vidar.

Per your suggestions to increase the air flow, right now I am investigating a
fan for the heat sink.

I experimented a little more yesterday with the old power supply. To the touch,
it didn't seem as though the old fan cooled the heat sink or CPU any better than
the new one. I guess it's entirely possible the new fan's air circulation flow
over the CPU and heat sink is greater than the old one's, since the new power
supply is double the rating of the old one (180 Watts vs. 90 Watts). So maybe I
shouldn't worry about the new air flow direction.

But I am thinking I might get a little better performance overall if I throw in
a heat sink fan, like you said, Ricky. Seems like a fair gamble for under $20.

Performance seems better. For example, it seems I can dump more tasks on the
computer at the same time. (This sometimes froze things up.) I am still getting
some spontaneous Internet disconnects but am now suspecting the phone lines and
weather variations in my area.

Plus, the new power supply is quieter in steady state operation.

"Ricky Eck" wrote
Well, I am tiring to visualize the flow. But am having a hard time doing
it. But let me give you one rule of thumb. The cooler a CPU can run, the
more efficient it will work. The same with the whole computer. The CPU
should have a fan on it. This will keep the CPU cooled down. Now, it kinda
sounds like the fan from the PSU also was the fan that cooled the CPU (on
the old unit). Now the fan is no longer cooling the CPU. So, go to Radio
Shack, or your local computer store, and get a CPU fan. It fits on the heat
sink, and 2-4 screws will screw into, between the heat sink vents. If you
are getting two fans running opposite of each other, (I.E.back forcing out,
and the front fan forcing out, creating a void inside the case), you will
need to reverse one of the two fans. You need to create a nice airflow
through the case (I.E. Front to rear, or Rear to Front.) If you only have
one fan, may I suggest another, to create a nice airflow...

Hope this helps.
Rick



  #4   Report Post  
Ricky Eck
 
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Performance seems better. For example, it seems I can dump more tasks on
the
computer at the same time. (This sometimes froze things up.) I am still

getting
some spontaneous Internet disconnects but am now suspecting the phone

lines and
weather variations in my area.

Plus, the new power supply is quieter in steady state operation.


Well, that "Could" increase performance. I would say that putting a power
supply two times the amount then you had was the true increase of
performance. However, the freezing up problem can be caused by MANY things.
From slow processor, lack of Memory, slow video, ect. Sure, the processor
heating up, could cause it to run slow. But to be honest with you, many of
the lock ups are caused by software problems. Defragging the computer
greatly reduces "Lock-Up's" Eliminating Temp Files will frees up space, and
reducing the amount of programs running in the background (i.e. Real Player,
Messenger programs, ect), will free up resources. Eliminate any programs
from the start menu that you don't use. Not to mention any programs that
isn't in the start menu, that still start upon boot. Just because it tells
you to start at boot, don't mean you have to. It just will take longer to
start that program, but will save resources for programs that you do use
more often. Refrain from buying programs like "FreeMem" or "MemMaker".
They fake Memory, and take up more resources in the processor, not to
mention reduce hard drive space. If you want to increase Memory, then do it
the old fashion way, buy a bigger memory chip(s)

Furthermore, the cooler you can get that Processor, the better it will run.
Also, if you smoke, or have an unusually dust place, make sure you blow your
computer out with some caned air, or a compressor, regularly. Dust and
smoke can be a number one enemy on a computer, causing it to run hot, and
reducing the life of it greatly. I had one computer that had one fan in it,
and it was in the Power supply. Not to mention this was a large tower. So
I placed two more fans inside it. The power supply was blowing from the
inside out. So I put one fan in the front blowing from the outside in. And
a fan above the power supply blowing from the inside out. The effect, the
flow went from the front of the case, out the rear. I also had the heat
sink fan, blowing down on the Processor, causing the heat to blow off the
processor down to the Main board, reflecting off the Main board, and up into
the air flow, going to the back of the case.

Hope that helps,
Rick


  #5   Report Post  
Caroline
 
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"Ricky Eck" wrote
C wrote
Performance seems better. For example, it seems I can dump more tasks on

the
computer at the same time. (This sometimes froze things up.) I am still

getting
some spontaneous Internet disconnects but am now suspecting the phone

lines and
weather variations in my area.

snip

Well, that "Could" increase performance. I would say that putting a power
supply two times the amount then you had was the true increase of
performance. However, the freezing up problem can be caused by MANY things.


