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Power surge damage

 
 
John
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      05-15-2011, 09:05 PM
My daughter had a power surge bad enough to get through the surge
protector and hit the computer. After the surge, the computer would
boot but had no internet or USB. Thinking that the mobo was fried,
she replaced it and that seemd to cure the problem. But a day later,
ir came back -- no internet, no USB. If she turns it off for a while
and back on, it's okay, at least for a while.

She's asking my opinion of what else could be wrong and I'm thinking
it sounds like PSU. Do others agree? If not, then what else might it
be?


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-- John
 
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Paul
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      05-15-2011, 11:43 PM
John wrote:
> My daughter had a power surge bad enough to get through the surge
> protector and hit the computer. After the surge, the computer would
> boot but had no internet or USB. Thinking that the mobo was fried,
> she replaced it and that seemd to cure the problem. But a day later,
> ir came back -- no internet, no USB. If she turns it off for a while
> and back on, it's okay, at least for a while.
>
> She's asking my opinion of what else could be wrong and I'm thinking
> it sounds like PSU. Do others agree? If not, then what else might it
> be?
>
>
> Reply-to address is real
> -- John


One question would be about the surge itself. Were other devices in the
house affected ? Was the surge protector damaged ? Some surge protectors
have a status LED that lights up when the surge protector itself is fried.
(Of several I own, one has the LED.)

Naturally, the power supply is the first thing to feel the effects of the
surge. And with the limited feedback range on the control loop, it's also
possible the overvoltage could be transferred through to the outputs.
(The transformer within the power supply likely has a breakdown rating
of more than 1100 volts, and lightning could easily jump across there
and go right into the DC outputs. The sticker on the ATX supply that
says "hi pot tested", verifies that the transformer can take at
least 1100 volts across the insulation inside it. That is intended to
stop certain kinds of power company issues going straight into the PC,
but can't stop lighting, because nothing stops a direct lightning
hit.)

Now, say the primary rails 3.3V, 5V, 12V are out of spec. The power supply
itself has a signal Power_Good on the main cable, which is supposed to
detect when the voltages are close to the final values, at start up. The
motherboard won't start running unless there is Power_Good asserted by
the power supply. The motherboard stays in reset, until Power_Good is
asserted. If the rails were substantially low, then the computer would
sit there with a black screen, fans running.

To have your current symptoms then, you'd need a rail to drop to a low
voltage, Power_Good to remain asserted, and other circuits on the motherboard
to still "feed good enough" for the computer itself not to crash. Which
seems a bit strange.

I think there is more to it than power supply, but swapping in another
supply for a test would be a good thing to try. If someone has a
multimeter handy, they can take the side off the PC, clip the black
ground lead to a screw on the I/O plate on the back of the computer,
then take the red lead, and probe the exposed metal within each hole
of the nylon shell of the main connector. In rough round numbers, the
primary rails should be within 5% tolerance. So if you probed where the
yellow wire went into the nylon shell of the PSU connector, the meter
would read 12.00 on the 20V range when you touched the metal inside where
the yellow wire meets the motherboard. A 5% tolerance, means any value
between 11.4V and 12.6V is acceptable.

Power supply specs, oldest to newest... Pinout tables...

http://web.archive.org/web/200304240...12V_PS_1_1.pdf (page 27)

http://www.formfactors.org/developer...X12V_1_3dg.pdf (page 30)

http://www.formfactors.org/developer...public_br2.pdf (page 37)

The rails used for Internet and USB, could be different as well. USB
at the interface pads, may be using the +5VSB rail. And if that was
out of spec enough, the PC would shut off because there isn't enough
voltage to run supervision logic. The Internet would rely on several voltages,
such as 3.3V or an onboard regulator that converts 3.3V into an even
lower voltage for the core logic of the LAN chip. (Many LAN chips use
two rails, one rail being internal on the motherboard.) And I really have
to wonder why the PC is still running, if multiple rails are out of
whack. You'd think something would crash or shut down.

Another question you'd have to ask, is whether the hard drive(s) were
damaged. The hard drive has surge protection devices on +5V and +12V.
A sustained overvoltage on either rail, causes the surge protector
device on the drive to get burned. Such a situation may arise on a
computer with a 250W Bestec brand supply, and a failure there
comes from the supply output rising on its own, to a higher than
normal value.

I'm not liking the symptoms here, because I don't have a good explanation
for them. You can try another supply, especially if you don't have
a multimeter. Swapping is easy to do, even for a novice, as long as
they take pictures with a digital camera and put everything back the
way they found it. If you aren't there personally to help, you can
use pictures from this web page, to aid in discussions about
connectors (such as "why are these Molex 1x4 connectors on the
hard drives, so hard to remove" :-) ). When removing the Molex 1x4
from a drive, you should use your fingers, as attempting to apply
tools to it, the tools slip off. Wiggling it is what I attempt
to do. Modern supplies have a compression section on either
side of the Molex, which when compressed, pushes against the
drive and eases the connector out. But the older connectors
don't have that feature, and it takes a fair bit of finger
strength to get them to budge.

