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What is the potential value of a used 400W ATX power suppy.



 
 
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  #1  
Old January 6th 19, 12:55 AM posted to alt.comp.hardware
Norm X[_2_]
external usenet poster
 
Posts: 85
Default What is the potential value of a used 400W ATX power suppy.

I have a PC box with the same MOBO since 2008, ten years. Every other
component has been upgraded , serviced or replaced. With patience,
technology improves and new parts are better and cheaper. My original PS was
250W which was abused by excessive power load. I bought a 400W replacement.
After many years of unfailing service, It developed an annoying sympathetic
vibration that I serviced. Don't worry about the warning stickers. I opened
the sealed case with its narrow strips of anti-vibration Teflon on the
interlocking edges. So I was careful to insure that it went back together
correct. It is always best to wait a bit before making a new diagnosis. The
sympathetic vibration was cured. In the mean time I ordered a new 400W ATX
power supply but have hesitated to replace the old one. I turned the desktop
PC off a few days ago and now the PS gives a mild hum. This power supply is
working well electrically and the hum would not be noticed if the PC was in
its own room. There are poor starving children in Africa whose lives would
be enriched with a replacement after market PS.

So my question is solicit humanitarian advice. Would I be better to donate
to charity at the workplace of poor starving computer techs, or to sell it
on Craiglist?

Thanks for an opinion.



--- news://freenews.netfront.net/ - complaints: ---
  #2  
Old January 6th 19, 10:42 AM posted to alt.comp.hardware
Paul[_26_]
external usenet poster
 
Posts: 958
Default What is the potential value of a used 400W ATX power suppy.

Norm X wrote:
I have a PC box with the same MOBO since 2008, ten years. Every other
component has been upgraded , serviced or replaced. With patience,
technology improves and new parts are better and cheaper. My original PS was
250W which was abused by excessive power load. I bought a 400W replacement.
After many years of unfailing service, It developed an annoying sympathetic
vibration that I serviced. Don't worry about the warning stickers. I opened
the sealed case with its narrow strips of anti-vibration Teflon on the
interlocking edges. So I was careful to insure that it went back together
correct. It is always best to wait a bit before making a new diagnosis. The
sympathetic vibration was cured. In the mean time I ordered a new 400W ATX
power supply but have hesitated to replace the old one. I turned the desktop
PC off a few days ago and now the PS gives a mild hum. This power supply is
working well electrically and the hum would not be noticed if the PC was in
its own room. There are poor starving children in Africa whose lives would
be enriched with a replacement after market PS.

So my question is solicit humanitarian advice. Would I be better to donate
to charity at the workplace of poor starving computer techs, or to sell it
on Craiglist?

Thanks for an opinion.


I would only sell the PSU, if I thought it wasn't going
to damage someones PC.

The noise could be a worn cooling fan. On some PSUs the
fan is connectorized and you can unplug it and replace it
with a new fan. The fan will not be stamped with sufficient
information to make shopping for a new fan easy.

The new PSU will be more efficient, and you can pretend
the electricity you're saving, is helping to pay for the
discarded PSU.

If you paid $40 to $60 for the PSU originally, allowing
for depreciation the asking price won't be that much,
and might not be worth your time dealing with a buyer.
A buyer could locate a really bad $20 PSU for new for
example. Your sale will be competing with that as a
notion of a purchase. Check Newegg to see what the absolute
cheapest new PSU would cost. That's what you're competing
against.

If the PSU was a unit with "brand name recognition" it
might fetch more on resale.

The fan in a PSU would roughly be rated for three years
continuous operation. If you use the PC eight hours a day,
that gives the fan a nine year life. The buyer should be
taking that into account when buying the PSU, that the
fan will need replacement at some point. And a good fan
at a local retailer, will likely cost as much as you're
going to list that PSU on Craigslist.

My favorite fan (Vantec Stealth) is no longer for
sale, and my computer store stocks "smelly blue LED crap"
for fans, so I cannot rely on the store for cooling
solutions. The electronics store on the other hand,
has noisy "high" speed fans in the right size... for
about $25 a piece. Perfectly serviceable fans, but
too expensive for a to-be-sold PSU repair job. The
fan in the PSU is likely a "low" or a "medium".
Some PSUs have two fans.

The electrolytic caps in the PSU, at room temperature,
are rated for around a 17 year service life. The rubber
bung on the bottom can dry out and allow the electrolyte
inside to dry as well. So that's a recommended life figure
from a cap maker, just to give some idea what they think
they're good for. They likely last longer than that.
The rest of the PSU might last a good long time if
it wasn't for caps.

Paul
  #3  
Old February 10th 19, 03:40 AM posted to alt.comp.hardware
Norm X[_2_]
external usenet poster
 
Posts: 85
Default What is the potential value of a used 400W ATX power suppy.

"Paul" wrote, on Sunday, January 06, 2019 2:42 AM
Norm X wrote:
I have a PC box with the same MOBO since 2008, ten years. Every other
component has been upgraded , serviced or replaced. With patience,
technology improves and new parts are better and cheaper. My original PS
was 250W which was abused by excessive power load. I bought a 400W
replacement. After many years of unfailing service, It developed an
annoying sympathetic vibration that I serviced. Don't worry about the
warning stickers. I opened the sealed case with its narrow strips of
anti-vibration Teflon on the interlocking edges. So I was careful to
insure that it went back together correct. It is always best to wait a
bit before making a new diagnosis. The sympathetic vibration was cured.
In the mean time I ordered a new 400W ATX power supply but have hesitated
to replace the old one. I turned the desktop PC off a few days ago and
now the PS gives a mild hum. This power supply is working well
electrically and the hum would not be noticed if the PC was in its own
room. There are poor starving children in Africa whose lives would be
enriched with a replacement after market PS.

So my question is solicit humanitarian advice. Would I be better to
donate to charity at the workplace of poor starving computer techs, or to
sell it on Craiglist?

Thanks for an opinion.


I would only sell the PSU, if I thought it wasn't going
to damage someones PC.

The noise could be a worn cooling fan. On some PSUs the
fan is connectorized and you can unplug it and replace it
with a new fan. The fan will not be stamped with sufficient
information to make shopping for a new fan easy.

The new PSU will be more efficient, and you can pretend
the electricity you're saving, is helping to pay for the
discarded PSU.

If you paid $40 to $60 for the PSU originally, allowing
for depreciation the asking price won't be that much,
and might not be worth your time dealing with a buyer.
A buyer could locate a really bad $20 PSU for new for
example. Your sale will be competing with that as a
notion of a purchase. Check Newegg to see what the absolute
cheapest new PSU would cost. That's what you're competing
against.

If the PSU was a unit with "brand name recognition" it
might fetch more on resale.

The fan in a PSU would roughly be rated for three years
continuous operation. If you use the PC eight hours a day,
that gives the fan a nine year life. The buyer should be
taking that into account when buying the PSU, that the
fan will need replacement at some point. And a good fan
at a local retailer, will likely cost as much as you're
going to list that PSU on Craigslist.

