Dead Motherboard after storm

[Bishop]

I got a bad motherboard from a HP700 with 67 Caps on board and every one looks perfect, no leaks no swelling and all good name brand.

I can't replace them all but I can replace the most important caps if I can find out which way the power might flow.

Any one out there with knowledge of power flow in motherbaords?

Thaanks

[stj]

Re: Dead Motherboard after storm

thunder-storm followed by a board that wont boot, first suspect is the ethernet controller.
check it for burn marks and see if it's getting hot.

[Bishop]

Re: Dead Motherboard after storm

Board is dead, the only thing I get is the cpu cooling fan kicks, or moves just a little ans stops when the power cord to the power supply is plugged in from the wall. I can't find any cap that appears to have failed.
I have a power supply tester and I know the power supply voltage is correct at all points.
No burn spots anywhere, board looks perfect.
I was thinking about replacing a few key caps if I can identify the most guilty caps that would stall the motherboard.

[stj]

Re: Dead Motherboard after storm

it's not caps.
99% chance the ethernet controller is short-circuit.

the static in the air during a storm goes into the network cable that acts as an antenna.
this is made worse by the transformer on the board or in the ethernet socket - then it hits the controller with several thousand volts!

[goontron]

Re: Dead Motherboard after storm

I have to go with ethernet controller here....

[Bishop]

Re: Dead Motherboard after storm

Has anyone opened a short in the ethernet board wiring?

The board is dead so it would not hurt anything to desolder a point somewhere and use a usb ethernet connection.

Has any tried? I can easily pull a bad cap I should be able to open a link if I can id the junction on the motherboard

[stj]

Re: Dead Motherboard after storm

you generally have to lift the ethernet chip wih hot air and tweezers.

[Bishop]

Re: Dead Motherboard after storm

I had to try.

I removed the metal cover over the ethernet port on the motherboard and I was able to remove the ethernet chip by severing clean the connections of the chip to the motherboard.

I put everything back together and plugged in the power..........nothing,

I believe I did not damage the motherboard or the area around the ethernet plug, it was worth a try. I have a usb network port adapter and was ready to install it, but no change, still dead motherboard.

I'm open to try something else, got any ideas?

[stj]

Re: Dead Motherboard after storm

got a foto? i have never seen a motherboard wih a shielded ethernet PHI chip.

[Bishop]

Re: Dead Motherboard after storm

I took a pic before I put the system back together.

Don't tell me I pull the wrong part.

[goontron]

Re: Dead Motherboard after storm

From what I can see, it's the rtl813* But I can't see much, so I'm probably wrong about something. It looks like the board you pulled was part of the Ethernet, so no loss. A more complete job if anything...

[stj]

Re: Dead Motherboard after storm

RTL8100 network controller

[stj]

Re: Dead Motherboard after storm

what board is it btw.

[Bishop]

Re: Dead Motherboard after storm

It's a D33007 motherboard

It there a simpler way to desolder just a link to the ethernet chip?

Remove a solder joint somewhere with out removing the entire chip?

I'm now on a mission to see how far I can go before placing the motherboard in the can.

Sometimes circuitboard developers leave a place to open a circuit.

[goontron]

Re: Dead Motherboard after storm

It's a D33007 motherboard

It there a simpler way to desolder just a link to the ethernet chip?

Remove a solder joint somewhere without removing the entire chip?

I'm now on a mission to see how far I can go before placing the motherboard in the can.

Sometimes circuitboard developers leave a place to open a circuit.

Opening a jumper won't do. Even if you kill power to the RTL8* chip the southbridge will still "see" it. It will still try and POST it and fail. The chip needs to be completely eliminated. Now, i don't recommend this method, but, you can remove it without a hot air station. Separate the pins from the chip using a pair of needle nose pliers, but don't damage the board in the process. Once you have the pin separated grab the soldering iron and drag solder the pins off the board, then grab the desoldering wick and clean up the mess you made. Again, this is very risky. Don't do this to a customer's gear and don't do this to something you absolutely need to get working, It may screw it worse.

[stj]

Re: Dead Motherboard after storm

if it does not have a pad under it, you could WITH CARE, cut all the pins by pressing a blade down on them where they enter the package.
then lift the chip away leaving the pins.
just make sure none of the pins are touching each other before you test it after.

[lbwlow]

Re: Dead Motherboard after storm

Usually once a LAN chip was shorted it become extremely hot to touch. The proper way to remove it is by desoldering it with hot air station / heatgun. Last time i ghetto remove it by using a lighter, yeap... i know that is a very very bad and wrong way to remove it. But well... i need to get the board working in no time. After i remove it and it still works.

[Bishop]

Re: Dead Motherboard after storm

I was able to get the chip off the motherboard and it looks pretty clean.

I tried to put a microscope at 10 power to the board but I could not get a real good focus because I couldn't get close enough.

Take a look.

[Bishop]

Re: Dead Motherboard after storm

Here's the chip off the board

[Bishop]

Re: Dead Motherboard after storm

Try again