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

(Hard on the fingers...)
http://www.playtool.com/pages/psucon...ipheralpic.jpg

Good luck, and post back if the symptoms aren't resolved. I
feed there is more at work here than just supply. Maybe a
USB device is damaged and overloading something ? With all
excess USB devices disconnected, does the LAN still run ?

Paul
 
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john
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      05-16-2011, 01:09 AM
On Sun, 15 May 2011 19:43:00 -0400, Paul <(E-Mail Removed)> wrote:

>John wrote:
>> My daughter had a power surge bad enough to get through the surge
>> protector and hit the computer. After the surge, the computer would
>> boot but had no internet or USB. Thinking that the mobo was fried,
>> she replaced it and that seemd to cure the problem. But a day later,
>> ir came back -- no internet, no USB. If she turns it off for a while
>> and back on, it's okay, at least for a while.
>>
>> She's asking my opinion of what else could be wrong and I'm thinking
>> it sounds like PSU. Do others agree? If not, then what else might it
>> be?
>>
>>
>> Reply-to address is real
>> -- John

>
>One question would be about the surge itself. Were other devices in the
>house affected ? Was the surge protector damaged ? Some surge protectors
>have a status LED that lights up when the surge protector itself is fried.
>(Of several I own, one has the LED.)
>
>Naturally, the power supply is the first thing to feel the effects of the
>surge. And with the limited feedback range on the control loop, it's also
>possible the overvoltage could be transferred through to the outputs.
>(The transformer within the power supply likely has a breakdown rating
>of more than 1100 volts, and lightning could easily jump across there
>and go right into the DC outputs. The sticker on the ATX supply that
>says "hi pot tested", verifies that the transformer can take at
>least 1100 volts across the insulation inside it. That is intended to
>stop certain kinds of power company issues going straight into the PC,
>but can't stop lighting, because nothing stops a direct lightning
>hit.)
>
>Now, say the primary rails 3.3V, 5V, 12V are out of spec. The power supply
>itself has a signal Power_Good on the main cable, which is supposed to
>detect when the voltages are close to the final values, at start up. The
>motherboard won't start running unless there is Power_Good asserted by
>the power supply. The motherboard stays in reset, until Power_Good is
>asserted. If the rails were substantially low, then the computer would
>sit there with a black screen, fans running.
>
>To have your current symptoms then, you'd need a rail to drop to a low
>voltage, Power_Good to remain asserted, and other circuits on the motherboard
>to still "feed good enough" for the computer itself not to crash. Which
>seems a bit strange.
>
>I think there is more to it than power supply, but swapping in another
>supply for a test would be a good thing to try. If someone has a
>multimeter handy, they can take the side off the PC, clip the black
>ground lead to a screw on the I/O plate on the back of the computer,
>then take the red lead, and probe the exposed metal within each hole
>of the nylon shell of the main connector. In rough round numbers, the
>primary rails should be within 5% tolerance. So if you probed where the
>yellow wire went into the nylon shell of the PSU connector, the meter
>would read 12.00 on the 20V range when you touched the metal inside where
>the yellow wire meets the motherboard. A 5% tolerance, means any value
>between 11.4V and 12.6V is acceptable.
>
>Power supply specs, oldest to newest... Pinout tables...
>
>http://web.archive.org/web/200304240...12V_PS_1_1.pdf (page 27)
>
>http://www.formfactors.org/developer...X12V_1_3dg.pdf (page 30)
>
>http://www.formfactors.org/developer...public_br2.pdf (page 37)
>
>The rails used for Internet and USB, could be different as well. USB
>at the interface pads, may be using the +5VSB rail. And if that was
>out of spec enough, the PC would shut off because there isn't enough
>voltage to run supervision logic. The Internet would rely on several voltages,
>such as 3.3V or an onboard regulator that converts 3.3V into an even
>lower voltage for the core logic of the LAN chip. (Many LAN chips use
>two rails, one rail being internal on the motherboard.) And I really have
>to wonder why the PC is still running, if multiple rails are out of
>whack. You'd think something would crash or shut down.
>
>Another question you'd have to ask, is whether the hard drive(s) were
>damaged. The hard drive has surge protection devices on +5V and +12V.
>A sustained overvoltage on either rail, causes the surge protector
>device on the drive to get burned. Such a situation may arise on a
>computer with a 250W Bestec brand supply, and a failure there
>comes from the supply output rising on its own, to a higher than
>normal value.
>
>I'm not liking the symptoms here, because I don't have a good explanation
>for them. You can try another supply, especially if you don't have
>a multimeter. Swapping is easy to do, even for a novice, as long as
>they take pictures with a digital camera and put everything back the
>way they found it. If you aren't there personally to help, you can
>use pictures from this web page, to aid in discussions about
>connectors (such as "why are these Molex 1x4 connectors on the
>hard drives, so hard to remove" :-) ). When removing the Molex 1x4
>from a drive, you should use your fingers, as attempting to apply
>tools to it, the tools slip off. Wiggling it is what I attempt
>to do. Modern supplies have a compression section on either
>side of the Molex, which when compressed, pushes against the
>drive and eases the connector out. But the older connectors
>don't have that feature, and it takes a fair bit of finger
>strength to get them to budge.
>
>http://www.playtool.com/pages/psucon...onnectors.html
>
>(Hard on the fingers...)
>http://www.playtool.com/pages/psucon...ipheralpic.jpg
>
>Good luck, and post back if the symptoms aren't resolved. I
>feed there is more at work here than just supply. Maybe a
>USB device is damaged and overloading something ? With all
>excess USB devices disconnected, does the LAN still run ?
>
> Paul



