hp pav 7970 motherboard replacement

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DK1000

Hi, I have an HP pavilion 7970 P4 PC about 7 years old. I went to turn
it on this morning, and the power wouldn't go on. I did notice that
when I pull/put the AC power cord in the PC, a little green LED on the
back of the PC to the right of the AC plug-in flashes once very
quickly.

I took the PC to a local repair shop, them suspecting a fried power
supply as I did. They replaced the power supply, the machine turned on
and the green LED under the front power switch lit up, and I could
hear the fan, but the fan didn't sound right to me.

When nothing came up on the monitor (the monitor was completely blank,
no start-up type screens at all), they told me the motherboard was
also fried. The repair guy said you can no longer get the motherboard
for the 7970 nor the memory, and I was better off just getting another
PC, of which they had some there that looks like they were used.

I didn't buy another PC (yet), as I have another desktop and a laptop
that are hooked into my router. I asked the guy to package the hard
drive into a USB case so I can get my stuff off there (hopefully the
HD didn't fry). So that's $65 and I can pick that up tomorrow, as he
didn't have any of the right enclosures on hand to make it an
external. I brought the rest of the 7970 back home with me.

I just did a search online, and one site did say a fried motherboard
can fry the power supply to protect other components. Does all this
sound plausible? If so, what can I look for on eBay or elsewhere as
far as a motherboard that will fit the 7970? Brand name and model
number, as a search for a 7970 board goes to HP and they want almost
$300 it seems. My eBay search for 7970 motherboard produced nothing,
but it gave me a lot of hits for HP motherboard, but all the names are
"Greek" to me.

One other note, is that I had an APC SmartUPS 700 supposedly
protecting that equipment, but that has been shutting down on it's own
randomly the last few days, and then I noticed a LED that says "low
voltage". I didn't want to take any chances, so I powered down the
7970 last night, and it powered down and shut off without a hitch. I
plugged it into a different surge protector before I went to power it
on today, and it wouldn't power on. Strange that something would
seemingly go bad when it was off. We did have a good lightning storm
the day before, but that didn't seem to affect the PC at the time, and
I in fact rebooted it a couple times since the storm with no
problems.

Thanks,

Dan
 
DK1000 said:
Hi, I have an HP pavilion 7970 P4 PC about 7 years old. I went to turn
it on this morning, and the power wouldn't go on. I did notice that
when I pull/put the AC power cord in the PC, a little green LED on the
back of the PC to the right of the AC plug-in flashes once very
quickly.

I took the PC to a local repair shop, them suspecting a fried power
supply as I did. They replaced the power supply, the machine turned on
and the green LED under the front power switch lit up, and I could
hear the fan, but the fan didn't sound right to me.

When nothing came up on the monitor (the monitor was completely blank,
no start-up type screens at all), they told me the motherboard was
also fried. The repair guy said you can no longer get the motherboard
for the 7970 nor the memory, and I was better off just getting another
PC, of which they had some there that looks like they were used.

I didn't buy another PC (yet), as I have another desktop and a laptop
that are hooked into my router. I asked the guy to package the hard
drive into a USB case so I can get my stuff off there (hopefully the
HD didn't fry). So that's $65 and I can pick that up tomorrow, as he
didn't have any of the right enclosures on hand to make it an
external. I brought the rest of the 7970 back home with me.

I just did a search online, and one site did say a fried motherboard
can fry the power supply to protect other components. Does all this
sound plausible? If so, what can I look for on eBay or elsewhere as
far as a motherboard that will fit the 7970? Brand name and model
number, as a search for a 7970 board goes to HP and they want almost
$300 it seems. My eBay search for 7970 motherboard produced nothing,
but it gave me a lot of hits for HP motherboard, but all the names are
"Greek" to me.

