"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.



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