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Laptop NIC's frying:  3rd one at this desk!

Posted on 2005-05-04
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This is by far the most bizarre situation I've encountered in my 10+ years working in IT Support.

We recently moved a group of users to a new space in our office.  We had to have new CAT5e cable run to this area, as well as new power lines and cubicles.  Most of the guys in this area are using the R40 IBM Thinkpad.  

Well, about 1 month into this move, 1 of the users comes to us and says his on-board NIC no longer worked.  Puzzled, we took a look at it and confirmed it wasn't working.  I noticed one of the Ethernet pins was just a little bent (not much though), so I assumed that must be the problem.  We pulled his hard drive and place it into an identical R40 Thinkpad.  I tested the NIC on this new laptop and everything looked good.  Problem solved right?  Wrong.

About 2 weeks later, the same guy came back and said his NIC stopped working on this new laptop.  So now we're thinking "OK what's this guy doing over there.."  We took this 2nd laptop and examined the NIC carefully.  No bent pins or anything.  He's pretty responsible and would have told us if he had done anything careless such as pick up the laptop while it's plugged in.  Seeing that this was laptop #2, we went ahead and swapped out the patch cable at his desk as well as the patch cable on the switch to his port.  Our network admin took a look at the switch port and didn't see any errors.  So, we concluded this was just a weird coincidence.  We swapped out laptop #2 with laptop #3.

Today (about 1 week later), the NIC on this 3rd laptop has now stopped working.  It was working fine, now it's not.  None of us have heard about voltage traveling over CAT5e cable then frying a laptop.  I've heard of a bad nic causing a port on a Cisco switch to disable itself, but not the other way around.  This 3rd laptop is doing the same exact thing as the other 2.  The NIC shows up in Device Manager, so the drivers are loaded.  When you plug a cable into it you get no Link light.  Windows thinks the network cable is unplugged.  It's basically just fried and dead.  All 3 of them.

We decided to hook up a Fluke Microscan tester to his jack at this desk to test the run between his desk and the patch panel.  No errors...all pairs are clean.

So...we swapped out laptop #3 with laptop #4 today (identical R40 IBM ThinkPad).  We also connected a hub to his jack and have the laptop connected to the Hub.  This way, if something is causing a network device to fry, we are willing to sacrifice this hub to protect this 4th laptop.

So, anyone here ever heard of something causing an on-board NIC to fry over and over?  There's hardly any voltage at all going through a CAT5e run, so it can't be that.  I noticed that his surge protector is sitting on his desk and it wasn't before he moved.  It's about 12 inches away from the back of his laptop...but c'mon that couldn't be it, could it?  

As an FYI, when we attempt to boot to the network from a DOS Boot Disk, the NIC still wont work..so that pretty much eliminates any software-related issues so re-imaging, re-installing the drivers, etc. wont help at all.   The CAT5 that was run to this new space is about 150 feet and is all in 1 bundle in the ceiling.  I’m wondering if this bundle is near a power source or motor somewhere in the ceiling, and a few cables are picking up a load, and then transferring this voltage to the laptop NIC.  At this point, it could be anything.

Any suggestions as the possible cause of this are welcome.  Thanks!
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Question by:PlaceIT
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by:davidis99
ID: 13929020
What other devices are plugged into the surge protector aside from the laptop?   Does the user have a persona lair cleaner or ionizer?  those can be lethal to electronics if the power cable for the device gets wrapped up with data cables - wall jacks may not be damaged, but I've seen NICs, motherboards, and switch/hub ports get toasted this way.  
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by:rid
ID: 13929639
I think I'd investigate the run of his "personal" cable (from the switching rack to his outlet). TP cable is designed not to pick up interference (shielding and twisted pairs), but heavier surges may be transferred to the cable as an entity, with a voltage respecitve to ground, and such a spike may just cencievably hit and damage the NIC input circuitry. The switch in the other end may be more resilient.

This is very hypothetic, of course, and assumes a source of interference somewhere along the cable bundle that affects "his" cable more than others. It could be anything that has to do with mains power; a reactor or HF unit for flourescent tube lighting, a contactor or relay, a motor/compressor unit for AC equipment, or a cable to some such unit running parallel to his networking cable for some length.
/RID
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by:gecko_au2003
ID: 13930491
You said :

"I noticed that his surge protector is sitting on his desk and it wasn't before he moved.  It's about 12 inches away from the back of his laptop...but c'mon that couldn't be it, could it? "

Well one way to find out is if you move it as far away as possible from the laptop :) Just a thought.
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by:nobus
ID: 13933796
i support rid's idea of checkin his personal cable; a short to an ac line  can cause weird things, and will burn out the nic's coupling device easily. I say this, because you mentioned that it is all new cabling, and pulling the cables can just make those things happen.
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by:Watzman
ID: 13935649

It's a wierd problem and there isn't an obvious answer, but it's possible for Cat 5 cable to pickup inductive spikes from nearby electricla wiring.  The rule is that cat 5 cable should ideally cross AC power lines at right angles.  The worst case is running "parallel" and close to a power run, or even through the same conduit or holes in joists.  They don't have to actually touch each other, this can occur via "inductive" pickup.  But normally all of the cat 5 lines (to the other cubicles) would be run together, and you would see problems with other users also.  Installing the hub was a good idea, but I'd go one step further:  Many of the higher end surge supressors and even many low-end UPS' have surge supressors for telephone and LAN lines.  I'd install one of those (and I prefer a UPS to a surge supressor, 350 VA UPS' are only about $30, and I'm talking APC brand).
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by:PlaceIT
ID: 13935935
The only thing plugged into the surge protector is an AC adapter for his cell phone and the AC adapter for the laptop.  This surge protector also has a "grounded" light which is illuminated, so I think we're safe there.  Just because this is a mystery, I'm wanting to change 1 thing at a time here so we can pinpoint the source of the problem.  These Thinkpads are under warranty, so it's not a huge deal we've lost a few NIC's.  

