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Old 21st November 2007, 01:58 AM   #1
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Thumbs down AC on chassis!

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!
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Old 21st November 2007, 02:59 AM   #2
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What was the reference of the measurement.
10M insulation resistance (e.g. of a transformer) measured with a DMM of 10M input resistance will read half the voltage.

Gajanan Phadte
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Old 21st November 2007, 03:14 AM   #3
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I just mesure the chassis from the DVD player to ground and got 48v AC!
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Old 21st November 2007, 04:00 AM   #4
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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?
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Old 21st November 2007, 04:18 AM   #5
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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.
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Old 21st November 2007, 04:23 AM   #6
Zen Mod is offline Zen Mod  Serbia
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just ground chassis of DVD with dedicated wire ;

if it dies from that - then buy new one .
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Old 21st November 2007, 04:27 AM   #7
sandyK is offline sandyK  Australia
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Default 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
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Old 21st November 2007, 04:29 AM   #8
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But,where should I get the ground from?.if the power cord is just two plugs.is it safe to do it like that?something is wrong for sure!.
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Old 21st November 2007, 04:36 AM   #9
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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.
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Old 21st November 2007, 04:36 AM   #10
sandyK is offline sandyK  Australia
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Default AC on Chassis

DV563A SMPS - This is typical. THe AC voltage is at very low current and not dangerous. It may however cause a small hum on it's input of an earthed preamp/poweramp.

SandyK


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