My favorite fan (Vantec Stealth) is no longer for
sale, and my computer store stocks "smelly blue LED crap"
for fans, so I cannot rely on the store for cooling
solutions. The electronics store on the other hand,
has noisy "high" speed fans in the right size... for
about $25 a piece. Perfectly serviceable fans, but
too expensive for a to-be-sold PSU repair job. The
fan in the PSU is likely a "low" or a "medium".
Some PSUs have two fans.

The electrolytic caps in the PSU, at room temperature,
are rated for around a 17 year service life. The rubber
bung on the bottom can dry out and allow the electrolyte
inside to dry as well. So that's a recommended life figure
from a cap maker, just to give some idea what they think
they're good for. They likely last longer than that.
The rest of the PSU might last a good long time if
it wasn't for caps.

Paul


Thanks Paul, for the advice.

After I did the service work, the old PSU worked sufficiently well that I
kept it in that PC for a month, even though a new Coolmax 400W I-400 had
been delivered. IMHO mechanical problems are a precursor to electrical
problem. One day, after I powered PC down then up, I was informed of a RAM
problems. Not so I thought, it's brand new 8GB RAM that I tested for hours
and hours. It is definitely the PSU that failed its purpose to deliver good
clean power. I disassembled that PC, removed the old PSU and screwed in the
new Coolmax 400W I-400. Then I discovered the Coolmax did not provide all
the connectors I need. I didn't know that! I thought standards were forever?
Maybe I can get the problem solved tomorrow.

So now I have one nonfunctional Dynex 400W PSU with no value and one Coolmax
that has no value to me, but may have trade value at the shop. I like to
keep information continuity going, so now I will be distressed until that PC
is working.



--- news://freenews.netfront.net/ - complaints: ---
  #4  
Old February 10th 19, 04:27 AM posted to alt.comp.hardware
Paul[_26_]
external usenet poster
 
Posts: 958
Default What is the potential value of a used 400W ATX power suppy.

Norm X wrote:


Thanks Paul, for the advice.

After I did the service work, the old PSU worked sufficiently well that I
kept it in that PC for a month, even though a new Coolmax 400W I-400 had
been delivered. IMHO mechanical problems are a precursor to electrical
problem. One day, after I powered PC down then up, I was informed of a RAM
problems. Not so I thought, it's brand new 8GB RAM that I tested for hours
and hours. It is definitely the PSU that failed its purpose to deliver good
clean power. I disassembled that PC, removed the old PSU and screwed in the
new Coolmax 400W I-400. Then I discovered the Coolmax did not provide all
the connectors I need. I didn't know that! I thought standards were forever?
Maybe I can get the problem solved tomorrow.

So now I have one nonfunctional Dynex 400W PSU with no value and one Coolmax
that has no value to me, but may have trade value at the shop. I like to
keep information continuity going, so now I will be distressed until that PC
is working.


The number of cables is partially proportional to the
capacity of the power supply.

Maybe a 1200W supply would have eight PCI Express video
card connectors on four cables.

Whereas a 350W supply, the designer of it might not put
any video card connectors on it. Because it isn't expected
the supply could power a discrete video card with one
or more external connectors.

There are SATA and Molex connectors. Usually a supply
needs at least one string with Molex on it, for backward
compatibility, plus at least one more with SATA 15 pin power
ones. Preferably two SATA chains, since in a typical build
there might be two clusters of storage devices.

Yes, before you buy, it's a good idea to sus out the
cabling.

There are no standards for documentation or for being
helpful to customers. You would have thought in a fully
connected world, it would be different.

Two dimensions of the ATX supply, on the faceplate side,
are standard. The "depth" dimension is a function of
capacity. Too long of a supply, the cable bundle can
"bump" into the back of the optical drive.

This site has some materials to help identifying
what's on each of your supplies.

http://www.playtool.com/pages/psucon...onnectors.html

Paul
  #5  
Old February 21st 19, 07:04 AM posted to alt.comp.hardware
Norm X[_2_]
external usenet poster
 
Posts: 85
Default What is the potential value of a used 400W ATX power suppy.

[snippage]

After I did the service work, the old PSU worked sufficiently well that I
kept it in that PC for a month, even though a new Coolmax 400W I-400 had
been delivered. IMHO mechanical problems are a precursor to electrical
problem. One day, after I powered PC down then up, I was informed of a
RAM problems. Not so I thought, it's brand new 8GB RAM that I tested for
hours and hours. It is definitely the PSU that failed its purpose to
deliver good clean power. I disassembled that PC, removed the old PSU and
screwed in the new Coolmax 400W I-400. Then I discovered the Coolmax did
not provide all the connectors I need. I didn't know that! I thought
standards were forever? Maybe I can get the problem solved tomorrow.

So now I have one nonfunctional Dynex 400W PSU with no value and one
Coolmax that has no value to me, but may have trade value at the shop. I
like to keep information continuity going, so now I will be distressed
until that PC is working.


The number of cables is partially proportional to the
capacity of the power supply.

Maybe a 1200W supply would have eight PCI Express video
card connectors on four cables.

Whereas a 350W supply, the designer of it might not put
any video card connectors on it. Because it isn't expected
the supply could power a discrete video card with one
or more external connectors.

There are SATA and Molex connectors. Usually a supply
needs at least one string with Molex on it, for backward
compatibility, plus at least one more with SATA 15 pin power
ones. Preferably two SATA chains, since in a typical build
there might be two clusters of storage devices.

Yes, before you buy, it's a good idea to sus out the
cabling.

There are no standards for documentation or for being
helpful to customers. You would have thought in a fully
connected world, it would be different.

Two dimensions of the ATX supply, on the faceplate side,
are standard. The "depth" dimension is a function of
capacity. Too long of a supply, the cable bundle can
"bump" into the back of the optical drive.

This site has some materials to help identifying
what's on each of your supplies.

http://www.playtool.com/pages/psucon...onnectors.html

Paul


Thanks Paul. The link to article you gave was useful. A nice man at a repair
shop gave me a short Molex to six pin GPU power adapter cable. I gave him
RAM I could not sell. I was confused a bit by an 8 pin connector that could
be split into two identical four pin connectors on the new Amazon Coolmax
PSU. I left the old Dynex PSU with the shop for refurbishing. That may have
been premature. I used scotch tape to identify all the power connectors I
used. The wire colors tell what is correct. Either I get a call from the
shop to tell me all is A OK, or I can study the article you gave to satisfy
my concern. I don't want to power up unless everything is electrically
correct.



--- news://freenews.netfront.net/ - complaints: ---
  #6  
Old February 21st 19, 08:07 AM posted to alt.comp.hardware
Paul[_26_]
external usenet poster
 
Posts: 958
Default What is the potential value of a used 400W ATX power suppy.

Norm X wrote:

Thanks Paul. The link to article you gave was useful. A nice man at a repair
shop gave me a short Molex to six pin GPU power adapter cable. I gave him
RAM I could not sell. I was confused a bit by an 8 pin connector that could
be split into two identical four pin connectors on the new Amazon Coolmax
PSU. I left the old Dynex PSU with the shop for refurbishing. That may have
been premature. I used scotch tape to identify all the power connectors I
used. The wire colors tell what is correct. Either I get a call from the
shop to tell me all is A OK, or I can study the article you gave to satisfy
my concern. I don't want to power up unless everything is electrically
correct.


