Can ATX PSU blow the mainboard?

[Johny B Good]

====snip====

Maybe I should also get a spare fuse. If the fuse markings are
indistinct, what's the typical fuse value for a 250W ATX PSU? (The
actual PSU model is FSP250-60GTV.)

I wouldn't worry about replacing the fuse. It's soldered in because
the most likely reason for _its_ failure would be a component failure
in the HT module (rectifier, HT smoothing capacitor(s) or switching
transistor(s)) which would require the use of a soldering iron anyway
in the event of any attempts at repairing the fault.

The safety fuse (for that is what it is) is fitted simply to prevent
catastrophic HT component failure becoming a fire hazard. It's not
there to protect components in the HT module.

 

[Jason]

====snip====


I wouldn't worry about replacing the fuse. It's soldered in because
the most likely reason for _its_ failure would be a component failure
in the HT module (rectifier, HT smoothing capacitor(s) or switching
transistor(s)) which would require the use of a soldering iron anyway
in the event of any attempts at repairing the fault.

The safety fuse (for that is what it is) is fitted simply to prevent
catastrophic HT component failure becoming a fire hazard. It's not
there to protect components in the HT module.

Hello Johny. You were right about the fan needing a bit of lube.

This PC was manufactured in 2001 and has been used almost every day since
then for several hours, so I thought the fan bearings must be worn by now.
However your lube idea works. So far.

It must a better quality fan than I realised. It's an 80mm fan by Yate
Loon (model D80SH-12). Is that a good fan?

 

[Johny B Good]

Hello Johny. You were right about the fan needing a bit of lube.

The bearings are often sintered bronze which, if properly lubed, can
outlast the more complex ball race bearings. Sometimes the
manufacturer fails to impregnate the porous sintered bearings with
enough oil causing them to prematurely gum up and chatter. If caught
in time, that extra drop of oil can make all the difference and extend
the life considerably.

This PC was manufactured in 2001 and has been used almost every day since
then for several hours, so I thought the fan bearings must be worn by now.
However your lube idea works. So far.

That's the big question mark, just how long is "so far"? It could
last for anywhere from a few months to several years depending on how
long it had been allowed to run 'dry' before the problem was fixed.

However, I'd say that PSU has lasted well to still be functioning
after some 12 years of daily use. My guess on the hours per day would
be something like just 2 or 3.

I've noticed that most ATX PSUs include a MTBF figure in their specs,
ranging from a poxy 10,000 hours for a cheap commodity unit right up
to 100,000 hours for the more pricey quality brands. 10,000 hours
represents around 3 1/2 years at 8 hours per day on a 6 day week which
is why I suspect the 2 or 3 hours a day usage in your case. The MTBF
is usually based on the quality of the capacitors used rather than on
the endurance of the fan.

It must a better quality fan than I realised. It's an 80mm fan by Yate
Loon (model D80SH-12). Is that a good fan?

I'm afraid I cannot say one way or the other. You could always try a
google search to get a better idea (and ditto for the PSU make and
model - although at 12 years old it's most likely to be only of
historical interest by now but you might find some anecdotal evidence
as to its quality).

Since you're, quite rightly, concerned about the reliability of that
PSU, I suggest you buy a suitably rated ATX PSU (either a cheap
commodity unit to keep as a spare or else invest in a better quality
one as a replacement - keeping the not yet failed original as a spare
for 'just in case'. I think it's reasonable to assume that your
existing unit is 'On Borrowed Time'.

 

[westom1]

I may be mistaken but ISTR there's a possibility of a voltage surge when
the PSU goes.

If the PSU meets ATX specs and power supply standards long before the IBMPC existed, then no PSU failure damages any computer parts.

However, a power supply manufacturer is not required to meet ATX and other standards. The computer assembler is required to meet those standards. So some PSU manufacturers 'forget' to include many functions required to meet ATX and other standards.

They know many 'assume' it must be good because it boots the computer. Nonsense. The PSU can be defective or can be missing essential ATX functions. And will still boot a computer. But when a PSU part fails, many required functions inside every ATX compatible supply makes computer part damage all but impossible.