One other note, is that I had an APC SmartUPS 700 supposedly
protecting that equipment, but that has been shutting down on it's own
randomly the last few days, and then I noticed a LED that says "low
voltage". I didn't want to take any chances, so I powered down the
7970 last night, and it powered down and shut off without a hitch. I
plugged it into a different surge protector before I went to power it
on today, and it wouldn't power on. Strange that something would
seemingly go bad when it was off. We did have a good lightning storm
the day before, but that didn't seem to affect the PC at the time, and
I in fact rebooted it a couple times since the storm with no
problems.

Thanks,

Dan
Click to expand...

It's seven years old. It wasn't worth installing a power supply, much less a
main board. For the same money they want for the board, you can buy a new
box
 
I just did a search online, and one site did say a fried motherboard
can fry the power supply to protect other components. Does all this
sound plausible? ...
One other note, is that I had an APC SmartUPS 700 supposedly
protecting that equipment, but that has been shutting down on it's own
randomly the last few days, and then I noticed a LED that says "low
voltage".
Click to expand...

Helpful would be a PC tech that first identified a failure rather
than shotgun. The actual failure (failed part or subsystem identified
inside a failed component) would have gone a long way to explaining
why your failure happened.

A motherboard cannot fry any minimally acceptable power supply - a
standard that even existed 35 years ago. A minimally acceptable power
supply must never cause motherboard or other electronics damage.
However, those who never learned how electricity works also tend to
buy power supplies only on price and watts. Therefore functions that
were standard even 35 years ago can be missing to sell that power
supply for less than $60 full retail.

Normal is for a surge protector located too far from earth ground
and too close to appliances to make electronics damage easier. For
example, in one location, a surge was traced by literally replacing
every damaged integrated circuit; all machines restored. Only then
did we fully understand how that surge created damage.

All networked computers were powered off. Two were on plug-in
protectors. An incoming hot (black) wire surge was shunted by
protectors onto green (safety ground) wire and into adjacent computer
motherboards. Surge exited via the network and into a third networked
computer. Then outgoing on that computer's modem to earth ground via
the telco 'supplied for free' surge protector. Established was a
complete electrical circuit from cloud to earth.

Those plug-in protectors provided a surge more paths to find earth
ground destructively through powered off computers. No difference
whether electronics are on or off. If a surge is not earthed before
entering a building, then a surge may find numerous destructive paths
to earth via appliances.

So what was damaged in your computer? Motherboard AND power
supply? Hardly. More likely a tech kept replacing things until
something worked; did not first identify the failed part. Therefore we
don't know what path a surge took destructively through your computer
- or even if a surge causes failure.

LED now says low voltage. Which voltage is reported? If power
supply voltage, well, the tech could have measured that with a meter
in less than 30 seconds to know with certainty. Normal is for a power
supply to be defective (one voltage too low) and yet a computer boots
just fine for months. Most techs will replace a power supply, see
computer boot, then assume power supply is OK. Wrong. A defective
power supply can still boot a computer. That new power supply is not
OK until numbers from a 3.5 digit multimeter confirm voltages when
computer max loads that power supply.

One possible scenario. Power supply failed either due to a
manufacturing (component) defect or due to overstress when internal
protection circuits were confronted by a lightning surge (APC
protector did exactly what it specs said it would do for that kind of
surge - nothing). Tech replaced the power supply with a defective
one. Sufficient to boot a computer but the tech never bothered to
confirm supply voltages with a meter. A marginal supply now created
intermittent failures and the low voltage indicator. So tech does
what he understands. Blame something else. He selects a motherboard
for blame.

Notice the pattern. At no time does he first use standard
diagnostic methods to determine what is wrong. Instead he jumps to
conclusions and replaces parts until something works. He shotguns.
As a result he ends up with a computer being booted by a completely
defective (or undersized) power supply.