Yup.

snip
Furthermore, the cooler you can get that Processor, the better it will run.


To use basic language: I assure you a definite upper limit to the CPU's speed
exists, and once this limit is reached, cooling further will have no effect.




  #6   Report Post  
Ricky Eck
 
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Furthermore, the cooler you can get that Processor, the better it will
run.

To use basic language: I assure you a definite upper limit to the CPU's

speed
exists, and once this limit is reached, cooling further will have no

effect.


Oh, Most defiantly. I mean a system can only go as far as it's limits
(kinda like that old saying "It's always in the last place you look..~


  #7   Report Post  
w_tom
 
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Large power supply does not increase computer performance.
That is classic urban myth. Either computer gets sufficient
power to execute the instruction at same speed - or computer
crashes. The PSU is not a motor. A bigger PSU does not make
the computer work faster. Either the computer executes at the
speed of that master crystal oscillator - or it crashes -
stops working.

Same applies to CPU heat. Again, either CPU runs as crystal
oscillator speed or it crashes. Cooling does not make a CPU
run faster.

Caroline wrote:
"Ricky Eck" wrote
Well, that "Could" increase performance. I would say that
putting a power supply two times the amount then you had was
the true increase of performance. However, the freezing up
problem can be caused by MANY things.


Yup.

snip
Furthermore, the cooler you can get that Processor, the better
it will run.


To use basic language: I assure you a definite upper limit to the
CPU's speed exists, and once this limit is reached, cooling
further will have no effect.

  #8   Report Post  
Ricky Eck
 
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I am still getting
some spontaneous Internet disconnects but am now suspecting the phone

lines and
weather variations in my area.



I forgot to answer this. I wouldn't suspect anything to so with the
computer it's self. See the way how a modem works (I am going to use basic
language here), is a complex language that can be described as different
tones of noise. But there is a method to it's madness. What sounds like
static and noise to us, is really a complex language between the two modems.
If there is any type of interruption between this communication, it could
cause your internet connection to be lost. One big thing, especially on the
older modems, is call waiting. That "Beep" will interrupt the communication
between the two modems. The newer modems comes with a program (sometimes
built into the modem it's self), that can tell the "Beep" of call waiting.
However, the older ones can not tell the difference, therefore gets
confused, and disconnects. Other problems, can be cause by poor wiring in
the phone lines. If you hear static on your line when you talk to someone,
the modem will also. This will cause the modem to get confused, and hang
up. Make sure you have "Error Correction" enabled on the modem. This will,
sometimes, correct the problem.

There is also two different modems on the market. There is the "SoftModem"
a.k.a. "WinModem" That is software drive. This is a modem that you install
all it's software on the Hard Drive. These can be slow, and unreliable.
Mainly because it has to take time to read the programming off the hard
drive. Basically, by the time the modem reads the info off the Hard Drive,
it gives up and hangs up (Especially if you have a slow Hard Drive.) Then
there is a Hard Modem. They are the most reliable. These modems have the
software programmed in on the chip of the Modem it's self. Therefore
reducing the amount of time it takes to read the programming. The only
downfall of these, is software upgrades.

Ever since I used a Hard Modem, I never went back to a WinModem. Hard
modems are more expensive then a WinModem. But well worth it. However,
before you start to replace all this hardware, check in with the phone lines
and company, to see if you have any static or old wiring in your home. Or
even it the "Trunk" to your home is old. 99.9% of connection problems are
bad/old wiring in homes, and just need to be replace. One Apartment I had,
when I used Dial-up, would be filled with static when it rained. The water
would get into the phone lines, and would make the phone terrible for about
3 days.

Hope this helps,
Rick


  #9   Report Post  
LASERandDVDfan
 
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There is also two different modems on the market. There is the "SoftModem"
a.k.a. "WinModem" That is software drive. This is a modem that you install
all it's software on the Hard Drive. These can be slow, and unreliable.


Not necessarily. The reliability of soft modems have greatly improved because
of the amount of power that most computers have today.

The resources that softmodems would use when they are operating would be
negligible if it's used in a machine with a clock in excess of 2 GHz with over
512 MB of RAM. In this case, the only limiting factor would be the quality of
the software used to control the modem.
Unfortunately, this is where most softmodems will fall short. Most cheap
brands of softmodems have sloppily written drivers which will affect how well
the modem can communicate and maintain a connection.