Damage from a particular supply indicates a supply marketed to computer assemblers without even basic electrical knowledge.

Heat is not the typical reason for PSU failure. All computer parts should be perfectly happy even in a 100 degree F room. Manufacturing defects are the most common reason for PSU failures. We all saw defectively manufactured electrolytic capacitors fail years later due to counterfeit electrolyte. Another example of reasons for most PSU failures.

 

[Flasherly]

They know many 'assume'

it must be good because it boots the computer. Nonsense. The PSU can
be defective or can be missing essential ATX functions. And will
still boot a computer. But when a PSU part fails, many required
functions inside every ATX compatible supply makes computer part
damage all but impossible.

 

[westom1]

Nonsense. Run a MB with failing capacitors. Besides a diet of PS
units, it'll also eventually take out drives.

Bad capacitors do not cause destructive voltages. If you knew otherwise,then you posted specifications and numbers to say so. You don't for one good reason. That damage is not possible. And spec numbers contradict thosedenials.

ATX specifications define protection ... with numbers ... that say why aPSU (properly designed) will not harm drives. If you know otherwise, thendefine the disk drive part put at risk. And provide numbers from datasheets that define why that part is damaged. Good luck.

PSUs contains circuits to prevent electronics damage long before the IBM PC even existed. Long an industry standard.

 

[Flasherly]

On Sat, 9 Nov 2013 18:31:53 -0800 (PST), (e-mail address removed) wrote:

Bad capacitors do not cause destructive voltages. If you knew
otherwise, then you posted specifications and numbers to say so. You
don't for one good reason. That damage is not possible. And spec
numbers contradict those denials.

ATX specifications define protection ... with numbers ... that say
why a PSU (properly designed) will not harm drives. If you know
otherwise, then define the disk drive part put at risk. And provide
numbers from datasheets that define why that part is damaged. Good
luck.

PSUs contains circuits to prevent electronics damage long before the
IBM PC even existed. Long an industry standard.

--
That's certainly within reason, as well supportive of definable
standards within electrical laws governing them. However, you've went
too far to impinge localized damage is neither within reason or
demonstrably evident. What you need to do is get off my butt with
your numbers and publications, long enough to where I can supply good
reason for specifically why I'm citing a MB as catastrophic source for
PS unit failure(s);- yes, I went thru several -- one being among the
best made, which it literally smoked -- before ditching that
particular MB.

Expensive as in and for oh-wells.

OK. To be fair to you, I don't know and shouldn't have claimed with
certitude -- only -- that capacitors on the MB are the culprits. When
the MB in question did, however, eat PS units on a regular basis.

.... Probably went through three or four PS units over its course of
usage - a long one, with the problem surfacing, I'd estimate, at a
halfway point of its life. Aberant hard & software behavior had also
surfaced, also in conjunction, when a supplementary diet of power
supplies were provided, on average for a yearly basis, within some
subsequent, general improvement of a condition loosely classifable
for "coaxing it along."

As mentioned, I put in an industrial, server-grade PS on my last-ditch
attempt to revive the MB, whereupon it literally smoked it.

OK. So it wasn't capacitors, which just fine if you say so.

.... As I can't say, conversely, I'm well enough versed, otherwise, in
testing micro-electronics. I'd be, more correctly to back up and
revise my statement, "grasping" at a known period when several MBs
manufacturers equipped their products with bad capacitors - within the
same timeframe incident to when I purchased that particular ASUS MB.
As for the general hypothesis, then, I advanced: PSupply units are
impervious, tell me again you believe it. A good joke is never out of
place.

 

[westom1]

OK. So it wasn't capacitors, which just fine if you say so.

If capacitors cause damage, then included is how capacitors cause damage toother electronics. In generations of design and support, I have never seen such damage. However, if you know how a capacitor can cause that damage,then please explain it.

Many see an incandescent bulb flash and burn out with power on. That proves power cycling damages light bulbs? Not for one minute. Conclusions based only in observation are classic junk science. To have a fact means alsolearning underlying principles and numbers. What damages light bulbs? Facts are well published even with industry standard equations that define failure. Bulbs fail due to hours of operation and voltage (temperature). Power cycling causing damage only when observation contradicts well proven science.