If you use the short Molex to six pin GPU, note that the Molex connector
has enough ampacity to do the job, but then there's nothing left over
for hard drives. For example, doing this would be marginal, from the
HDD-requirements point of view. The GPU on the video card will likely
tolerate the tolerances on the 12V rail if done like this.

PSU
|
+--- HDD 1.5A
|
+--- HDD 1.5A
|
|
+--- adapter --- PCIe 12V @ 6A for 75W video card

What can happen if you do that, is the HDD may "spin-down" in
mid-session, because the voltage on the cable drops to around 11V
instead of 12V. The HDD is doing an "emergency shutdown", as it thinks
the PSU is about to turn off the power.

If using the adapter, you might do this. Now, if the cable voltage
drops to 11V because of ohms law, the video card won't shut off.

PSU
|
+---
|
+---
|
|
+--- adapter --- PCIe 12V @ 6A for 75W video card

Some of those adapters, come with two Molex. And they're intended
to be used like this. You connect each molex to a different chain,
in an attempt to spread the load, so the wires from the PSU work in
parallel and the voltage drop is slightly less.

PSU ---------------+
| |
+--- ---+
| |
+--- ---+
| |
| |
+---X X---+
\ /
+--+--+
|
PCIe 2x3 12V @ 6A

On a modern desktop PSU, the two wire looms in question
are likely off the same output, so you're not putting
outputs in parallel.

*******

The 2x4 that splits into two 2x2 is for ATX12V by the processor socket.

Traditionally, a Pentium 4 motherboard back in the day, had a 2x2
with two yellow wires and two black wires. The connector was keyed
by the shape of the nylon shroud around each pin. The motherboard
manual, on the good ones, would even show which pins where
+12V (yellow) and which were ground (black).

Later, there were several standards for server processor connectors
using 2x4 pins instead. Those don't split. And those are not
compatible with desktops either. Fortunately, you don't run into
those too often when buying desktop power supplies.

Enthusiast motherboards need more than 144W. Or 12V @ 12A on the 2x2
ATX12V. To solve that need, they combined more yellow and black wires.
By using a 2x4 with four yellow and four black, they get room
for 12V @ 24A to flow, or 288W. There are still some overclocking
experiments that draw more power than that (D-805 at 4GHz), but then
you'd probably be melting the motherboard when doing that anyway :-)

There is a 2x4 that splits into a 2x3 and a 2x1. That's PCI Express
and solving both 2x4 and 2x3 input requirements. One of the pins
involved there is a "sense" pin rather than a "current flow" pin,
and tells the video card a proper 2x4 PCIe power was plugged in.

You should have been able to see those on Playtool.

This is the ATX12V that splits in two pieces for usage with
legacy motherboards (near the CPU socket).

http://www.playtool.com/pages/psucon...plus4index.jpg

Whereas this is the PCI Express that does 2x3 or 2x4 PCIe power.

http://www.playtool.com/pages/psucon...plus2index.jpg

The shroud on the connector, is intended to prevent inappropriate
combinations. On the ATX12V that splits in half, one half has
the "right" shape for the 2x2 on an old motherboard. The second
half is the extension portion, and is the "wrong" shape to fit
a 2x2 on its own. This is purely arbitrary - what matters is
that no yellow wires on the PSU end, touch pins intended for ground,
and that causes a short and causes the PSU to shut off (if you're lucky).

This is a picture I drew previously. The drawing shows the shapes
in the plastic ends of the connectors involved for ATX12V.

ATX12V 4/8

TTTTTT TTTTTT End view of connector pair
___ ___ ___ ___ showing shapes which help
| | | | | | | | control mating only one way.
| | | | | | | |
\_/ --- \_/ \_/ You will be using the *left* connector in pic.
___ ___ ___ ___ The right connector is used if
| | | | | | | | the motherboard had a 2x4 and room
| | | | | | | | for all eight pins.
--- \_/ \_/ \_/
TTTTTT is the tab which latches to
|| a feature on the side of the connector
\||/ on the motherboard and provides a
\/ visual cue on how to do it.
___ ___
| | | | Normal motherboards have just 2x2 [144 watt]
| | | | and have a tab for the latch on the
\_/ --- PSU end to attach to. The right-hand
___ ___ one above would not insert unless you
| | | | had an enthusiast 2x4 on the motherboard
| | | | with it's (approximate) 288W rating
--- \_/

HTH,
Paul
  #7  
Old February 25th 19, 02:09 AM posted to alt.comp.hardware
Norm X[_2_]
external usenet poster
 
Posts: 85
Default What is the potential value of a used 400W ATX power suppy.

[snippage]

Thanks Paul. The link to article you gave was useful. A nice man at a
repair shop gave me a short Molex to six pin GPU power adapter cable. I
gave him RAM I could not sell. I was confused a bit by an 8 pin connector
that could be split into two identical four pin connectors on the new
Amazon Coolmax PSU. I left the old Dynex PSU with the shop for
refurbishing. That may have been premature. I used scotch tape to
identify all the power connectors I used. The wire colors tell what is
correct. Either I get a call from the shop to tell me all is A OK, or I
can study the article you gave to satisfy my concern. I don't want to
power up unless everything is electrically correct.


If you use the short Molex to six pin GPU, note that the Molex connector
has enough ampacity to do the job, but then there's nothing left over
for hard drives. For example, doing this would be marginal, from the
HDD-requirements point of view. The GPU on the video card will likely
tolerate the tolerances on the 12V rail if done like this.

PSU
|
+--- HDD 1.5A
|
+--- HDD 1.5A
|
|
+--- adapter --- PCIe 12V @ 6A for 75W video card

What can happen if you do that, is the HDD may "spin-down" in
mid-session, because the voltage on the cable drops to around 11V
instead of 12V. The HDD is doing an "emergency shutdown", as it thinks
the PSU is about to turn off the power.

If using the adapter, you might do this. Now, if the cable voltage
drops to 11V because of ohms law, the video card won't shut off.

PSU
|
+---
|
+---
|
|
+--- adapter --- PCIe 12V @ 6A for 75W video card

Some of those adapters, come with two Molex. And they're intended
to be used like this. You connect each molex to a different chain,
in an attempt to spread the load, so the wires from the PSU work in
parallel and the voltage drop is slightly less.

PSU ---------------+
| |
+--- ---+
| |
+--- ---+
| |
| |
+---X X---+
\ /
+--+--+
|
PCIe 2x3 12V @ 6A

On a modern desktop PSU, the two wire looms in question
are likely off the same output, so you're not putting
outputs in parallel.

*******

The 2x4 that splits into two 2x2 is for ATX12V by the processor socket.

Traditionally, a Pentium 4 motherboard back in the day, had a 2x2
with two yellow wires and two black wires. The connector was keyed
by the shape of the nylon shroud around each pin. The motherboard
manual, on the good ones, would even show which pins where
+12V (yellow) and which were ground (black).