Then
there is a Hard Modem. They are the most reliable. These modems have the
software programmed in on the chip of the Modem it's self.


In some cases, yes. In other cases, no.

Again, it depends on the quality of the controlling software that is written.
In the case of a hardware modem, where all modem control processing is handled
by the modem and not by the host CPU, the software instructions in the modem's
ROM chip or firmware can still be sloppily written. Another factor would be
the quality of the chipset.

I forgot to answer this. I wouldn't suspect anything to so with the
computer it's self. See the way how a modem works (I am going to use basic
language here), is a complex language that can be described as different
tones of noise.


What a modem essentially does is MOdulate the information to be sent into a
simple analogue carrier that can be transmitted through the phone lines. The
computer that receives this signal DEModulates it from an analogue carrier back
into usable computer information. It modulates the information to be sent into
a simpler form and then demodulates information it receives back into something
that can be processed, hence the name (MOdulator DEModulator or MODEM for
short).

One big thing, especially on the
older modems, is call waiting. That "Beep" will interrupt the communication
between the two modems. The newer modems comes with a program (sometimes
built into the modem it's self),


If you have call waiting, you can disable it by dialing a turn-off code,
usually *70, at the dial tone prior to dialing out. This is what the modem is
commanded to do if you configure your ISP software to disable call waiting.
Any modem can do this, new or old, as any modem can be told to dial *70 or
whatever the turn-off code is for your area.

In my area, if the turn-off code is successfully received by the switcher at
the phone company, the dial tone will pulse for a couple of seconds to indicate
that call waiting is disabled.

If you hear static on your line when you talk to someone,
the modem will also. This will cause the modem to get confused, and hang
up.


It's not "confusion," per se. Rather, it's noise that interferes with the
carrier. Sometimes, the modem communication can be recovered. Sometimes, it
can't and you have to reconnect.

Make sure you have "Error Correction" enabled on the modem. This will,
sometimes, correct the problem.


Error correction is more meant to correct errors that can occur as the
information is transmitted through the interim. - Reinhart
  #10   Report Post  
Ricky Eck
 
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Man, I can defiantly tell that you are "New" school. If you noticed at the
beginning of the post I said "I am going to basic language here" meaning
that I was not going to try to confuse the original poster. When I said the
modem gets confused, id didn't want to go into all this description, that
the poster may not understand. You have to remember, that may of the
computer users over the age of 40, and some below, don't understand the
terminology of computers, they just want to fix a problem.

Now, with the *70, many phone companies are starting to charge to use the
*70. You pay a monthly fee to have the option to use the *70 function.
However, the newer modems have a call waiting Function that will alert you
when a call comes in. But no matter if you are "Old" school, or "New"
school, everyone can agree that you modem will work only as good as you
phone connection. I personally have never seen a 56K reach 56K Maybe
someone out there has, but not me.

Rick


"LASERandDVDfan" wrote in message
...
There is also two different modems on the market. There is the

"SoftModem"
a.k.a. "WinModem" That is software drive. This is a modem that you

install
all it's software on the Hard Drive. These can be slow, and unreliable.


Not necessarily. The reliability of soft modems have greatly improved

because
of the amount of power that most computers have today.

The resources that softmodems would use when they are operating would be
negligible if it's used in a machine with a clock in excess of 2 GHz with

over
512 MB of RAM. In this case, the only limiting factor would be the

quality of
the software used to control the modem.
Unfortunately, this is where most softmodems will fall short. Most cheap
brands of softmodems have sloppily written drivers which will affect how

well
the modem can communicate and maintain a connection.

Then
there is a Hard Modem. They are the most reliable. These modems have

the
software programmed in on the chip of the Modem it's self.


In some cases, yes. In other cases, no.

Again, it depends on the quality of the controlling software that is

written.
In the case of a hardware modem, where all modem control processing is

handled
by the modem and not by the host CPU, the software instructions in the

modem's
ROM chip or firmware can still be sloppily written. Another factor would

be
the quality of the chipset.

I forgot to answer this. I wouldn't suspect anything to so with the
computer it's self. See the way how a modem works (I am going to use

basic
language here), is a complex language that can be described as different
tones of noise.


What a modem essentially does is MOdulate the information to be sent into

a
simple analogue carrier that can be transmitted through the phone lines.