Same with a motherboard causing PSU failure. Long before PCs existed, all power supply outputs could be shorted together - without damage. Intel'sATX standards even defined how thick that shorting wire should be. A PSU damaged by the load (ie motherboard or shorting wire) was probably designed(or constructed) defectively.

In a market dominated by computer assemblers, then manufacturers can dumpinferior PSUs into the market. Many would blame the load (ie motherboard), mythical surges, or 'dirty' electricity rather than a PSU that was defective when manufactured. Blame based only on observation and speculation.

Most failures are due to manufacturing defects. To say more requires identifying a specific reason for each failure. I have done that often to sometimes discover PSUs missing essential functions. Because PSUs are often marketed to people who do not even routinely demand spec sheets with each supply. No spec sheets mean it need not even meet national safety requirements, FCC regulations, or ATX standards. No spec numbers is a first symptom of missing essential functions. It may even self destruct on Intel's 'short all outputs together' test.

What caused a failure? A specific part in conjunction with how PSUs workis required for any valid conclusion. Most every PSU analyzed (by making it functional) failed due to manufacturing defects.

Spec sheets should include spec numbers that say it cannot damage the disk drive or motherboard. Required protection that might be missing IF written specifications do not say it exists. Conclusions only from observation (also called wild speculation) do not say why failures happen. If the PSU is properly designed, then it does not damage disk drives. And the load (motherboard or even a short circuit) does not damage the PSU.

Failing capacitors do not damage electronics. But it does explain strange and intermittent problems that some even blame on a virus (software) or surges. Speculation based only in observation is classic junk science. Theload does not damage a properly designed PSU - as was standard long beforePCs existed.

 

[Flasherly]

On Sun, 10 Nov 2013 08:53:41 -0800 (PST), (e-mail address removed) wrote:

What caused a failure? A specific part in conjunction with how PSUs
work is required for any valid conclusion. Most every PSU analyzed
(by making it functional) failed due to manufacturing defects.

Spec sheets should include spec numbers that say it cannot damage
the disk drive or motherboard. Required protection that might be
missing IF written specifications do not say it exists. Conclusions
only from observation (also called wild speculation) do not say why
failures happen. If the PSU is properly designed, then it does not
damage disk drives. And the load (motherboard or even a short
circuit) does not damage the PSU.

Failing capacitors do not damage electronics. But it does explain
strange and intermittent problems that some even blame on a virus
(software) or surges. Speculation based only in observation is
classic junk science. The load does not damage a properly designed
PSU - as was standard long before PCs existed.

--
Conclusions from observation are also called empiricism, (expounded by
John Locke, George Berkeley, and David Hume);- ipso facto, because the
timeframe is archaic, however, isn't conclusive that the methodology
is, in fact, quackery.

No, these are not garbage-assembled PSUs I'm referring to. Deferring
further back to my first PS problem, I'd date back to roughly around
when standard computer operations were performed on an Intel 8088
4.47Mhz MPU, on a MB I'd replaced the Intel for a NEC V20 at 8Mhz.
(I'd also equipped it with 3Meg of RAM via an ISA RAMPAGE board for
swapping programs concurrently in and out of memory.)

With a Q80 tape drive unit, I ran into a problem with the tapes
experiencing corruption. Exasperated, I'd replaced, "swapped out" the
entire computer, on my own assembly and build from parts ordered,
still, without any luck to have correctly addressed the Q80 tape
problem. Whereupon a thought occurred the PSU was the culprit.

I then wrapped the PS with tin-foil, ostensibly, to determine I'd
stopped spurious RF propagation from (somehow) entering the tape
during backup processes. Nevertheless, the problem was solved by a
tinfoil-wrapped PSU. Based entirely upon thought and observation.
Incidental to some commitment to the PC industry for reserves of
expensive money, (of course destined to FED Chairman Greenspan's
committal to shutting down an overheated PC industry), in a modular
approach to the homeowner's perspective to a build.

