HI yea my n70 was working fine when i bought it. for 2 weeks i didn't use it. Now when i opened it as soon as the light in the cellphone turns on i can hear a weird noise coming from the n70 but im not sure what is it and as sooon as the light turns off it stops. the noise is low when i bring the phone close to the ear to talk to some one then i can hear it. any suggestions wat should i do should i replace the battery or anything else?
ANother thing i got the cell from middle east and i use to charge it with a different charger. when i came back to canada i bought a different charger is this happeneing cuz of the charger ?
It's not the charger. My old 3230 had the same problem and the noise came out from the keypad. I don't have a clue about which might be the cause.
Hey... dont worry about the noise... its ok, its just from the lights... and isnt damaging your phone, i hear it to.. sent me crazy at first.. but when i relized what it was its cool... i get the problem alot actualy, i hear a noise from my gauges in the car when i turn the lights on lol.. its your ears... you could probably get a older person to try and listen and not hear it lol... but yea dont worry
The sound is disturbing, because it will be recorded when taking videoclips. The problem is that it can't be stopped somehow.
Following discussion with my mate, a science teacher, here's a possible tech answer to the little man playing the bagpipes in your phone 😊 ,
The most likely culprit is a square wave oscillator driving the LED lights that illuminate the keys. Generally speaking LED lights are not fed a constant current; they are switched rapidly to save power. Persistence of vision (POV) means that if the frequency is greater than about 50Hz, then we won�t notice it.
In reality they are often switched at much higher frequencies than this but the higher frequencies are derived as harmonics of a lower frequency oscillator. It is quite possible that this will be in the upper reaches of our audio frequency range (18kHz+). This lower frequency oscillator can be used to drive a pulse width modulated (PWM) signal to control the dimming of the LED; another source of possible interference.
It would not seem unreasonable to suppose that lighting and audio tracks run close by (and unshielded) on the printed circuit board. The interference would most likely be due to capacitive coupling between adjacent PCB tracks rather than radio frequency interference (if the LED driver is indeed the problem). Any adjacent conductors at different potentials will act as a capacitor which will then allow a current to flow which will be proportional to the frequency of the signal.
The bagpipe effect could be due to the extra loading on the LED driver circuit causing variations in its frequency or a harmonic effects due to �reflections� in the overall system causing standing waves. The changing pitch would be nodes and anti-nodes, usually these would be fixed but in an unstable system you can get some very weird oscillations. Square waves are just a collection of a lot of sinewaves of varying frequencies as a fourier analysis will reveal, this gives a lot of scope for weird noises. Alternatively you could be hearing the PWM output as it adjusts the LED intensity.
As often happens, the design probably worked great in the lab, but then there were a few tweaks on the way to the final production version and some unforseen interference crept in. The shielding on mobile phones is crap anyway, some of them piss out more EM radiation from the speaker/keyboard than the actual antenna, so it�s not surprising that they make silly noises!
PS, the smallest known bagpipe player was Scotty McTadger from the Isle of Kallyhoonadoon. At 14.7mm tall he would still be a bit large for a modern mobile phone, so I suspect a real bagpiper inside the phone is unlikely... :tongue:
Interesting "tech" point of view:icon14:
It is true that the LEDs are controlled in dimming with PWM, this can interfere with the audio, but the sound doesn't come from the earpiece or loudspeaker, it cames just beneath the keypad. It might be a coil not stiff enough and it vibrates on 50 Hz.
ratza wrote:It is true that the LEDs are controlled in dimming with PWM, this can interfere with the audio, but the sound doesn't come from the earpiece or loudspeaker, it cames just beneath the keypad. It might be a coil not stiff enough and it vibrates on 50 Hz.
Did you find any solution to this problem(It's driving me crazy) ?
Nope. I didn't have the time to open up the phone to see what needs to be "tuned". I think opening it is the only solution.