The
computer that receives this signal DEModulates it from an analogue carrier

back
into usable computer information. It modulates the information to be sent

into
a simpler form and then demodulates information it receives back into

something
that can be processed, hence the name (MOdulator DEModulator or MODEM for
short).

One big thing, especially on the
older modems, is call waiting. That "Beep" will interrupt the

communication
between the two modems. The newer modems comes with a program (sometimes
built into the modem it's self),


If you have call waiting, you can disable it by dialing a turn-off code,
usually *70, at the dial tone prior to dialing out. This is what the

modem is
commanded to do if you configure your ISP software to disable call

waiting.
Any modem can do this, new or old, as any modem can be told to dial *70 or
whatever the turn-off code is for your area.

In my area, if the turn-off code is successfully received by the switcher

at
the phone company, the dial tone will pulse for a couple of seconds to

indicate
that call waiting is disabled.

If you hear static on your line when you talk to someone,
the modem will also. This will cause the modem to get confused, and hang
up.


It's not "confusion," per se. Rather, it's noise that interferes with the
carrier. Sometimes, the modem communication can be recovered. Sometimes,

it
can't and you have to reconnect.

Make sure you have "Error Correction" enabled on the modem. This will,
sometimes, correct the problem.


Error correction is more meant to correct errors that can occur as the
information is transmitted through the interim. - Reinhart





  #11   Report Post  
Asimov
 
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Default PSU Fan Direction

"LASERandDVDfan" bravely wrote to "All" (15 May 04 23:37:46)
--- on the heady topic of " PSU Fan Direction"

LA From: (LASERandDVDfan)

LA What a modem essentially does is MOdulate the information to be sent
LA into a simple analogue carrier that can be transmitted through the
LA phone lines. The computer that receives this signal DEModulates it
LA from an analogue carrier back into usable computer information. It
LA modulates the information to be sent into a simpler form and then
LA demodulates information it receives back into something that can be
LA processed, hence the name (MOdulator DEModulator or MODEM for short).

Modems do a lot more than make sqweeks and squawks into the phone
line. They compress the data and send it as packets with error
correction. Then the receiving end receives them and decompresses the
data. All the while both ends are monitoring line quality and
negotiating the next transmission. Where a softmodem falls short is in
the lack of its own cpu and a software driver must hog the main cpu to
emulate the modem's cpu. In a very powerful pc this isn't usually too
bad but in general mostly all other running programs suffer.

The easiest analogy of this is an audio soundcard where the
instruments use emulated wavetable synthesis to drive the D/A
channels. Usually these drivers will emulate some synthesizer, like a
Yamaha etc. This works pretty well most of the time but when the
system starts running out of resources, the synthesizer starts to lose
instruments, go out of tune, or do other weird sounding things.

No software can beat a hardware system. Especially not a winmodem.

Asimov
******

.... A fail-safe circuit will destroy others.

  #12   Report Post  
Caroline
 
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"Ricky Eck" wrote
C wrote
I am still getting
some spontaneous Internet disconnects but am now suspecting the phone

lines and
weather variations in my area.



I forgot to answer this. I wouldn't suspect anything to so with the
computer it's self. See the way how a modem works (I am going to use basic
language here), is a complex language that can be described as different
tones of noise. But there is a method to it's madness.


It's not madness. It's not complex. It is engineering, in which I have three
bachelor's and higher degrees. ;-)

What sounds like
static and noise to us, is really a complex language between the two modems.
If there is any type of interruption between this communication, it could
cause your internet connection to be lost.


Yup.

snip obvious

This Gateway 900c desktop as purchased in early September, 2001 has an
integrated modem. For a month I had terrible problems trying to get it to
connect to the internet. I spent dozens of hours working with Gateway and
America Online (my ISP then) to figure out why. They kept blaming each other for
the problem, of course. Finally a Gateway tech and I narrowed it down to the
strong possibility that the integrated modem was too sensitive to my older
home's phone line noise. Gateway said, "Too bad your house can't make use of our
superior modem." I said, "Not so fast. Your modem is not superior; my old
computer's external modem works fine and is the superior one. I'm sending your
computer back for a full refund, per the warranty." The tech turned me over to a
manager who agreed to pay for an external modem. I kept the computer.

I have used the external modem ever since.

I did a modem noise check of my phone lines (in my new home) several months ago.
It was somewhat high but then things settled down and I wasn't getting
disconnected. Now the problem has returned.