Going forward in time to the present PS units, we're really much
better off with what's being economically offered viz-a-viz quality
among components manufactured. And I was right in the thick of it,
dollar cost averaging my present computer builds with gorgeously
reviewed PS units -- well, a tier up in reception from assembler's
perspectives, as opposed to ready-made computers -- usually from a
rebate on severely discounting the PSUs I fed that particular ASUS MB.

But, I'm entirely with you. Damned and not equipped, from time and
involvement well enough to qualify me for a PC historian, if not
numbering among the ranks of its garage-building pioneers, to now come
up with an offer and better explanation for why that MB broke-down and
consumed a steady diet of PSUs.

Don't get me wrong, friend. I'm good. Just not that good.

 

[westom1]

I then wrapped the PS with tin-foil, ostensibly, to determine I'd
stopped spurious RF propagation from (somehow) entering the tape
during backup processes. Nevertheless, the problem was solved by a
tinfoil-wrapped PSU.

If RF radiation caused a tape drive problem, that tape drive was defectiveby design. If a PSU was radiating that much RF, then that PSU was defective by design.

Today's power supplies are not necessarily better than what powered 8080 based computers (before PCs). For example, the original IBM PC featured a 'Power Good' signal so that corrupting execution would not happen with defective power.

I recently bought a used supply. Opened it. Discovered missing and required filters. Holes for those part existed. Jumpers were installed so thatthe manufacturer could cut costs by 'forgetting' required parts. Then I noticed other missing circuits. So I continued the investigation.

Power Good signal for this recently built computer did not monitor voltages. 12 and 3.3 volts could be missing. Five volts could have been only three volts. And that Power Good signal would report all voltages OK. A major fubar existed because so many computer techs do not even know basic PSU functions.

This 'defective by design' supply - promoted as an ATX supply - could explain why power loss corrupts data and other problems. An example of PSUs marketed to computer assemblers who 'feel' they are computer savvy rather than learn what a PSU does.

How many 'know' unexpected power loss is destructive? Many saw a sudden power loss create other failures. Then assume power loss is destructive - using observation or hearsay as fact. Unexpected power loss never causes damage to properly designed equipment - not even disk drives. But many justknow because they saw damage. Or learned from hearsay. Assumed a conclusion based upon observation.

If enclosing a PSU in tin foil eliminates failure, then a 'symptom' is defined; not a solution. First find symptoms - especially those that are reproducible. Solutions come later after identifying a reason for that symptom. A defectively designed PSU? A defectively manufactured tape drive? Tin foil did not cure a problem; only cured a symptom. Since a PSU must not output major RF. And tape drives must make RF radiation irrelevant.

Our current PSU standards are roundly superior to what existed before theIBM PC. And still many consumers buy PSUs that are inferior to old technology. A computer assembler (not the PSU manufacturer) is responsible for what is inside a computer's PSU. Many computer assemblers do not even know that.

Properly designed PSUs are not damaged by the load. An overheated PSU must not cause computer damage. And would not cause a destructive surge. Early posters noted this. And also recommended a tool that every informed computer troubleshooter uses - a meter. So that problems are identified (with numbers) before fixing anything.

A PSU damaged by its motherboard would be as defective as that PSU with abad Power Good signal.

 

[Chris S.]

I then wrapped the PS with tin-foil, ostensibly, to determine I'd
stopped spurious RF propagation from (somehow) entering the tape
during backup processes. Nevertheless, the problem was solved by a
tinfoil-wrapped PSU.

If RF radiation caused a tape drive problem, that tape drive was defective
by design. If a PSU was radiating that much RF, then that PSU was defective
by design.

Today's power supplies are not necessarily better than what powered 8080
based computers (before PCs). For example, the original IBM PC featured a
'Power Good' signal so that corrupting execution would not happen with
defective power.

I recently bought a used supply. Opened it. Discovered missing and
required filters. Holes for those part existed. Jumpers were installed so
that the manufacturer could cut costs by 'forgetting' required parts. Then
I noticed other missing circuits. So I continued the investigation.

Power Good signal for this recently built computer did not monitor
voltages. 12 and 3.3 volts could be missing. Five volts could have been
only three volts. And that Power Good signal would report all voltages OK.
A major fubar existed because so many computer techs do not even know basic
PSU functions.

