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Interference (probably high frequency) in neutral line. Pls help.

Posted by bagho (My Page) on
Sun, Aug 18, 13 at 22:02

Hello everybody! I'm Tiger from India. :)

Recently, I'm finding that my laptop touchpad goes awry and erratic whenever I plug the laptop adapter to the wall socket. At first, I suspected the adapter itself, but when I started my workaround to find out the real fault, here are the conclusions I've got.

1. It's not the adapter. Even if the wall socket switch is turned off and the adapter is plugged in, the interference happens.

2. The laptop with its adapter works fine everywhere, except my home.

3. Neutal-Grounding Voltage = 2.4 V with light load, 5V with high household load.

4. I unplugged all SMPS based equipments, still the problem continues.

5. Even if I short the neutral and ground beyond the RCCB, the problem continues.

6. I connected one wire from the laptop adapter into each hole of the socket for testing. Whenever I put the wire in the neutral hole, the touchpad went erratic.

7. Surprisingly, my colleague's laptop (of other brand) exhibited the same problem in my house, although to a lesser extent!

All local electricians failed to identify the problem. Where is this possibly high-frequency interference coming from?

All these happening with no Air Con/Refrigerator/Compressor running.

Could you kindly help me out? It's becoming impossible to use laptops in my house.


Follow-Up Postings:

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RE: Interference (probably high frequency) in neutral line. Pls h

Have you tried a surge protector?


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RE: Interference (probably high frequency) in neutral line. Pls h

Have you tried a surge protector?


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RE: Interference (probably high frequency) in neutral line. Pls h

Have you tried using your laptop at a neighbor's house to see if the problem is not restricted to yours?
Is there something transmitting a high wattage radio frequency signal in your area, or perhaps a high voltage power line close by where an insulator is breaking down or there is a high resistance short?
Just spitballing here.


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RE: Interference (probably high frequency) in neutral line. Pls h

Thank you for the replies, Auger and randy.

Yes, I've tried a MOV based surge protector. The same problem.

Randy, the laptop works fine everywhere, except my house's power outlet.

Yea, there is a 33KV substation, just 50m away from my house. Could that be a problem?

Thank you.


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RE: Interference (probably high frequency) in neutral line. Pls h

Have you called the power company, they can check the transformer that feed your house for free since it's theirs. You can also try to locate an o-scope to check the voltage coming out. There might be a signal you can see coming from somewhere. I remember 10-15 years ago, many companies started making systems that used the wires in the house to send data between devices.

Have you tried all the outlets? I'm assuming you have, but just double checking.

I'd also verify your ground integrity. Tighten screws and what not.

Here is a link that might be useful: FCC Interference source.


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RE: Interference (probably high frequency) in neutral line. Pls h

Thank you very much for the reply, Eline. :) I'll do it. I think I need an oscilloscope and inform the power company if I find any HF Interference. I shall keep you updated. :)

Thanks.


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