Thanks, Paul, for the extensive and detailed reply. I've passed it
along to my daughter (a techie who's as capable of understanding it as
I am).

Yes, there were other devices in the house that were damaged -- a
wired smoke alarm and the controller board for the furnace and (she
thinks) the router. Another computer in the house is also misbehaving
but they haven't gotten into that one yet.

The latest word is that she got the usb working by deleting the ports
and letting them be re-discovered and reinstalled. The network is
flakey -- works most of the time but not always. She's wondering if
the router was damaged; she's on a wired port and sees the flakiness,
but a laptop using a wireless connection seems to work fine. (I don't
know whether the laptop was plugged in when the surge hit.)

From the sound of it, the drives are okay and the computer never
showed any damage except forthe usb and enet misbehavior. So it's
starting to look like the computer -- with its mobo replaced -- may be
okay after all. (Her big fear was that the real problem was somewhere
besides the board -- e.g., the psu -- and that she had fried the
second board by connecting it. That appears not to be the case.)



-- john
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geoff
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      05-17-2011, 02:34 PM
Is the internet cable?

--g


 
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john
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      05-17-2011, 11:15 PM
On Tue, 17 May 2011 10:34:34 -0400, "geoff" <(E-Mail Removed)> wrote:

>Is the internet cable?
>
>--g
>

Yes, cable internet.

-- john
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geoff
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      05-18-2011, 01:56 AM
I also had a lightning strike near the house. It took out the garage door
opener, garbage disposal, and the dryer. The flexible tubing that fed gas
to the hot water heater broke open with flames shooting out.

Everything was fixed but about every two or three weeks I had to reboot the
router (new) because the connection was lost. When I switched to digital
phone, the cable guy said the connectors were black as pitch. He changed
the cable going from the house to the road and that seem to fix the
connection issue.

--g


 
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westom
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      05-18-2011, 03:18 AM
On May 15, 9:09 pm, john <(E-Mail Removed)> wrote:
> (Her big fear was that the real problem was somewhere
> besides the board -- e.g., the psu -- and that she had fried the
> second board by connecting it. That appears not to be the case.)


Paul's suggestion of using the multimeter would accuse or exonerate
the power supply in but a minute - no more doubts. IOW take
measurements of key voltages. If the three digit numbers are good,
then move on to other suspects.

Appears she had a surge on AC mains. This due to no properly earthed
'whole house' protector. So the surge was inside hunting
destructively for earth ground. Normally protection inside he PSU
makes these surges irrelevant. But an adjacent protector can connect
that surge directly to the motherboard. Bypass protection inside the
supply.

Well, surge incoming to the motherboard. Apparently outgoing via
the USB port and router. To have damage, everything must have both an
incoming and outgoing path. The surge can pass through everything
from cloud to earth. But only some items in that path to earth get
damaged.

She needs some means of testing the interconnection between USB and
router. The router has an address typically of 192.168.0.1 or
192.168.1.1. So using Command Prompt window, enter the command
"PING -t 192.168.x.1" without quotes and with x replaced by 0 or 1.
(To better learn that IP address, enter "IPCONFIG /ALL" in the Command
Prompt window.)

That ping should occur constantly and with response times of less
than 20 milliseconds. If yes, then the interconnection is good. Move
on to other suspects.

Well, the surge then may have gone from router to earth via the phone
or cable line. So "PING -t xxxx" where xxxx is some internet
site. Again, that Ping must be constant without interruptions (but
will be a longer response time). If good, then move on to other
suspects.

These tests (even from the power supply) provide numbers. Post
those numbers here to learn of more information embedded in those
numbers.
 
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