It looks like we're going to have to examine the bundle of cables and see where it goes.  There are AC units and plenty of flourescent lights up there, and it seems the concensus from these posts is that the CAT5 is picking up something nearby.  I will pop come ceiling tiles and post my findings later today.
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by:ddrdan
ID: 13950395
Does he take the laptop home?
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by:gecko_au2003
ID: 13950411
The only thing im wondering is in this office enviroment or whatever you want to call it, are there desktop pc's that are hooked up to this network, if so then how come it only affects the laptops NIC's ??
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by:ddrdan
ID: 13950419
Sorry, hit the "submit" before I was done.

Is he using a cell phone connection to his laptop?
What other peripherals is he connecting to the unit?
You did not say if you gave him a new AC adapter with the new units?
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by:bobo_tech
ID: 13956096
This is really weird.  My buddy has the same exact laptop.  A ibm thinkpad R40.  The lan port on that one quit working as well.  It was barely working when he gave it to me (it would work once in a while (showed link) but then it would quit working and windows would report no connection).  It then just quit working all together.  Windows showed noactivity (no link lights) and it wasn't a software problem.

I went and tried updated drivers, no fixy.  I then formatted the hard drive and tried again, still no link light.

Finally I went and stripped the laptop to its motherboard and reflowed the solder pads on the network port.  My logic was that a cold/broken solder joint might be causing this issue.  Put the whole thing back together and tried it once again, still nothing.  No signal.  Windows thinks the port is completely dead.

My guess is that the port is very sensitive to the littlest deviation from the norm and it has a tendency to blow the ports.
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by:PlaceIT
ID: 13962383
To answer the questions above:

1. Yes he does take this laptop home.  Good question.  Maybe something at home is the culprit here.  It seems to "break" when it's here at the office though.
2. Only peripheral is an external USB Optical mouse.  Only 2 things plugged into his Surge Protector:  Laptop and Cell Phone charger.  Surge Protector is a Belkin and has a "Grounded" light which is lit green, indicating good clean power.
3. We did not swap out his AC Adapter.  Good suggestion.

I pulled ceiling tiles and followed the run of cables and they don't cross anything high voltage.  They did a good job making sure the CAT5 was clear from anything.  I don't think it's the CAT5, but appears to be something more localized.  Based on the suggestions above it could be one of the following:

1. The power at his desk.  We can draw power from an adjacent cubicle and see if that helps.
2. His AC Adapter.  (ddrdan's comment) Swap it out, see what happens.
3. Something at home is stressing the laptop, causing the Ethernet port to fail.

Bobo_Tech's comment in interesting.  The laptops behaved just as he described.  If this is the case, then we should see this next R40 die very soon.

It looks like it may take a while for me to find the solution.  I may never know.  I will try these various suggestions and post anything new that develops.  Thanks for all the comments.
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bobo_tech earned 750 total points
ID: 13965233
Honestly, the best and cheapest way to fix the issue woudl be to use wireless (you can get internal minipci cards for cheap on ebay that fit perfectly into the minipci slot underneath the laptop covers on the bottom of it) and/or get a cardbus network card if you have to have wired.  You also could probably get a usb dongle type as well.  Yes, you would have an extra thing sticking out of your laptop, but its a lot cheaper than replacing the motherboard.

Also, it seems like this is a problem that might happen agin so I would be hesitant on getting a new motherboard.

I had my buddy put a minipci network card in his and he doesn't miss the broken wired lan card at all.

Otherwise you will be looking at motherboard replacement.
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by:ddrdan
ID: 13970685
"It seems to "break" when it's here at the office though"
 Chain the new one to the desk for a week and see what happens ..... lol

Seriously, warn him not to plug in his NIC at home with the laptop running. Phone line voltage (ASDL) can vary dramatically, based on the line battery location, when plugging into an ADSL "offline" connection with the laptop running. If he lives in a large apartment building it could be even worse.

For around $45 he can buy a surge protector with a CAT5 plug to use at home just to be sure.
http://www.compusa.com/products/product_info.asp?product_code=304216&pfp=XSELLPRODAUTO&xsfrom=304215&xsdesc=11%2DOutlet+Performance+SurgeArrest+Surge+Protector%2C+Phone+%2F+Coax
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by:nobus
ID: 13975376
he can have his phone company check the line too...
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by:PlaceIT
ID: 14045033
All very goood recommendations.  Wish I could accept many of these responses.  We haven't had a problem since we put the laptop on a hub.  

DDRdan's recommendation is also a good one.  I will definitely look into that product.
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