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Old 11th September 2011, 00:05   #1
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Default Strange Phenomenon: Power Adapters gone bad kept near CRT TV

I have observed strange phenomenon today at my home. I kept two power adapters near my CRT TV. Both of them were 230V AC Adapters.

One belongs to NBox Media Player. It had output voltage of 5V and max current 1500mA. It is high quality built and working fine when I kept it last there.

Second power adapter was for Mitashi Game console of my kid. It was having rating of 9V and 850mA of current. It is also high quality build and working fine when I kept it last.

Today, I wanted to use my NBox media player for playing some video. To my surprise media player was not working. I have multimeter also. When I checked output voltage, sometimes, it was showing .30 volt and sometimes nothing. I tried to test it in different power points but without success. I said OK, looks like it has gone bad.

Mitashi adapter was also kept nearby. Thought lets measure its output voltage. To my surprise, it was also not working. Sometimes, it was showing .1 V as output.

As per my knowledge both adapters were

1. Working, when I used it last time 8 - 9 months back.
2. Both of them are solid and quality build.
3. Nobody touches these things apart from me at home.
4. Both of them kept neatly.

Is it mere coincidence that both adapters gone bad at the same time?

Or, is it gone bad as both of them kept in the vicinity of big CRT TV due to some interference or magnetic field nearby? Any scientific explanation?

Please help me understand this strange phenomena.
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Old 11th September 2011, 00:14   #2
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Default Re: Strange Phenomenon: Power Adapters gone bad kept near CRT TV

Not sure about Mitashi, but NBox adapter is pretty bad. I have NBox and this unit is made in typical "You quot price, we quote quality" manufacturing arrangement.

Just take it to an electronics parts store, you can get a replacement for 200 Rs or so.
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Old 11th September 2011, 09:25   #3
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Default Re: Strange Phenomenon: Power Adapters gone bad kept near CRT TV

Were these 2 adapters on the same power outlet?

Was the CRT also on the same power outlet. Sometimes During a power surge, inductive energyfrom the CRT is pushed back into the power lines and might have caused a surge into the adapter.
If the adapters are typical transformer based then a power surge can short the transformer core and wire .

Solid state adapters are far better for handling these power surges.
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Old 11th September 2011, 18:05   #4
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Default Re: Strange Phenomenon: Power Adapters gone bad kept near CRT TV

Inductive voltages (eg:- from the CRT's LoT - very high voltage) leaking/ causing elector magnetic fields, causing capacitors in the adapters to go bust?

Else, no reason to see varying current in output of adapters.
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Old 11th September 2011, 18:57   #5
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Default Re: Strange Phenomenon: Power Adapters gone bad kept near CRT TV

Now that they are bad and not worth getting repaired, why dont you pry them open and take a peek at what part failed in both? As you have a multimeter you can test diodes and capacitors of the rectifier. burnt transformer can be diagnosed by sight only. Maybe that might provide a lead in this case.
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Old 11th September 2011, 23:54   #6
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Default Re: Strange Phenomenon: Power Adapters gone bad kept near CRT TV

Quote:
Originally Posted by leadf00t View Post
Were these 2 adapters on the same power outlet?
Both of these adapters are not in use and kept just below CRT TV for 8 - 9 months. Not connected to power.


Quote:
Originally Posted by NetfreakBombay View Post
Not sure about Mitashi, but NBox adapter is pretty bad. I have NBox and this unit is made in typical "You quot price, we quote quality" manufacturing arrangement.
I had old Nokia classic charger, I compared the voltage of NBox adapter and Nokia charger were same only current rating was different. NBox adapter has same pin as of Nokia classic charger and when connected, NBox media player started working.

Quote:
Originally Posted by BaCkSeAtDrIVeR View Post
Inductive voltages (eg:- from the CRT's LoT - very high voltage) leaking/ causing elector magnetic fields, causing capacitors in the adapters to go bust?
I kept both the adapters. Would investigate soon. Today I was bit busy. It was really surprising for me that two adapters used last time without any problem gone bad together. I can open Mitashi adapter but do not have clue how to open NBox adapter.

Electronics engineer can comment on this statement: Capacitors can go bad if kept near high magnetic field.

Quote:
Originally Posted by dhawcash View Post
Now that they are bad and not worth getting repaired, why dont you pry them open and take a peek at what part failed in both? As you have a multimeter you can test diodes and capacitors of the rectifier. burnt transformer can be diagnosed by sight only. Maybe that might provide a lead in this case.
Yeah, I kept both the adapters with me and I will investigate. I had opened Mitashi adapter but couldn't test it properly. Only I can make out no output was coming but input going sufficiently as 240Volts. There is no mark of burning or smell.

I do not have clue how to open NBox adapter. It look like as solid Mobile charger.
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Old 12th September 2011, 15:51   #7
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Default Re: Strange Phenomenon: Power Adapters gone bad kept near CRT TV

err, i may sound lame, but could it be that the output terminals have corroded a bit in 8 months and the corrosion is not allowing current to flow? or maybe an internal wire break ( If you have kids at home maybe they pulled the wires- this would stretch and break the conductor inside and the wire would still look okay from the outside). to be sure just chop the wire at any place and try measuring voltage across the outputs hence uncovered.

PS:i have came across some adaptors which use iron as a conductor in the output wire instead of copper. this iron wire corroded and there was no current flow as a result

Last edited by dhawcash : 12th September 2011 at 15:54.
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