AC on chassis!

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Hi! the other day I had my DVD player(Pioneer Dv-563A) unplug (RCA input)from my Gainclone LM3875 but.and I was listen to TV using my Gainclone and I hear sometimes like static from speakers.I started checking for the source where it came from(took me like two hrs)and I finally found that the output(RCA) had 48 volts AC. I touched the from RCA to chassis of my cable box and starting to hear static.is this possible that a chassis can get 48 volts AC? the DVD is playing fine but the chassis has 48 volts AC.and the DVD is not too old(14 months).so now I have to buy a new DVD,Lucky me!:bigeyes:
 
Your chassis is floating (2 pin plug right) and you're measuring leakage current through DVM resistance (>10Mohm)

If you can find out why this current is flowing if you want to fix static. It could be something to do with the TV or cable connection or phases on the mains outlets.

Is it a problem when everything is plugged in?
 
Well,I have a Isotel-6 Ultra surge protector and my Gainclone,Tv,DVD,satellite receiver are connected to it.right now I unplugged the DVD from AC.the satellite receiver has two plugs(power cord) and I measured from chassis to ground and I do not get any voltage but,when I connect the DVD player and I measure from chassis to ground,I get 48v AC.My Gainclone has three plugs(one is ground).but,I am sure the DVD payer is danger to keep it plugged in(I have children).so that is why I have it unplugged and soon I will have to get a new one with no voltage on the chassis lol.:smash:
 
AC on Chassis

Guys
What you are seeing is normal from a pice of equipment using an SMPS PSU. On a 240V DVD Player STB etc, this figure can be as high as 120VAC. All of these SMPS powered devices have a special high voltage capacitor between the mains side and the "earth" of the player RCA sockets etc. You will get a "bite" when plugging in to an earthed preamp or power amplifier, whether switched on or not. I brought this up in the "Destroyer" thread a little while back.

SandyK
 
AC on Chassis Post #7
Guys
What you are seeing is normal from a piece of equipment using an SMPS PSU. On a 240V DVD Player STB etc, this figure can be as high as 120VAC. All of these SMPS powered devices have a special high voltage capacitor between the mains side and the "earth" of the player RCA sockets etc. You will get a "bite" when plugging in to an earthed preamp or power amplifier, whether switched on or not. I brought this up in the "Destroyer" thread a little while back.

SandyK.


Well Sandyk. if this is "normal" to get 48v AC,this is the first time that I hear a"chassis" getting a voltage!who ever design this piece of junk,should be shot!. that is for sure.:smash:
 
AC on chassis

Guys
Sorry, but we will all have to learn to live with it !
SMPS PSUs have been mandated by EU, as well as the state of California, to replace linear PSUs. It will be world wide soon, like it or not !
Blame the "greenies" !

SandyK

BTW, My Oppo DV981HD DVD-A/SACD player , which works on 240VAC, readsa approx 82VAC to earth.
 
AC on Chassis

lanchile07

Lots of luck. I doubt that you will be readily able to buy a DVD player etc that isn't using an SMPS supply. All the linear PSU ones will be phased out, if they haven't been already. The problem even extends now to headphone amplifiers, where a talented English designer had to start using SMPS plug packs, and had a few similar reports to yours. Sometimes you could feel a "vibration" if you rubbed your fingers across the unit's metal case.
SandyK
 
AC on chassis

lanchile07

No damage will result. As I said previously, it is due to the very
small current flowing through that capacitor,which I highlighted in red, on the attachment. You may feel a tingle when plugging in to an earthed preamp etc, but it is not dangerous. Some linear PSU devices also have a small AC voltage present between them and earth. My old S-VHS recorder had >3VAC to earth. I used to notice a "bite" when plugging in leads or antenna.

SandyK
 
AC on chassis

lanchile07
As I said previously, it is at such a low current that it is harmless.
SMPS supplies have been mandated by legislation to help reduce power consumption, and thus, greenhouse gas emissions.
These supplies will also soon all be intelligent, and adjust themselves to the actual current demands. This will make all of these players ,STBs etc ,much more energy efficient.
It's just like some countries have recently legislated to ban incandescent lighting in favour of Energy Saver lamps.
I don't particularly like them either, but that's what we all have to look forward to.
SandyK
 
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