Later, there were several standards for server processor connectors
using 2x4 pins instead. Those don't split. And those are not
compatible with desktops either. Fortunately, you don't run into
those too often when buying desktop power supplies.

Enthusiast motherboards need more than 144W. Or 12V @ 12A on the 2x2
ATX12V. To solve that need, they combined more yellow and black wires.
By using a 2x4 with four yellow and four black, they get room
for 12V @ 24A to flow, or 288W. There are still some overclocking
experiments that draw more power than that (D-805 at 4GHz), but then
you'd probably be melting the motherboard when doing that anyway :-)

There is a 2x4 that splits into a 2x3 and a 2x1. That's PCI Express
and solving both 2x4 and 2x3 input requirements. One of the pins
involved there is a "sense" pin rather than a "current flow" pin,
and tells the video card a proper 2x4 PCIe power was plugged in.

You should have been able to see those on Playtool.

This is the ATX12V that splits in two pieces for usage with
legacy motherboards (near the CPU socket).

http://www.playtool.com/pages/psucon...plus4index.jpg

Whereas this is the PCI Express that does 2x3 or 2x4 PCIe power.

http://www.playtool.com/pages/psucon...plus2index.jpg

The shroud on the connector, is intended to prevent inappropriate
combinations. On the ATX12V that splits in half, one half has
the "right" shape for the 2x2 on an old motherboard. The second
half is the extension portion, and is the "wrong" shape to fit
a 2x2 on its own. This is purely arbitrary - what matters is
that no yellow wires on the PSU end, touch pins intended for ground,
and that causes a short and causes the PSU to shut off (if you're lucky).

This is a picture I drew previously. The drawing shows the shapes
in the plastic ends of the connectors involved for ATX12V.

ATX12V 4/8

TTTTTT TTTTTT End view of connector pair
___ ___ ___ ___ showing shapes which help
| | | | | | | | control mating only one way.
| | | | | | | |
\_/ --- \_/ \_/ You will be using the *left*
connector in pic.
___ ___ ___ ___ The right connector is used if
| | | | | | | | the motherboard had a 2x4 and room
| | | | | | | | for all eight pins.
--- \_/ \_/ \_/
TTTTTT is the tab which latches to
|| a feature on the side of the
connector
\||/ on the motherboard and provides a
\/ visual cue on how to do it.
___ ___
| | | | Normal motherboards have just 2x2 [144 watt]
| | | | and have a tab for the latch on the
\_/ --- PSU end to attach to. The right-hand
___ ___ one above would not insert unless you
| | | | had an enthusiast 2x4 on the motherboard
| | | | with it's (approximate) 288W rating
--- \_/

HTH,
Paul


Thanks again Paul,

I don't have any more HDDs just SATA SSSDs. I ran the [email protected] app for
several days. the GPU monitor app said it reached 71 C. My CPU temperature
app never went above 50 C.

I will study this new information at length.

For now I have a new question. The shop that took the old 400W Dynex PSU
will likely refurbish it. I suggested that the capacitors should to be
renewed. In my MCP73VE motherboard there are many electrolytic parallel
capacitors. C=C1+C2+ ... +Cn etc. So maybe voltage ripple also comes from
the motherboard. It was new in 2008, which leads me to consider I may need a
new MOBO that will allow me to use my LGA775 Q9650 CPU and my 8GB of DDR2
RAM. Where there is a need, a market will follow.

I found this on eBay, at

https://www.ebay.ca/itm/P45-Motherbo...N R:rk:1:pf:0

P45 Motherboard Intel LGA 775 4*SATA III USB 2.0 support DDR2 4*8GB 1600Mhz
M2O6

With four DDR2 RAM slots it supports up to 32GB memory. I can use my Q9650
CPU (TDI 95W). I can use SATA III SSDs. It has USB 2.0, fine by me. But I'm
not sure of PCI or PCIe slots. He

https://www.ascendtech.us/mmASC/Images/SAK09-01.jpg

You can see an image of my old MCP73VE MOBO. It has 2 PCI slots. At the end
I have a phone/modem/fax board. Maybe I don't need it. There are two PCIe
slots one for 1X lanes and one I use for a 16X lane GPU board. In the future
I might use the 1X lane PCIe, as I have in the past. The GPU board over laps
one PCI slaot which I cannot use.

Do you think this would be a good buy?

Thanks.



--- news://freenews.netfront.net/ - complaints: ---
  #8  
Old February 25th 19, 05:01 AM posted to alt.comp.hardware
Paul[_26_]
external usenet poster
 
Posts: 958
Default What is the potential value of a used 400W ATX power suppy.

Norm X wrote:
[snippage]

Thanks Paul. The link to article you gave was useful. A nice man at a
repair shop gave me a short Molex to six pin GPU power adapter cable. I
gave him RAM I could not sell. I was confused a bit by an 8 pin connector
that could be split into two identical four pin connectors on the new
Amazon Coolmax PSU. I left the old Dynex PSU with the shop for
refurbishing. That may have been premature. I used scotch tape to
identify all the power connectors I used. The wire colors tell what is
correct. Either I get a call from the shop to tell me all is A OK, or I
can study the article you gave to satisfy my concern. I don't want to
power up unless everything is electrically correct.

If you use the short Molex to six pin GPU, note that the Molex connector
has enough ampacity to do the job, but then there's nothing left over
for hard drives. For example, doing this would be marginal, from the
HDD-requirements point of view. The GPU on the video card will likely
tolerate the tolerances on the 12V rail if done like this.

PSU
|
+--- HDD 1.5A
|
+--- HDD 1.5A
|
|
+--- adapter --- PCIe 12V @ 6A for 75W video card

What can happen if you do that, is the HDD may "spin-down" in
mid-session, because the voltage on the cable drops to around 11V
instead of 12V. The HDD is doing an "emergency shutdown", as it thinks
the PSU is about to turn off the power.

If using the adapter, you might do this. Now, if the cable voltage
drops to 11V because of ohms law, the video card won't shut off.

PSU
|
+---
|
+---
|
|
+--- adapter --- PCIe 12V @ 6A for 75W video card

Some of those adapters, come with two Molex. And they're intended
to be used like this. You connect each molex to a different chain,
in an attempt to spread the load, so the wires from the PSU work in
parallel and the voltage drop is slightly less.

PSU ---------------+
| |
+--- ---+
| |
+--- ---+
| |
| |
+---X X---+
\ /
+--+--+
|
PCIe 2x3 12V @ 6A

On a modern desktop PSU, the two wire looms in question
are likely off the same output, so you're not putting
outputs in parallel.

*******

The 2x4 that splits into two 2x2 is for ATX12V by the processor socket.

Traditionally, a Pentium 4 motherboard back in the day, had a 2x2
with two yellow wires and two black wires. The connector was keyed
by the shape of the nylon shroud around each pin. The motherboard
manual, on the good ones, would even show which pins where
+12V (yellow) and which were ground (black).