This 'defective by design' supply - promoted as an ATX supply - could
explain why power loss corrupts data and other problems. An example of PSUs
marketed to computer assemblers who 'feel' they are computer savvy rather
than learn what a PSU does.

How many 'know' unexpected power loss is destructive? Many saw a sudden
power loss create other failures. Then assume power loss is destructive -
using observation or hearsay as fact. Unexpected power loss never causes
damage to properly designed equipment - not even disk drives. But many just
know because they saw damage. Or learned from hearsay. Assumed a conclusion
based upon observation.

If enclosing a PSU in tin foil eliminates failure, then a 'symptom' is
defined; not a solution. First find symptoms - especially those that are
reproducible. Solutions come later after identifying a reason for that
symptom. A defectively designed PSU? A defectively manufactured tape
drive? Tin foil did not cure a problem; only cured a symptom. Since a PSU
must not output major RF. And tape drives must make RF radiation
irrelevant.

Our current PSU standards are roundly superior to what existed before the
IBM PC. And still many consumers buy PSUs that are inferior to old
technology. A computer assembler (not the PSU manufacturer) is responsible
for what is inside a computer's PSU. Many computer assemblers do not even
know that.

Properly designed PSUs are not damaged by the load. An overheated PSU
must not cause computer damage. And would not cause a destructive surge.
Early posters noted this. And also recommended a tool that every informed
computer troubleshooter uses - a meter. So that problems are identified
(with numbers) before fixing anything.

A PSU damaged by its motherboard would be as defective as that PSU with a
bad Power Good signal.

+ A lot. Well said
Chris

 

[Flasherly]

If RF radiation caused a tape drive problem, that tape drive was
defective by design. If a PSU was radiating that much RF, then that
PSU was defective by design.Today's power supplies are not necessarily better than what powered
8080 based computers (before PCs). For example, the original IBM PC
featured a 'Power Good' signal so that corrupting execution would not
happen with defective power.I recently bought a used supply. Opened it. Discovered missing and
required filters. Holes for those part existed. Jumpers were
installed so that the manufacturer could cut costs by 'forgetting'
required parts. Then I noticed other missing circuits. So I
continued the investigation.Power Good signal for this recently built computer did not monitor
voltages. 12 and 3.3 volts could be missing. Five volts could have
been only three volts. And that Power Good signal would report all
voltages OK. A major fubar existed because so many computer techs do
not even know basic PSU functions.This 'defective by design' supply - promoted as an ATX supply -
could explain why power loss corrupts data and other problems. An
example of PSUs marketed to computer assemblers who 'feel' they are
computer savvy rather than learn what a PSU does.How many 'know' unexpected power loss is destructive? Many saw a
sudden power loss create other failures. Then assume power loss is
destructive - using observation or hearsay as fact. Unexpected power
loss never causes damage to properly designed equipment - not even
disk drives. But many just know because they saw damage. Or learned
from hearsay. Assumed a conclusion based upon observation.If enclosing a PSU in tin foil eliminates failure, then a 'symptom'
is defined; not a solution. First find symptoms - especially those
that are reproducible. Solutions come later after identifying a
reason for that symptom. A defectively designed PSU? A defectively
manufactured tape drive? Tin foil did not cure a problem; only cured
a symptom. Since a PSU must not output major RF. And tape drives
must make RF radiation irrelevant.Our current PSU standards are roundly superior to what existed
before the IBM PC. And still many consumers buy PSUs that are inferior
to old technology. A computer assembler (not the PSU manufacturer) is
responsible for what is inside a computer's PSU. Many computer
assemblers do not even know that.Properly designed PSUs are not damaged by the load. An overheated
PSU must not cause computer damage. And would not cause a destructive
surge. Early posters noted this. And also recommended a tool that
every informed computer troubleshooter uses - a meter. So that
problems are identified (with numbers) before fixing anything.A PSU damaged by its motherboard would be as defective as that PSU
with a bad Power Good signal.

