Power supply can zap motherboard?

Hello,

I am curious as to whether a good, working power supply (i.e., one
that has never been zapped by a power surge) can damage a
motherboard. I ask because, recently, the power supply in my computer
went out, so I bought a new Antec 350W power supply and installed
it. My computer worked for two days, then the computer died again - it
would not POST. (Before I bought the new power supply, I checked the
old one with a voltmeter, which gave an inconsistent, low reading on
the gray power good wire.) I checked the new power supply with a
voltmeter and everything reads OK. I tried the power supply in a
friend's computer and it was able to POST. Now, I bought a new
motherboard, but I am afraid to use this power supply in it - is it
possible for it to zap this board too? My friend's computer has worked
since I tried my supply in there; however, he did say the computer
will occasionally reboot out of nowhere since our test. Can a working
power supply really do damage?

Thanks,
Eric Popelka

Eric Popelka wrote:
Hello,

I am curious as to whether a good, working power supply (i.e., one
that has never been zapped by a power surge) can damage a
motherboard.

In the next sentence you say the power supply "went out", so obviously
it was not "good, working"! Yes, PSUs (especially cheaper ones) can take
out a motherboard, add on cards, drives, etc when they go. I've had it
happen to me with a PSU that was starting to go and took everything with it.

I ask because, recently, the power supply in my computer
went out, so I bought a new Antec 350W power supply and installed
it. My computer worked for two days, then the computer died again - it
would not POST. (Before I bought the new power supply, I checked the
old one with a voltmeter, which gave an inconsistent, low reading on
the gray power good wire.) I checked the new power supply with a
voltmeter and everything reads OK. I tried the power supply in a
friend's computer and it was able to POST. Now, I bought a new
motherboard, but I am afraid to use this power supply in it - is it
possible for it to zap this board too?

I think it was your old supply that damaged the board, not the new Antec
one. The board just kept gasping for a few days before finally dying.

My friend's computer has worked
since I tried my supply in there; however, he did say the computer
will occasionally reboot out of nowhere since our test.

There could be a variety of reasons for that after playing around with
the computer's hardware. That said, there's a chance that the Antec
supply is bad, but it seems less likely than other explainations.

Can a working
power supply really do damage?

Thanks,
Eric Popelka



--
spammage trappage: replace fishies_ with yahoo

On Sun, 26 Sep 2004 08:37:33 GMT, Eric Popelka
wrote:

I am curious as to whether a good, working power supply (i.e.,
one that has never been zapped by a power surge) can damage a
motherboard. I ask because, recently, the power supply in my
computer went out, so I bought a new Antec 350W power supply

Why so small PSU? You need margins.

Ken wrote:
On Sun, 26 Sep 2004 08:37:33 GMT, Eric Popelka
wrote:


I am curious as to whether a good, working power supply (i.e.,
one that has never been zapped by a power surge) can damage a
motherboard. I ask because, recently, the power supply in my
computer went out, so I bought a new Antec 350W power supply


Why so small PSU? You need margins.


You didn't ask what components he has. An honest 350W supply is more
than enough for an ordinary setup.

I am confused as to what you really expect of a power
supply. For example, power surges rarely damage properly
designed power supplies. Typically, a power surge bypasses
power supply to enter motherboard directly. Supplies more
often fail due to manufacturing defects and due to humans who
don't first demand written specifications.

Another says a power supply failure damaged his
motherboard. He therefore speculates that all power supplies
can damage motherboards. Reality. If a power supply damaged
a motherboard, then failure was created by the human who did
not first demand written numerical specs. Power supply should
never damage motherboard nor anything else inside a computer
IF power supply contains circuits. Circuits that were even
required and essential 30 years ago.

Cited was a low voltage on Power Good wire. Not sufficient
information. What exactly was the voltage? Always provide
numbers. Any voltage above 2.4 volts is sufficient for Power
Good. Conclusions without numbers are always suspect which
would explain why a power supply was falsely blamed.

Another believes a 350 watt supply is undersized. Again,
more urban myths due to not first learning basic facts. A 250
watt supply is more than sufficient for most every computer.
However this is stated with preconditions. One - is the
manufacturer even honest? Posted in so many newsgroups are,
for example, a power supply that claims 350 watts in big
letters and then says 250 watts in fine print. Two- many
supplies are dumped into N America because so many computer
experts (who are really nothing more than computer assemblers)
don't even know what a power supply does (internally) let
alone understand basic (and internal) supply functions. IOW
computer assemblers only know one spec - price - and foolishly
hope another number - watts - will solve problems if number is
bigger.

A 1000 watt supply need only provide insufficient current to
one voltage Then a computer assembler would insist that we
need 2000 watt supplies. All this when a 250 watt supply
properly designed and selected was sufficient.