Later, there were several standards for server processor connectors
using 2x4 pins instead. Those don't split. And those are not
compatible with desktops either. Fortunately, you don't run into
those too often when buying desktop power supplies.

Enthusiast motherboards need more than 144W. Or 12V @ 12A on the 2x2
ATX12V. To solve that need, they combined more yellow and black wires.
By using a 2x4 with four yellow and four black, they get room
for 12V @ 24A to flow, or 288W. There are still some overclocking
experiments that draw more power than that (D-805 at 4GHz), but then
you'd probably be melting the motherboard when doing that anyway :-)

There is a 2x4 that splits into a 2x3 and a 2x1. That's PCI Express
and solving both 2x4 and 2x3 input requirements. One of the pins
involved there is a "sense" pin rather than a "current flow" pin,
and tells the video card a proper 2x4 PCIe power was plugged in.

You should have been able to see those on Playtool.

This is the ATX12V that splits in two pieces for usage with
legacy motherboards (near the CPU socket).

http://www.playtool.com/pages/psucon...plus4index.jpg

Whereas this is the PCI Express that does 2x3 or 2x4 PCIe power.

http://www.playtool.com/pages/psucon...plus2index.jpg

The shroud on the connector, is intended to prevent inappropriate
combinations. On the ATX12V that splits in half, one half has
the "right" shape for the 2x2 on an old motherboard. The second
half is the extension portion, and is the "wrong" shape to fit
a 2x2 on its own. This is purely arbitrary - what matters is
that no yellow wires on the PSU end, touch pins intended for ground,
and that causes a short and causes the PSU to shut off (if you're lucky).

This is a picture I drew previously. The drawing shows the shapes
in the plastic ends of the connectors involved for ATX12V.

ATX12V 4/8

TTTTTT TTTTTT End view of connector pair
___ ___ ___ ___ showing shapes which help
| | | | | | | | control mating only one way.
| | | | | | | |
\_/ --- \_/ \_/ You will be using the *left*
connector in pic.
___ ___ ___ ___ The right connector is used if
| | | | | | | | the motherboard had a 2x4 and room
| | | | | | | | for all eight pins.
--- \_/ \_/ \_/
TTTTTT is the tab which latches to
|| a feature on the side of the
connector
\||/ on the motherboard and provides a
\/ visual cue on how to do it.
___ ___
| | | | Normal motherboards have just 2x2 [144 watt]
| | | | and have a tab for the latch on the
\_/ --- PSU end to attach to. The right-hand
___ ___ one above would not insert unless you
| | | | had an enthusiast 2x4 on the motherboard
| | | | with it's (approximate) 288W rating
--- \_/

HTH,
Paul


Thanks again Paul,

I don't have any more HDDs just SATA SSSDs. I ran the [email protected] app for
several days. the GPU monitor app said it reached 71 C. My CPU temperature
app never went above 50 C.

I will study this new information at length.

For now I have a new question. The shop that took the old 400W Dynex PSU
will likely refurbish it. I suggested that the capacitors should to be
renewed. In my MCP73VE motherboard there are many electrolytic parallel
capacitors. C=C1+C2+ ... +Cn etc. So maybe voltage ripple also comes from
the motherboard. It was new in 2008, which leads me to consider I may need a
new MOBO that will allow me to use my LGA775 Q9650 CPU and my 8GB of DDR2
RAM. Where there is a need, a market will follow.

I found this on eBay, at

https://www.ebay.ca/itm/P45-Motherbo...N R:rk:1:pf:0

P45 Motherboard Intel LGA 775 4*SATA III USB 2.0 support DDR2 4*8GB 1600Mhz
M2O6

With four DDR2 RAM slots it supports up to 32GB memory. I can use my Q9650
CPU (TDI 95W). I can use SATA III SSDs. It has USB 2.0, fine by me. But I'm
not sure of PCI or PCIe slots. He

https://www.ascendtech.us/mmASC/Images/SAK09-01.jpg

You can see an image of my old MCP73VE MOBO. It has 2 PCI slots. At the end
I have a phone/modem/fax board. Maybe I don't need it. There are two PCIe
slots one for 1X lanes and one I use for a 16X lane GPU board. In the future
I might use the 1X lane PCIe, as I have in the past. The GPU board over laps
one PCI slaot which I cannot use.

Do you think this would be a good buy?

Thanks.


I see a little creative mis-labeling has driven you into a frenzy :-)
These Ebay sellers are pros at this stuff. No, it's not SATA III.

The only legend on the board is P45G41 in one corner. There is
no manufacturer listed. It could be a legendary PcChips. It's
more likely to be a grey market Chinese motherboard.

Now, right away, we have to trust what is under the Northbridge
heatsink is actually a P45. Those chip labels are both chips from
the same era, the first being more valuable than the second.
The G41 is used on budget boards (perfect for sheering sheep in fact).

The P45 is described here.

https://en.wikipedia.org/wiki/Intel_P45

1333/1066/800 MT/s front-side bus (FSB),
most motherboard manufacturers claim support up to 1600 MT/s.

PCI Express Rev2.0, 1*16 or 2*8 500MB/sec per lane, video slot only
Dual-channel DDR2 memory
up to 16 GiB addressable memory;
officially up to DDR2-800,
most motherboard manufacturers claim support up to 1200 MHz
Dual-channel DDR3 memory
up to 8 GiB addressable memory;
officially up DDR3-1066 MHz,
most motherboard manufacturers claim support up to 1333 MHz
ICH10 / ICH10R southbridge (250MB/sec PCIe Rev1.1 x1 lanes hosting)
Supports 45 nm processors

https://ark.intel.com/content/www/us...3-mhz-fsb.html

Bus Speed 1333MHz FSB
TDP 95W

We look up the chips that could go with these solutions and
they're totally SATA II.

https://en.wikipedia.org/wiki/I/O_Controller_Hub

ICH10 Six SATA 3Gbit/s [SATA II] ports
in either legacy IDE or AHCI mode. Can support external eSATA
ICH10R (similar)

That board has four SATA ports off the four port block, equipped.
The two port block is not connected to anything.

A board with a VGA connector on the I/O plate, only makes sense
if a G41 Northbridge is being used (the G41 would have a GPU
inside the Northbridge). The G41 is also paired with ICH7
(only 4 SATA II ports). PDF page 26. A G41 supports one DIMM
per channel, two DIMMs per motherboard. If CS signals are split,
then four slots can be filled... with single-sided memory (no net
gain in max-memory). A double-sided DIMM would be "half used".

https://www.intel.com/content/dam/ww...-datasheet.pdf

The board has three phase power for the processor. I would need
to track down a comparable motherboard of that era, and see using
the CPU-Support chart, whether a three phase typically supported
95W processors, or was limited to 65W processors. This is another
reason why we need a company name and a web site, to verify details.
I expect it probably does work with a Q9650, but no matter how
much that motherboard costs, I want to know this in advance, and
not via "experiment" and "smoke test". You don't want to damage
a Q9650 on a dare.

