Just before I went away on holiday for a few weeks my daughter broke the charger on her laptop. Fortunately my laptop has the same charger as hers but it was a bit of a pain because we ended up like a couple of divers buddy breathing. "Quick it is my turn for the charger!" would come the call and we would swap the cable from hers to mine or vice versa.
On returning home a quick search on eBay revealed loads for sale. Some of them are obviously cheap Chinese copies while others are said to be genuine. We opted for one that was said to be genuine, from a UK supplier and it arrived next day in the post. It seemed to work fine when I tried it and it gave the same output voltage as mine under load.
All was happy in the household until the weekend and Emily was using her laptop while I was on 80 metres. As soon as she turned on the charger the noise level shot from S3 to S9 + 60dB. A quick check on 60 & 40 metres revealed that they too had S9 of noise from the charger. There was no problem at higher frequencies or on 160 metres.
So it is back to borrowing mine for a while until we resolve the problem with the faulty charger. The question is I suppose is if the problem is a one off dodgy item or an inherent fault. All of the chargers, both the replacement copies and the originals are made in China. The labels say they are made by Delta Electronics Inc., but I suspect the so called genuine replacement is either a poor quality copy or maybe has been bought as a batch of rejects from Delta, which is why they are so cheap.
Rather than risk buying another duff charger I think some investigatory surgery is required on both the noisy and broken chargers. I just hope they are not embedded in the usual resin as it should be easy to make one good one out of the two.