The meter is so complex as to be sold only to Kmart shoppers. You
can buy one for less than $20 in Lowes or Wal-Mart. Then you can see
the numbers that your tech did not. Simply get computer multitasking
to as many peripherals as possible. Then touch meter probes to any
one of orange, red, purple, and yellows wires. Record and report
those numbers. Connector chart to locate each color:
http://www.hardwarebook.net/connector/power/atxpower.html

You need only perform that limited measurements from this larger
procedure:
http://tinyurl.com/yvf9vh
Those numbers must exceed 3.23, 4.87, or 11.7 volts.

Based only upon what was posted, I doubt motherboard is defective.
Get the meter. Make those measurements. Learn what is defective
before replacing anything.
 
DK1000 said:
Hi, I have an HP pavilion 7970 P4 PC about 7 years old. I went to turn
it on this morning, and the power wouldn't go on. I did notice that
when I pull/put the AC power cord in the PC, a little green LED on the
back of the PC to the right of the AC plug-in flashes once very
quickly.

I took the PC to a local repair shop, them suspecting a fried power
supply as I did. They replaced the power supply, the machine turned on
and the green LED under the front power switch lit up, and I could
hear the fan, but the fan didn't sound right to me.

When nothing came up on the monitor (the monitor was completely blank,
no start-up type screens at all), they told me the motherboard was
also fried. The repair guy said you can no longer get the motherboard
for the 7970 nor the memory, and I was better off just getting another
PC, of which they had some there that looks like they were used.

I didn't buy another PC (yet), as I have another desktop and a laptop
that are hooked into my router. I asked the guy to package the hard
drive into a USB case so I can get my stuff off there (hopefully the
HD didn't fry). So that's $65 and I can pick that up tomorrow, as he
didn't have any of the right enclosures on hand to make it an
external. I brought the rest of the 7970 back home with me.

I just did a search online, and one site did say a fried motherboard
can fry the power supply to protect other components. Does all this
sound plausible? If so, what can I look for on eBay or elsewhere as
far as a motherboard that will fit the 7970? Brand name and model
number, as a search for a 7970 board goes to HP and they want almost
$300 it seems. My eBay search for 7970 motherboard produced nothing,
but it gave me a lot of hits for HP motherboard, but all the names are
"Greek" to me.

One other note, is that I had an APC SmartUPS 700 supposedly
protecting that equipment, but that has been shutting down on it's own
randomly the last few days, and then I noticed a LED that says "low
voltage". I didn't want to take any chances, so I powered down the
7970 last night, and it powered down and shut off without a hitch. I
plugged it into a different surge protector before I went to power it
on today, and it wouldn't power on. Strange that something would
seemingly go bad when it was off. We did have a good lightning storm
the day before, but that didn't seem to affect the PC at the time, and
I in fact rebooted it a couple times since the storm with no
problems.

Thanks,

Dan
Click to expand...

HP Pavilion 7970 overview
http://h10025.www1.hp.com/ewfrf/wc/...e=bph06669&dlc=en&lc=en&jumpid=reg_R1002_USEN

The motherboard is socket 423, with a P4 1.5GHz, and the memory type is
RDRAM. Chipset is Intel 850. Graphics are via GeForce2 MX 200 32 MB,
and since the board has an AGP slot, that is probably where the
graphics card is located.

Finding a replacement, to reuse the components, wouldn't be that easy.
It is possible you could find some S423 board to reuse the processor,
but a different kind of RAM might be used by the replacement board.

The HP parts store, shows a red "X" through all the components listed
as being part of the 7970, meaning they don't stock them. The motherboard
isn't even listed so I couldn't get more information about it. If the
part number was there, that makes it easier to shop for a replacement
board on the Internet.

Since you mention lightning, anything is now possible. If you were present
at the time, then you might recollect how close the lightning came, whether
the lights blinked, whether the UPS beeped or flipped to battery for a
short instant. A UPS is not guaranteed to protect equipment (nothing can
really handle a direct lightning strike), and there are different internal
architectures for UPSes (some better than others).