I know it's tempting, but it's only SATA II. If they'd put any other
kind of labeling on the motherboard but "P45G41", I might have even
fallen for it. But that's an immediate warning sign - "sheep shearing ahead".
Imagine how ****ed you'd be, if the DIMM slots were actually wired
so they only accessed one side of your double sided DIMMs.

The max memory is 16GB, as maybe 4x4GB. That's for DDR2. For
DDR3, the limit is 8GB total. The chip density support is listed
in the datasheet.

"Supports 512-Mb, 1-Gb, 2-Gb DDR2 and
512-Mb, 1-Gb DDR3 DRAM technologies
for x8 and x16 chip types."

The DDR3 stick with 16 chips, would be 2GB total on a stick.
Four of those sticks gives 8GB DDR3 total. You don't own
any DDR3 now, so this is not an issue for you, whereas
reusing your purchased DDR2 is the issue. I got myself
into the same situation, when buying the motherboard I'm
typing this on.

The first SATA III ports were on P67 PCH. And PCH means
there is no Northbridge, only a Southbridge. This is the
era where memory is hosted by an interface on the CPU itself.
The P67 (being 2 SATA III and 4 SATA II) was a disaster and
was recalled... because some transistors were put in upside-down
in the SATA III PHY. The boards had to be recalled, and the PCH
replaced with a different silicon rev. As it was suspected the
SATA III ports would eventually blow out. That's how Intel
entered the "SATA III era", with a "bang".

In the case of the P45/ICH10, the memory is hosted by the
P45, since an LGA775 doesn't have the pins for dual channel
memory right on the CPU. On the LGA1156, there are enough
signals to put memory on the CPU. An LGA775 will only work
with a limited set of chipsets, and would need a NB-SB
pair. The NB having the memory DIMM interfaces on it.

If you want SATA III, you can use a plugin card... which
will cost as much as the motherboard you're angling for.
You have to be careful when buying those - there is a
Marvell SATA III early chip, that only did 300MB/sec
instead of full SATA III. You should in that case, read
reviews and verify the card works good. You could
also benefit from a PCIe x4 slot for the card, as the
chipset you've got is PCIe Rev2 on video slots, and
PCIe Rev1 on SB-hosted PCIe lanes. My X48 has two PCIe x16
slots of the Rev2 variety, and this limits my SATA III
and USB3 speeds. To counter that, I bought a USB3 Rev2 card
with x2 lanes, and when that's plugged into my X48
motherboard, it has 1GB/sec of slot bandwidth, leaving
plenty of room for full USB3 Rev1 500MB/sec action. (If
I ran it with a Rev2 device, again, there would be no headroom
for it and it would maybe run 700MB/sec instead of
1GB/sec.) In any case, if you were to buy an X48, one
video slot goes to the video card, and the second slot
is handy for "super fast toys" of various sorts.

So while the Q9650 is a nice processor (I wouldn't mind
owning one), the rest of the chipset part of it is
"plonkerific". The X48 makes me feel a bit better,
but it's nothing to brag about. It's still a bit
stinky for benchmarking. No SSDs on this machine... :-)
Not unless I plug in the Asmedia card (and on those,
you have to shop carefully to get the right chip
on the card - there is more sheep sheering involved
with the purchase of those cards too).

If you can live with SATA II, then "buy it".

Paul
  #9  
Old February 25th 19, 07:07 AM posted to alt.comp.hardware
Norm X[_2_]
external usenet poster
 
Posts: 85
Default What is the potential value of a used 400W ATX power suppy.

[snippage]

Thanks Paul. The link to article you gave was useful. A nice man at a
repair shop gave me a short Molex to six pin GPU power adapter cable. I
gave him RAM I could not sell. I was confused a bit by an 8 pin
connector that could be split into two identical four pin connectors on
the new Amazon Coolmax PSU. I left the old Dynex PSU with the shop for
refurbishing. That may have been premature. I used scotch tape to
identify all the power connectors I used. The wire colors tell what is
correct. Either I get a call from the shop to tell me all is A OK, or I
can study the article you gave to satisfy my concern. I don't want to
power up unless everything is electrically correct.
If you use the short Molex to six pin GPU, note that the Molex connector
has enough ampacity to do the job, but then there's nothing left over
for hard drives. For example, doing this would be marginal, from the
HDD-requirements point of view. The GPU on the video card will likely
tolerate the tolerances on the 12V rail if done like this.

PSU
|
+--- HDD 1.5A
|
+--- HDD 1.5A
|
|
+--- adapter --- PCIe 12V @ 6A for 75W video card

What can happen if you do that, is the HDD may "spin-down" in
mid-session, because the voltage on the cable drops to around 11V
instead of 12V. The HDD is doing an "emergency shutdown", as it thinks
the PSU is about to turn off the power.

If using the adapter, you might do this. Now, if the cable voltage
drops to 11V because of ohms law, the video card won't shut off.

PSU
|
+---
|
+---
|
|
+--- adapter --- PCIe 12V @ 6A for 75W video card

Some of those adapters, come with two Molex. And they're intended
to be used like this. You connect each molex to a different chain,
in an attempt to spread the load, so the wires from the PSU work in
parallel and the voltage drop is slightly less.

PSU ---------------+
| |
+--- ---+
| |
+--- ---+
| |
| |
+---X X---+
\ /
+--+--+
|
PCIe 2x3 12V @ 6A

On a modern desktop PSU, the two wire looms in question
are likely off the same output, so you're not putting
outputs in parallel.

*******

The 2x4 that splits into two 2x2 is for ATX12V by the processor socket.

Traditionally, a Pentium 4 motherboard back in the day, had a 2x2
with two yellow wires and two black wires. The connector was keyed
by the shape of the nylon shroud around each pin. The motherboard
manual, on the good ones, would even show which pins where
+12V (yellow) and which were ground (black).

Later, there were several standards for server processor connectors
using 2x4 pins instead. Those don't split. And those are not
compatible with desktops either. Fortunately, you don't run into
those too often when buying desktop power supplies.

Enthusiast motherboards need more than 144W. Or 12V @ 12A on the 2x2
ATX12V. To solve that need, they combined more yellow and black wires.
By using a 2x4 with four yellow and four black, they get room
for 12V @ 24A to flow, or 288W. There are still some overclocking
experiments that draw more power than that (D-805 at 4GHz), but then
you'd probably be melting the motherboard when doing that anyway :-)

There is a 2x4 that splits into a 2x3 and a 2x1. That's PCI Express
and solving both 2x4 and 2x3 input requirements. One of the pins
involved there is a "sense" pin rather than a "current flow" pin,
and tells the video card a proper 2x4 PCIe power was plugged in.

You should have been able to see those on Playtool.

This is the ATX12V that splits in two pieces for usage with
legacy motherboards (near the CPU socket).

http://www.playtool.com/pages/psucon...plus4index.jpg

Whereas this is the PCI Express that does 2x3 or 2x4 PCIe power.

http://www.playtool.com/pages/psucon...plus2index.jpg

The shroud on the connector, is intended to prevent inappropriate
combinations. On the ATX12V that splits in half, one half has
the "right" shape for the 2x2 on an old motherboard. The second
half is the extension portion, and is the "wrong" shape to fit
a 2x2 on its own. This is purely arbitrary - what matters is
that no yellow wires on the PSU end, touch pins intended for ground,
and that causes a short and causes the PSU to shut off (if you're
lucky).

