Hello,
I bought Benq WIT (E-reading) lamp, price around 230 euro.

What is happening is that adapter it comes with 12V, 2A, 24W (which looks pretty cheap junk) is producing some strange sounds ... kind of pulsating squeaking sound / buzzing. Its not possible to hear it while radio in the room is on and so on ... but while room is quite during the reading i can hear it.

Any idea what can produce such a sound? Isnt it a better idea to buy a proper mean well PSU and replace junk that comes with a lamp?


Thanks!

 

Electrolytic capacitors may degrade over time. This can cause buzzing sounds.

 

@liaifat85 it's brand new lamp.

Does it mean it's faulty? Or low quality capacitors?

 

There are two main sources of acoustic noise from electronic assemblies. The first is poor quality magnetic devices such as transformers and inductors, which includes filter chokes and switcher transformers. The other, amazing, source of some noise is micro-phonic ceramic capacitors. Some of them act as piezo-electric transducers because the ceramic core IS piezo-electric material.
Replacement, or embedding the material in vibration damping silicone may be a cure.

 

@liaifat85 it's brand new lamp.

Does it mean it's faulty? Or low quality capacitors?

Oh! If that's the case I think you must claim a replacement.

 

So It should be completely quiete psu?

Thanks

 

MOST lamps are totally quiet in my experience. BUT if the seller does not claim that the lamp is quiet, then the noise is probably within the specification.
Of course it is likely that there is a big difference between my definition of acceptable quality and the seller's definition of adequate quality. So, if there is any warranty provided, I suggest operating the lamp constantly for at least a week, to see if there is a failure within the warranty period.
If no warranty was expressed or claimed, and the lamp does provide the claimed illumination, you have what you have, no choice. Good Luck!!

 

@MisterBill2
thats what seller (benq) says:
A slight buzzing sound from the power supply unit (PSU) can sometimes occur due to electrical components operating under normal conditions. This is usually not a sign of a defect and does not affect the lamp's performance or safety. Thanks again.



So, just wondering if i can replace that shitty chinese PSU with Meanwell for example?

thanks

 

Another supply with adequate ratings should work quite well, although that is a rather expensive solution. Depending on where you are in the world, there may be local resale shops that would sell a supply with those ratings for much less than the price of a new one. So that could be another option. The only difficulty would be transplanting the DC output cable to the replacement supply in a correct, safe, and attractive manner.

It might also be possible to either open the case of the noisy supply and apply dampening material, OR, make a small (1/16 inch diameter)hole in the case and squirt in some of that expanding insulating foam.