--
The RF PS problem would eventually have been correctly rectified by a
non-defective PS unit, I ordered, when I observed the problem
continued to exist with a mis-diagnosed, entire inner-computer
replacement, upon simply covering the faults of the same PS with
tinfoil.

Lesson 1: Quality PSUs are important and good to own. I've went
through years with several budget units and found, on average, their
life span sub par to quality units.

The opposite, however, quality PSUs continuing to fault over a course
of years for a MB to become suspect was new to me. True, an onus is
ultimately the responsibility of the assembler to open the PSU,
inspect and monitor it for proper operation. Paying a little extra
for reputability on the part of a jobber, middleman supplier of
computer components to stock known and reputable parts is within
pragmatic means. (L1-b: Dollar Cost Averaging doesn't work without a
competitive basis equal to a standard of assured quality. Which is
where I go now to buy a named, researched PSU, tested for
certifiable.)

Purchased over-rated and beyond a PC draw and associated peripheral
capacity I'd actually impressed upon the PSU might also be within an
increasing trend of failures I was experiencing. Always with a fresh
PSU augmenting a positiveness overall to PC behavior, subsequent to a
deteriorating timeframe, between PSU changes, of continued aberrant
links to the MB hardware. The most blatant offender would be a call
to a popular CD/DVD burning software, NERO, whereupon the system would
crash and reboot. Similar proneness was evident from software to
system suspension to attempt to read optical media. (I would say I
employed over a variety of as much as six optical drives.)

Why PSUs we drawn down in time to a inservient states operability,
upon that particular MB, a new PSU would somehow regenerate, only lead
me strongly to suspect the MB for a known Eater of (perfectly good)
PSUs.

Qualifiedly, of course, within a whole world of darkness surrounding
actual electrical physics and principles of their application, I
admittedly know less about, to reason or concretely support my
dumbfounded accusations. But, to stand there, long last, and watch a
FORTRON server-grade PSU (I somewhat cherished, literally, as heavy as
a brick) give it up in a whiff of smoke. . .doesn't even begin to
explain the resentment I felt for that ASUS MB. (Nor myself for why I
pushed it so far and long as I did. I'm now running Gigabyte
solid-state capacitor-equipped MBs. FWIW, corporate Gigabyte released,
around the same timeframe of my ASUS, a damning accusation against
ASUS for knowingly using bad capacitors.)

 

[Guest]

Bad capacitors do not cause destructive voltages.

They don't cause them, but they can allow them by not filtering out
voltage spikes from switching mode supplies or even spikes generated by
sudden changes in load when chips change state, sometimes causing even
excessive negative voltage spikes. All this was covered by Intel's
application notes for even when they were still producing DRAM chips.

 

[Flasherly]

All this was covered by Intel's
application notes for even when they were still producing DRAM chips.

Blown plenty of those, back in the day - 9 chips in row, 8 legs to a
socketed chip -- 4 or 8 banked rows provided on a MB. Dare breathe on
them on an inauspicious day, and the gods would decree that enough to
blow off one or two chips, loosing a bank or two of memory. Yep -
baggies of spare chips for propitiating bored Gods of electron valence
with their version of 52-pickup.

 

[westom1]

They don't cause them, but they can allow them by not filtering out
voltage spikes from switching mode supplies or even spikes generated by
sudden changes in load when chips change state, sometimes causing even
excessive negative voltage spikes.

All those situations are made virtually impossible by how a PSU is designed. For example, a diode exists between different voltages so that one voltage cannot go negative in relation to another. But again, when buying PSUs that do not even provide spec numbers, then a computer assembler is 100% responsible for any resulting damage by that defective supply. An application note defines problems that must be made irrelevant by the design.

Even spikes generated by switching circuits are quashed by another and required circuit that must exist. ATX standards even define voltages that each protection circuit must trigger. And again, when is that required function missing. Only a computer assembler is responsible for knowing that thesupply has these many standard functions. Supply manufacturer need not provide them IF manufacturer specifications do not say so in writing.

Two words that have no business in a PSU selection. Dollars and watts. Neither define a PSU as minimally sufficient - good enough. But can imply a defective supply - insufficient.