This is a picture I drew previously. The drawing shows the shapes
in the plastic ends of the connectors involved for ATX12V.

ATX12V 4/8

TTTTTT TTTTTT End view of connector pair
___ ___ ___ ___ showing shapes which help
| | | | | | | | control mating only one way.
| | | | | | | |
\_/ --- \_/ \_/ You will be using the *left*
connector in pic.
___ ___ ___ ___ The right connector is used if
| | | | | | | | the motherboard had a 2x4 and room
| | | | | | | | for all eight pins.
--- \_/ \_/ \_/
TTTTTT is the tab which latches to
|| a feature on the side of the
connector
\||/ on the motherboard and provides a
\/ visual cue on how to do it.
___ ___
| | | | Normal motherboards have just 2x2 [144 watt]
| | | | and have a tab for the latch on the
\_/ --- PSU end to attach to. The right-hand
___ ___ one above would not insert unless you
| | | | had an enthusiast 2x4 on the motherboard
| | | | with it's (approximate) 288W rating
--- \_/

HTH,
Paul


Thanks again Paul,

I don't have any more HDDs just SATA SSSDs. I ran the [email protected] app
for several days. the GPU monitor app said it reached 71 C. My CPU
temperature app never went above 50 C.

I will study this new information at length.

For now I have a new question. The shop that took the old 400W Dynex PSU
will likely refurbish it. I suggested that the capacitors should to be
renewed. In my MCP73VE motherboard there are many electrolytic parallel
capacitors. C=C1+C2+ ... +Cn etc. So maybe voltage ripple also comes
from the motherboard. It was new in 2008, which leads me to consider I
may need a new MOBO that will allow me to use my LGA775 Q9650 CPU and my
8GB of DDR2 RAM. Where there is a need, a market will follow.

I found this on eBay, at

https://www.ebay.ca/itm/P45-Motherbo...N R:rk:1:pf:0

P45 Motherboard Intel LGA 775 4*SATA III USB 2.0 support DDR2 4*8GB
1600Mhz M2O6

With four DDR2 RAM slots it supports up to 32GB memory. I can use my
Q9650 CPU (TDI 95W). I can use SATA III SSDs. It has USB 2.0, fine by me.
But I'm not sure of PCI or PCIe slots. He

https://www.ascendtech.us/mmASC/Images/SAK09-01.jpg

You can see an image of my old MCP73VE MOBO. It has 2 PCI slots. At the
end I have a phone/modem/fax board. Maybe I don't need it. There are two
PCIe slots one for 1X lanes and one I use for a 16X lane GPU board. In
the future I might use the 1X lane PCIe, as I have in the past. The GPU
board over laps one PCI slaot which I cannot use.

Do you think this would be a good buy?

Thanks.


I see a little creative mis-labeling has driven you into a frenzy :-)
These Ebay sellers are pros at this stuff. No, it's not SATA III.

The only legend on the board is P45G41 in one corner. There is
no manufacturer listed. It could be a legendary PcChips. It's
more likely to be a grey market Chinese motherboard.

Now, right away, we have to trust what is under the Northbridge
heatsink is actually a P45. Those chip labels are both chips from
the same era, the first being more valuable than the second.
The G41 is used on budget boards (perfect for sheering sheep in fact).

The P45 is described here.

https://en.wikipedia.org/wiki/Intel_P45

1333/1066/800 MT/s front-side bus (FSB),
most motherboard manufacturers claim support up to 1600 MT/s.

PCI Express Rev2.0, 1*16 or 2*8 500MB/sec per lane, video slot only
Dual-channel DDR2 memory
up to 16 GiB addressable memory;
officially up to DDR2-800,
most motherboard manufacturers claim support up to 1200 MHz
Dual-channel DDR3 memory
up to 8 GiB addressable memory;
officially up DDR3-1066 MHz,
most motherboard manufacturers claim support up to 1333 MHz
ICH10 / ICH10R southbridge (250MB/sec PCIe Rev1.1 x1 lanes hosting)
Supports 45 nm processors

https://ark.intel.com/content/www/us...3-mhz-fsb.html

Bus Speed 1333MHz FSB
TDP 95W

We look up the chips that could go with these solutions and
they're totally SATA II.

https://en.wikipedia.org/wiki/I/O_Controller_Hub

ICH10 Six SATA 3Gbit/s [SATA II] ports
in either legacy IDE or AHCI mode. Can support external eSATA
ICH10R (similar)

That board has four SATA ports off the four port block, equipped.
The two port block is not connected to anything.

A board with a VGA connector on the I/O plate, only makes sense
if a G41 Northbridge is being used (the G41 would have a GPU
inside the Northbridge). The G41 is also paired with ICH7
(only 4 SATA II ports). PDF page 26. A G41 supports one DIMM
per channel, two DIMMs per motherboard. If CS signals are split,
then four slots can be filled... with single-sided memory (no net
gain in max-memory). A double-sided DIMM would be "half used".

https://www.intel.com/content/dam/ww...-datasheet.pdf

The board has three phase power for the processor. I would need
to track down a comparable motherboard of that era, and see using
the CPU-Support chart, whether a three phase typically supported
95W processors, or was limited to 65W processors. This is another
reason why we need a company name and a web site, to verify details.
I expect it probably does work with a Q9650, but no matter how
much that motherboard costs, I want to know this in advance, and
not via "experiment" and "smoke test". You don't want to damage
a Q9650 on a dare.

I know it's tempting, but it's only SATA II. If they'd put any other
kind of labeling on the motherboard but "P45G41", I might have even
fallen for it. But that's an immediate warning sign - "sheep shearing
ahead".
Imagine how ****ed you'd be, if the DIMM slots were actually wired
so they only accessed one side of your double sided DIMMs.

The max memory is 16GB, as maybe 4x4GB. That's for DDR2. For
DDR3, the limit is 8GB total. The chip density support is listed
in the datasheet.

"Supports 512-Mb, 1-Gb, 2-Gb DDR2 and
512-Mb, 1-Gb DDR3 DRAM technologies
for x8 and x16 chip types."

The DDR3 stick with 16 chips, would be 2GB total on a stick.
Four of those sticks gives 8GB DDR3 total. You don't own
any DDR3 now, so this is not an issue for you, whereas
reusing your purchased DDR2 is the issue. I got myself
into the same situation, when buying the motherboard I'm
typing this on.

The first SATA III ports were on P67 PCH. And PCH means
there is no Northbridge, only a Southbridge. This is the
era where memory is hosted by an interface on the CPU itself.
The P67 (being 2 SATA III and 4 SATA II) was a disaster and
was recalled... because some transistors were put in upside-down
in the SATA III PHY. The boards had to be recalled, and the PCH
replaced with a different silicon rev. As it was suspected the
SATA III ports would eventually blow out. That's how Intel
entered the "SATA III era", with a "bang".

