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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, 01:55 AM posted to alt.comp.hardware
Norm X[_2_]
external usenet poster
 
Posts: 83
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, 11:42 AM posted to alt.comp.hardware
Paul[_26_]
external usenet poster
 
Posts: 939
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, 04:40 AM posted to alt.comp.hardware
Norm X[_2_]
external usenet poster
 
Posts: 83
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, 05:27 AM posted to alt.comp.hardware
Paul[_26_]
external usenet poster
 
Posts: 939
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 Yesterday, 08:04 AM posted to alt.comp.hardware
Norm X[_2_]
external usenet poster
 
Posts: 83
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 Yesterday, 09:07 AM posted to alt.comp.hardware
Paul[_26_]
external usenet poster
 
Posts: 939
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
 




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