Does your C-9000 do this?

[cam94z28]

It's been pretty well accepted that the C-9000 makes a high pitched noise while charging. Mine makes a second long high pitched squeal, with a second of silence in between. Except for slot 4. Slot #4 is inaudible, no matter what mah I'm charging at, while the other 3 slots squeal away with their moderately annoying noise. If I'm charging in slot #4 by itself, I can only hear it if i put my ear right up to the unit.

Does anyone else's do this?

If the other 3 slots could be as quiet as slot #4, I'd enjoy this charger a lot more. Can't even sleep with the other 3 slots going and the charger across the room. Slot 3 seems to be a tiny bit quieter than 4, but the closer you get to slot 1, the louder the noise.

Is this just the nature of how this type of charger works, or is mine just an oddball?

Would dust, or oils from fingers on the contacts cause the noise. Would something like deoxit quiet it down?

I find it wierd that I've read just as many reports of no audible noise, as I have of loud noise coming from the unit. Maybe it depends how sensitive your ears are.

 

[VidPro]

its the nature of the dc dc curcuits, and the switching curcuits and stuff.
if (things like) the ferrous center of a induction coil is loose, stuff like that.
it used to be (way back before i can remember 🙂 everything Hummed, tubes, transformers, all the stuff you pluged into the wall.

now its replaced by faster "switching" and pulsing, before the loose laminated plates of a transformer would increase the Humm, now loose parts can increase the inevetably of the whine instead. all this magnetic induction and transferring and transduction is still occuring like it has for 40 years, its just occuring at 1,000-10,000Htz instead of 60 and 120htz.

even the AC converting transformers are changing to "switching" type power supplies. so tinitus is going to be happening all over 🙂

i bet it can be dampened, because some things doing the same level of work, will be much louder than others. transferring the vibration to PCB boards that are becomming piazio speakers for the noise, in "as little as it takes" plastic housings.

you sure cant put a pillow over it, but you can stuff it out in the garage 🙂

i really think it is stuff like that that causes intermittint high pitched ear ringing in my crusty old ears, because when i depart civilisation (backpacking) it doesnt happen out there.

 

[VidPro]

as an example of complete dampening, i have some dc dc curcuits that were put in hunks of black hard pastic stuff for heat syncing and "potting", you can stick them right up to your ear and not hear anything.

some things i have worked on, i have potted completely into J&B weld, and they dont make any noise i can hear either.
i dont know the exact makup of the curcuits, so i am not positive, but i bet dampening is possible, by freezing everything in place that can rattle out a sound wave.

problem is most of this stuff wouldnt survive a day without some sort of good heat conductive potting, with fins. not gonna happen becuase shipping costs would take 50c of profit.

 

[VidPro]

here we go, No dissasemble 🙂
http://www.candlepowerforums.com/vb/showthread.php?t=146310&highlight=C-9000
the coils ARE stuck to the board with some sort of glue or silicoln or something , which should reduce any sounds from them

i was trying to find an old motherboard too, so i could see that they sometimes put a glob of something down the side of some parts to stabalise them.

 

[macdude22]

My C9000 makes a pulsing squeal, or so my wife says. I can't hear it at all. But I swear she can hear it a room away. Coincidentally my 808M makes a pulsing click that I hear quite clearly but my wife can't hear it at all. It's fascinating how we both seem to have specific frequencies that our ears can't detect. I'm fairly certain it's normal, the charging circuit switching or something.

 

[benjamin921]

My wife is about ready to throw it out the window with the pulse sound it makes 😱

 

[TorchBoy]

The worst noise from mine is from the plug pack/wall wart. If I press down on the top/back of it (on the large face, I mean), the very faint squeal vanishes. But the charger does other special things in its operation, such as discharging at 1180+ mA on slot 1. :shakehead

BTW, the symbol for hertz is Hz.

 

[cam94z28]

The worst noise from mine is from the plug pack/wall wart. If I press down on the top/back of it (on the large face, I mean), the very faint squeal vanishes. But the charger does other special things in its operation, such as discharging at 1180+ mA on slot 1. :shakehead

BTW, the symbol for hertz is Hz.

I havent seen the higher discharge rate on mine, and my power supply is totally silent. But slot 1 does seem to have a habit of reading lower than the other 3 for the final discharge capacity.

 

[TorchBoy]

Mine's a heat-related issue, slot 1 only. It seems like quite a few people have commented that their slot 1 reads lower. Well, a handful of people at least.