In the case of the P45/ICH10, the memory is hosted by the
P45, since an LGA775 doesn't have the pins for dual channel
memory right on the CPU. On the LGA1156, there are enough
signals to put memory on the CPU. An LGA775 will only work
with a limited set of chipsets, and would need a NB-SB
pair. The NB having the memory DIMM interfaces on it.

If you want SATA III, you can use a plugin card... which
will cost as much as the motherboard you're angling for.
You have to be careful when buying those - there is a
Marvell SATA III early chip, that only did 300MB/sec
instead of full SATA III. You should in that case, read
reviews and verify the card works good. You could
also benefit from a PCIe x4 slot for the card, as the
chipset you've got is PCIe Rev2 on video slots, and
PCIe Rev1 on SB-hosted PCIe lanes. My X48 has two PCIe x16
slots of the Rev2 variety, and this limits my SATA III
and USB3 speeds. To counter that, I bought a USB3 Rev2 card
with x2 lanes, and when that's plugged into my X48
motherboard, it has 1GB/sec of slot bandwidth, leaving
plenty of room for full USB3 Rev1 500MB/sec action. (If
I ran it with a Rev2 device, again, there would be no headroom
for it and it would maybe run 700MB/sec instead of
1GB/sec.) In any case, if you were to buy an X48, one
video slot goes to the video card, and the second slot
is handy for "super fast toys" of various sorts.

So while the Q9650 is a nice processor (I wouldn't mind
owning one), the rest of the chipset part of it is
"plonkerific". The X48 makes me feel a bit better,
but it's nothing to brag about. It's still a bit
stinky for benchmarking. No SSDs on this machine... :-)
Not unless I plug in the Asmedia card (and on those,
you have to shop carefully to get the right chip
on the card - there is more sheep sheering involved
with the purchase of those cards too).

If you can live with SATA II, then "buy it".

Paul


Thanks for you professional opinion Paul. On the other hand, if my rig
becomes unstable, maybe I should have the shop put a scope on it. If the
electrolytic capacitors are bad. I could pay them to replace them. Their
labor is cheap but I should look into the price of new capacitors. This
image:

https://www.ascendtech.us/mmASC/Images/SAK09-01.jpg

shows capacitors all lined up in rows and could be desoldered and
resoldered.



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  #10  
Old February 25th 19, 09:34 AM posted to alt.comp.hardware
Paul[_26_]
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Posts: 958
Default What is the potential value of a used 400W ATX power suppy.

Norm X wrote:


Thanks for you professional opinion Paul. On the other hand, if my rig
becomes unstable, maybe I should have the shop put a scope on it. If the
electrolytic capacitors are bad. I could pay them to replace them. Their
labor is cheap but I should look into the price of new capacitors. This
image:

https://www.ascendtech.us/mmASC/Images/SAK09-01.jpg

shows capacitors all lined up in rows and could be desoldered and
resoldered.


In your picture, the caps next to the CPU are polymer caps and they
filter VCore (output).

The row of caps near to the ATX12V are input side filtering
on VCore. Those ones happen to be electrolytic.

The reason there are numerically so many caps, is ripple current.
Regular electrolytics have a relatively low ripple current
rating. By putting six caps in parallel, one sixth of the
current flows in each one.

When the cap has an AC voltage across it, and a reactance Xc,
an AC current flows. This current can be measured in amps. It's
quite a significant amount. It can make the capacitors get
warm. The hotter a cap gets, the shorter its life.

Now, Sanyo Oscons have a much higher ripple current rating.
You could, in principle, select a single Oscon and replace
the six other caps. But, we don't do that. If you have the
app note, it gives all the equations. You could plug in
the Oscon characteristics, and the equations would tell you
how to tune some of the other discretes. In other words, if
you put "too good" a capacitor in the circuit, it actually
throws the parametrics off and the circuit needs a slight
redesign.

So when changing caps, you continue to use as many caps
as were there before. And you use the same "class" of caps.
If it didn't have Oscons when you got it, you don't put
Oscons in it. You use the same flavor of caps as you found,
and then you don't have to redo all the math. And the
capacitance isn't critical. If the circuit had 1500uF caps,
you could use a 1200uF cap, or an 1800uF cap for all six.
It makes a slight difference to ripple amplitude and
closed loop stability.

Both the motherboard designer and the Vcore application note
writer, think alike. Neither is interested in Oscons. Both
know that the price "sweet spot", is with certain kinds of
"decent but ordinary" caps.

The caps have such predictable characteristics, you can tell
if someone is cheating purely by "volumetric considerations".
For example, when I see some caps on a motherboard, I head
over to a catalog and look for a replacement, and an E size
case has to be replaced with an F sized cap, it tells me the
original cap was inferior and the undersized nature of it
means it was probably under more stress than would be desired.
The larger cap I'd be called on to substitute, won't fit, because
the cap outlines are shoulder to shoulder, and if I buy that
F-sized cap, and put six next to one another, the end two
won't be insert-able into the board. (Some of the caps
will be leaning like fallen trees.)

You try not to leave a lot of lead length on them when installing
them. But I have seen people do recapping jobs where they're
forced to do less than optimal installations of them.

*******

It's hard to get those caps out. There are two hole styles.
At work, we had a "relaxed fit" hole for electrolytics, and
used a lead bender to "form" the legs so they wouldn't fall
out. The result of doing this, is when you need to do
maintenance on them later, you heat up the oversized holes and
the cap just "falls out". Great. Then you clean up with
a solder sucker and solder wick and head off and look for
the replacement to insert.

The other kind of situation is more common. The other place
I worked, used "straight" capacitor legs and "interference fit"
holes. These are a bitch. I used a vacuum desoldering station,
and spent around two hours one day, trying to nudge those out.
The thing is, the solder is good and hot and is ready to behave.
But because the cap leg is "jammed" into the hole, even pulling
with a pair of pliers isn't working. And if you pull too hard ?
The entire fillet comes out, and you're ****ed.

So who ever is doing your re-cap job, they have my respect.
It's hard work to rework boards like that. And it so happens
the computer motherboards are inferior quality.

We had a board shop apply a series of optional processes,
that made our board blanks "bulletproof". You could rest a
soldering iron on the laminate, and the foil wouldn't lift.
Whereas if you put an iron on an Asus motherboard for 30 seconds,
a pad could end up stuck to the tip of your iron. (Typically
happens to pads with no copper track connected to them.) Not
only is it hard work, but you're also working with motherboards
that don't take kindly to abuse of any sort. You could
easily ruin the board.

So if the caps are interference fit, bad things are going
to happen, and the dude at the soldering station is going
to be putting coin in his swear jar. I had all the right
equipment for the job, but the stuff just wasn't being cooperative,
and I would not look forward to doing that a second time.

Even if you apply ChipQuik to the joints before attempting
removal, there is still the problem that the legs were
jammed in there. A "relaxed fit hole", on the other hand,
just about any one could do one of those.

Sometimes the fit is so tight, the auto-insertion machine
"crumples" the cap when fitting it the first time. And they're
using this interference fit idea, so the caps can't move
as they go through the soldering process.

Paul
 




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