For example, my APC 650 is an SPS, meaning it is a "straight piece of wire"
until the instant that the power fails, and it flips to battery. So other
than the surge protection components in mine, it really isn't offering
any other protection mechanisms. The next level of UPS offers "line conditioning",
where the UPS tries to do a little more to regulate the output voltage.
A true double conversion type (AC-DC-AC), where all power is filtered by
the battery, is another way to do it, and wouldn't pass upsets quite as
easily, from input to output. A few years ago, one of those might cost $1000.
(They tend to buzz, run hot, have a fan, so you know you're in the room with
one.) And you have to be very careful when shopping, that the architecture of the
UPS you're buying, is what you think it is. The specs won't say in clear
English, how it is implemented (double conversion versus delta conversion).

http://www.apcmedia.com/salestools/SADE-5TNM3Y_R5_EN.pdf

Lightning can follow ground conductors, follow phone lines, be induced
into Ethernet cables, so there are in fact many potential paths for
lightning to blow stuff up. The A.C. isn't the only path to consider.

Paul
 
Thanks much everyone for the prompt and thorough replies. There is a
lot to digest here and some of it may be over my head, so I'm going to
re-read a couple of times. I just found a friend of a neighbor who has
a smaii home based PC repair business, I'll take it there tomorrow,
and if we can't get the original components, I'll have him rebuild
what's needed, even if we need a different MB and memory, etc. I'll
print this info out if needed. Again, thanks much,

Dan
 
kony said:
Seven years old is at least new enough to reasonably run
Win2k or XP, handle internet, office, email, etc - the most
common tasks. It would easily be worth the $25 or so a PSU
should cost for a system old enough that it isn't likely to
use a lot of power, to get it working again if it was known
that all it needed was a power supply. A replacement
motherboard, so long as it need not be identical HP board,
might be had for about the same $25, it would just take a
lot of hunting to find one at a surplus 'site or ebay for
example.

Granted, the more parts there are that need replaced the
less worthwhile it becomes to do so, but for many people it
would be madness to spend a few hundred instead of under
$100 when they don't really need a newer system from a
performance standpoint, though at 7 years it is also a good
idea to replace the hard drive to decrease the chances of
data loss from eventual failure of the original drive.
Click to expand...

Except that he's not doing this himself. It gets a little more expensive
when you pay a shop to do the troubleshooting and repair. Unless it was a
high end machine to begin with, it's probably not worth the expense, not to
mention, a new machine will come with a new hard drive
 
kony said:
Perhaps, but if one is willing to try doing the work
themselves, several parts might be replaced at no greater
cost than the shop's bench fees alone. The shop might even
be a source of cheap used parts to DIY, it can vary a lot
what one shop charges vs another for used stuff. A shop
certainly likes to sell the full package of diagnosis and
repair plus new parts, but if all they can get is to sell
off some of the used parts, it's money for parts they'd
often be throwing away in the dumpster otherwise.
Click to expand...

I don't know how many shops give stuff away. That's not the business they're
in, but you're correct, if they could steer him in the right direction and
sell him the parts, they'd both make out
 
kony said:
Did I write "give stuff away" or did I write cheap? Suppose
for a second that a shop has a leftover old motherboard,
this actually happens quite often when people abandon an old
system they don't want to pay the fees on, or when there is
a failure to the point where a shop gives a small discount
off the new system to take the old one from them.

It is the business they're in to sell whatever they can.
Including used parts. Like I wrote before, some shops
charge a lot more than others for the used parts. Some will
sell old used stuff for $5 to $10 a part. Some can't even
sell what they take in for $5 and end up throwing excess
away, though it'd be worth the money just to get a board off
their shelf instead of rooting through a dumpster with the
hope you grab good boards instead of bad ones.
Click to expand...

I wrote "give stuff away" meaning "cheap". It seems all to often when
someone has an obscure or obsolete part that a customer can't find anywhere
else, the price goes up
 
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