What I probably should do to troubleshoot further is graph disconnects per day
vs. weather trends. Also, maybe I'll try the internal modem.

Anyway, thanks for the suggestions. I have ideas where to go with this. And as I
mentioned in the other thread here on power supplies, my computer is far from
crippled.


  #13   Report Post  
LASERandDVDfan
 
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Gateway said, "Too bad your house can't make use of our
superior modem." I said, "Not so fast. Your modem is not superior


The only thing that would make the Gateway integrated modem superior is that
it's connected directly to the southgate on the motherboard through a local bus
as opposed to working through a PCI bus, USB port, or a parallel port.

Other than that, I'm willing to bet it's a softmodem with a cruddy chipset,
like a PCTel or a Motorola or an Intel, and running with a sloppy set of
drivers.

The tech turned me over to a
manager who agreed to pay for an external modem. I kept the computer.

I have used the external modem ever since.


Good choice. All external modems are going to be hardware-based, at least for
the parallel port variety.


I did a modem noise check of my phone lines (in my new home) several months
ago.
It was somewhat high but then things settled down and I wasn't getting
disconnected. Now the problem has returned.


Call the phone company and have them correct the problem. They may perform a
test and say that it's okay, but tell them that this is for a computer modem
and while the line may be suitable for regular conversation, it is apparently
too noisy and, therefore, unacceptable for use with a modem.

You're paying for their services, so make them deliver you that service in the
best way possible.

What I probably should do to troubleshoot further is graph disconnects per
day
vs. weather trends. Also, maybe I'll try the internal modem.


If the problem is with the phone line, switching to an internal modem won't
help. All it will do is take one less object off your desk and free up one
plug outlet.

If you are using a parallel port connection, make sure that your BIOS is set to
allow two-way parallel port communication and that your cable is also suitable
for that purpose.

If you are using a USB modem, make sure that you have the most up to date
drivers for your USB controller and that it supports the USB mode that the
modem requires. If your modem requires USB 2.0, then your USB port and cabling
must support USB 2.0 and your BIOS must be set to allow this mode of
communication, if available.

Make sure that your modem does not have problems with using system resources,
such as I/O addresses and interrupt requests. A modem will be assigned a COM
port which means that resources associated with that COM port should be used by
the modem only. Your modem is most likely plug-n-play so it will be assigned
the necessary resources by your operating system automatically, but resource
conflicts can still occur.

Make sure your ISP software is configured to use your modem properly.

Other things you could try is to use a different telephone cord that is the
shortest possible for your needs. Also, be sure that the connection is as
direct to the phone line as possible. You can get away with running it through
one surge suppressor, though. Don't use RF-based plug-in phone jack
extensions, particularly those that are not clearly labeled as intended for use
with data communications. - Reinhart
  #14   Report Post  
Asimov
 
Posts: n/a
Default PSU Fan Direction

"Caroline" bravely wrote to "All" (16 May 04 01:36:50)
--- on the heady topic of " PSU Fan Direction"

Ca From: "Caroline"

Ca "Ricky Eck" wrote
Ca C wrote
I am still getting
some spontaneous Internet disconnects but am now suspecting the phone

lines and
weather variations in my area.



I forgot to answer this. I wouldn't suspect anything to so with the
computer it's self. See the way how a modem works (I am going to use basic
language here), is a complex language that can be described as different
tones of noise. But there is a method to it's madness.


Ca It's not madness. It's not complex. It is engineering, in which I have
Ca three bachelor's and higher degrees. ;-)

What sounds like
static and noise to us, is really a complex language between the two modems.
If there is any type of interruption between this communication, it could
cause your internet connection to be lost.


Ca Yup.

Ca snip obvious

Ca This Gateway 900c desktop as purchased in early September, 2001 has an
Ca integrated modem. For a month I had terrible problems trying to get it
Ca to connect to the internet. I spent dozens of hours working with
Ca Gateway and America Online (my ISP then) to figure out why. They kept
Ca blaming each other for the problem, of course. Finally a Gateway tech
Ca and I narrowed it down to the strong possibility that the integrated
Ca modem was too sensitive to my older home's phone line noise. Gateway
Ca said, "Too bad your house can't make use of our superior modem." I
Ca said, "Not so fast. Your modem is not superior; my old computer's
Ca external modem works fine and is the superior one. I'm sending your
Ca computer back for a full refund, per the warranty." The tech turned me
Ca over to a manager who agreed to pay for an external modem. I kept the
Ca computer.
Ca I have used the external modem ever since.