Does the 3.5 digit multimeter (analog meter is not accurate
enough) say all voltages meet spec; including the +5VSB
(purple wire)? If all voltages meet spec, then problem is
probably not with power supply. A defective motherboard might
work with one supply but not with another. We live in a
ternary world. For example one supply could have timing
different from another - but both are perfectly good. Master
reset circuit on motherboard was defective. It works with one
supply but not with another - even though both supplies are
perfectly good. Problem is motherboard design. But some
would, instead, speculate a power supply problem. Just
another example of why the computer assembler must first learn
basic operating principles and why we must take numerical
readings with a 3.5 digit multimeter.

If power supply voltages meet specs according to the digital
multimeter (IOW are in upper 3/4 limits of those specs), then
power supply is probably OK. However first and foremost, what
does the manufacture specifically state (in writing) are
functions inside that supply? Does he claim to meet these - a
very abridged list of specs?
Specification compliance: ATX 2.03 & ATX12V v1.1
Short circuit protection on all outputs
Over voltage protection
Over power protection
EMI/RFI compliance: CE, CISPR22 & FCC part 15 class B
Safety compliance: VDE, TUV, D, N, S, Fi, UL, C-UL & CB
Hold up time, full load: 16ms. typical
Dielectric withstand, input to frame/ground: 1800VAC, 1sec.
Dielectric withstand, input to output: 1800VAC, 1sec.
Ripple/noise: 1%

If he does not specifically claim to meet these, then his
product is not sufficient. Again, specs that confuse too many
computer assemblers even though these specs were industry
standard 30 years ago. Too many computer assembler have
experience that is totally useless because it is not tempered
by understanding basic concepts.

A power supply that meets these few specifications should
not be able to damage a motherboard. Too many others say
otherwise only because they bought supplies without first
demanding these specs in writing. They suffered damage
directly traceable to human failure.

Eric Popelka wrote:
I am curious as to whether a good, working power supply (i.e., one
that has never been zapped by a power surge) can damage a
motherboard. I ask because, recently, the power supply in my computer
went out, so I bought a new Antec 350W power supply and installed
it. My computer worked for two days, then the computer died again - it
would not POST. (Before I bought the new power supply, I checked the
old one with a voltmeter, which gave an inconsistent, low reading on
the gray power good wire.) I checked the new power supply with a
voltmeter and everything reads OK. I tried the power supply in a
friend's computer and it was able to POST. Now, I bought a new
motherboard, but I am afraid to use this power supply in it - is it
possible for it to zap this board too? My friend's computer has worked
since I tried my supply in there; however, he did say the computer
will occasionally reboot out of nowhere since our test. Can a working
power supply really do damage?

Thanks,
Eric Popelka

"Eric Popelka" wrote in message
...
Hello,

I am curious as to whether a good, working power supply (i.e., one
that has never been zapped by a power surge) can damage a
motherboard. I ask because, recently, the power supply in my computer
went out, so I bought a new Antec 350W power supply and installed
it. My computer worked for two days, then the computer died again - it
would not POST. (Before I bought the new power supply, I checked the
old one with a voltmeter, which gave an inconsistent, low reading on
the gray power good wire.)


snip

it's possible it was just a surge...
before scrapping the mobo try resetting the bios

there is usually a bios reset jumper near the battery
(consult the mobo manual if you have any questions)

also:
this seems unlikely but i;ve twice seen mobo's not post
simply because the cmos battery was around 1.6 v

it was not high enough to hold the setting...
but not dead enough to cause a reset

"w_tom" wrote in message
...
I am confused as to what you really expect of a power
supply. For example, power surges rarely damage properly
designed power supplies. Typically, a power surge bypasses
power supply to enter motherboard directly.

Total nonsense. Ignore the known wacko.

It sounds like your older defective power supply unit strained your
motherboard with low voltage , and then the motheboard just failed when
rehooked up to a high quality accurate power supply (the Antec). I would
say that hooking your new motherboard up to the Antec should give no
problems.

--
DaveW



"Eric Popelka" wrote in message
...
Hello,

I am curious as to whether a good, working power supply (i.e., one
that has never been zapped by a power surge) can damage a
motherboard. I ask because, recently, the power supply in my computer
went out, so I bought a new Antec 350W power supply and installed
it. My computer worked for two days, then the computer died again - it
would not POST. (Before I bought the new power supply, I checked the
old one with a voltmeter, which gave an inconsistent, low reading on
the gray power good wire.) I checked the new power supply with a
voltmeter and everything reads OK. I tried the power supply in a
friend's computer and it was able to POST. Now, I bought a new
motherboard, but I am afraid to use this power supply in it - is it
possible for it to zap this board too? My friend's computer has worked
since I tried my supply in there; however, he did say the computer
will occasionally reboot out of nowhere since our test. Can a working
power supply really do damage?

Thanks,
Eric Popelka

Eric,

I have experienced something similar and I just built a new machine
using a Antec Phantom 350 PSU - see my thread - P5AD2-E - no power on.

Have you come to a conclusion on this issue?

Regards,

Jaco


--
jacofourie