Ca I did a modem noise check of my phone lines (in my new home) several
Ca months ago. It was somewhat high but then things settled down and I
Ca wasn't getting disconnected. Now the problem has returned.

Ca What I probably should do to troubleshoot further is graph disconnects
Ca per day vs. weather trends. Also, maybe I'll try the internal modem.

Ca Anyway, thanks for the suggestions. I have ideas where to go with
Ca this. And as I mentioned in the other thread here on power supplies, my
Ca computer is far from crippled.

Some modems have trouble with being too sensitive. I've heard of a
trick of using a variable L-pot to attenuate the phone line signal the
modem receives. I've never had to use this tip so I can't say.

However a common cause of noise in a phone line is dirty RJ phone
connections. Replace those that cleaning doesn't seem to help.
There can be a lot of connectors on a phone line and each is a
potential source of noise.

Asimov
******

.... If plugging it in doesn't help, turn it on.

  #15   Report Post  
Franc Zabkar
 
Posts: n/a
Default PSU Fan Direction

On Sun, 16 May 2004 01:36:50 GMT, "Caroline"
put finger to keyboard and
composed:

This Gateway 900c desktop as purchased in early September, 2001 has an
integrated modem. For a month I had terrible problems trying to get it to
connect to the internet. I spent dozens of hours working with Gateway and
America Online (my ISP then) to figure out why. They kept blaming each other for
the problem, of course. Finally a Gateway tech and I narrowed it down to the
strong possibility that the integrated modem was too sensitive to my older
home's phone line noise. Gateway said, "Too bad your house can't make use of our
superior modem." I said, "Not so fast. Your modem is not superior; my old
computer's external modem works fine and is the superior one. I'm sending your
computer back for a full refund, per the warranty." The tech turned me over to a
manager who agreed to pay for an external modem. I kept the computer.

I have used the external modem ever since.

I did a modem noise check of my phone lines (in my new home) several months ago.
It was somewhat high but then things settled down and I wasn't getting
disconnected. Now the problem has returned.

What I probably should do to troubleshoot further is graph disconnects per day
vs. weather trends. Also, maybe I'll try the internal modem.

Anyway, thanks for the suggestions. I have ideas where to go with this. And as I
mentioned in the other thread here on power supplies, my computer is far from
crippled.


Most modems can produce a last call diagnostic report. This includes
data such as Tx/Rx signal levels, Tx/Rx error rates, S/N ratio,
numbers of speedshifts and retrains, etc.

http://www.modemsite.com/56k/x2-inf.asp
http://www.modemsite.com/56k/x2-hyperterm.asp
http://www.modemsite.com/56k/usehyper.asp
http://www.modemsite.com/56k/diag.asp
http://www.modemsite.com/56k/trouble.asp

My own Rockwell chipped modem produces the data below. Notice these
highly abbreviated data for a good session ...

TX/RX I-Frame count : 17654/21091
TX/RX I-Frame error count : 29/14
TX Rate (Last/Init/Min/Max) : 28800/26400/26400/28800
RX Rate (Last/Init/Min/Max) : 46667/46667/45333/46667
Modulation/Protocol/Compression : V.90/LAPM/V.42bis
Retrains (Issued/Granted/Fast) : 0/0/5
Renegs (Issued/Granted) : 2/0
Retrans per frame/Frames rejected : 1/14
Error control timeouts in TX : 16
Error control NAKs received : 29
Termination Cause : Dte Hangup Command

.... a not so good session ...

TX/RX I-Frame count : 10268/34101
TX/RX I-Frame error count : 15/47
TX Rate (Last/Init/Min/Max) : 28800/26400/26400/28800
RX Rate (Last/Init/Min/Max) : 38667/42667/38667/42667
Modulation/Protocol/Compression : V.90/LAPM/V.42bis
Retrains (Issued/Granted/Fast) : 0/0/0
Renegs (Issued/Granted) : 3/0
Retrans per frame/Frames rejected : 1/47
Error control timeouts in TX : 7
Error control NAKs received : 15
Termination Cause : Dte Hangup Command

.... and a bad session (water in the cable) ...

TX/RX I-Frame count : 784/4482
TX/RX I-Frame error count : 23/211
TX Rate (Last/Init/Min/Max) : 26400/26400/26400/28800
RX Rate (Last/Init/Min/Max) : 38667/44000/33333/44000
Modulation/Protocol/Compression : V.90/LAPM/V.42bis
Retrains (Issued/Granted/Fast) : 0/1/2
Renegs (Issued/Granted) : 12/0
Retrans per frame/Frames rejected : 8/211
Error control timeouts in TX : 16
Error control NAKs received : 23
Termination Cause : Retrain Failed


Notice that the initial CONNECT speed is not a reliable indicator of
modem performance, as modems will speedshift as line conditions
change. Notice also that the modem can tell you the reason for
disconnect. For example, a "Termination Cause" of "Disconnect Frame
Received" indicates that your ISP kicked you off.


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


  #16   Report Post  
Franc Zabkar
 
Posts: n/a
Default PSU Fan Direction

On Sat, 15 May 2004 17:06:51 GMT, "Ricky Eck"
put finger to keyboard and composed:

There is also two different modems on the market.


Actually, there are three types, "soft", controllerless, and "hard"
(controller based). Softmodems have a DAA (telephone line interface),
controllerless modems have a DAA and DSP (digital signal processor),
and "hard" modems have a DAA, DSP, and controller.

Among other things, a modem's controller handles AT command parsing,
UART emulation, data compression and error correction. These functions
do not impact significantly on the host CPU. OTOH, the functions of a
DSP are highly CPU intensive, so a softmodem (which emulates the DSP
in software) may impact noticeably on CPU performance.

There is the "SoftModem" a.k.a. "WinModem".


Actually, to be pedantic, "Winmodem" is a USR trademark and refers to
their line of controllerless modems.

Examples of softmodem chipsets are PCtel HSP, Motorola SM56,
Smartlink, and Conexant HSF. Controllerless examples include Conexant
HCF, Intel HaM, Lucent Win Modem, and USR Winmodem.


- Franc Zabkar
--
Please remove one 's' from my address when replying by email.
  #17   Report Post  
Caroline
 
Posts: n/a
Default PSU Fan Direction

"Caroline" wrote
[After installing a power supply twice the watt rating of the old power
supply--]
Performance seems better. For example, it seems I can dump more tasks on the
computer at the same time. (This sometimes froze things up.) I am still

getting
some spontaneous Internet disconnects but am now suspecting the phone lines

and
weather variations in my area.


To be complete, I have an update:

I switched to the integrated modem ("56K AC-Link Voice Modem") two days ago. I
also switched the telephone access number I use with Earthlink. My rate of
disconnects has gone down considerably--only one in the last 2.5 days, vs.
half-a-dozen or more daily in the recent past. (My time on the computer and
typing messages did not change notably in the last 2.5 days.)

I'll switch back to the external modem soon and see if the problem was a
"crowded" (or otherwise deficient-in-some-way) access number.


  #18   Report Post  
w_tom
 
Posts: n/a
Default PSU Fan Direction

Did you make the direct connection to NID - to determine if
noise is from internal or external source? Demonstrated is
one modem that tends to be more noise resistant (has a better
DSP algorithm) than the other. Test still does not identify
source of noise and resulting disconnect. You still have
disconnects. Therefore you are not yet identifying reason for
failure. Long before we discuss fixing the problem, first
concentrate on identifying the problem. Hyperterminal has
always been a powerful tool for identifying a modem verse line
problem in part because it is so simple to use and because it
provides fundamental facts without the summarizations (basic
data removed) from Windows.

Caroline wrote:
To be complete, I have an update:

I switched to the integrated modem ("56K AC-Link Voice Modem")
two days ago. I also switched the telephone access number I use
with Earthlink. My rate of disconnects has gone down
considerably--only one in the last 2.5 days, vs.
half-a-dozen or more daily in the recent past. (My time on the
computer and typing messages did not change notably in the last
2.5 days.)

I'll switch back to the external modem soon and see if the
problem was a "crowded" (or otherwise deficient-in-some-way)
access number.

  #19   Report Post  
Vidar L.
 
Posts: n/a
Default PSU Fan Direction

Caroline wrote:

Or should I figure out a way to reverse the fan flow direction in the new power
supply?

To reverse the airstream, you have to turn the fans, by opening the psu,
and turning it around. The standard now is front intake with or without
fans, and only psu exhaust fan, or another additional exhaust fan.

I'm having 2 papst 80mm fans in front, running on 6 v, and the psu
sucking out. That is however to little...


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