Being electrocuted by my telly - Stumped

ChristopherP

ChristopherP

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Right then folks. Who here knows about electrics?

To cut a long story short, our 46" Samsung telly in the kitchen, of 2012 vintage makes my hand go all tingly when I touch the bezel or the stand (both are metal). Not a massive shock or anything like that, but enough to make you not want to keep your hand there for any length of time. Enough for my Mrs to pull her hand away and shake it.

Not good, I thought. Especially with a kid in the house, so called Curry's who in turn sent out Samsung to our house to check it over.

Couldn't find anything wrong with it, the guy couldn't feel what we felt, and prodded it with a multimeter and did checks and didn't;t register anything.

This evening I go to move it, and get the same sensation.

I get my multimeter out and (I'm not an expert - not sure I'm using it right) get a consistent reading of around 0.5v AC. Doesn't sound like much, but I'm not sure it's right all the same? The Samsung repair chap said that it wasn't possible for any voltage to leak through into the stand or bezel as it's all fully insulated by plastic.

I'm stumped. Thoughts? Stupid question, but could the metal parts be picking up electric from anywhere else?

IMG_8303.jpg
 
...Update.

I've narrowed it down to coming through the HDMI cable from my Sky Box.

Unplug either the HDMI cable or Power Lead from the Sky Box and the voltage goes away.

But how is it getting from the HDMI port into the (insulated) bezel and stand?!
 
Hiya Chris, Try touching black probe to an earth and then red to plastic. The plastic may have been sprayed with a metallised paint and maybe conducting slightly. HDMI only carries about 5v, not sure on it's current but if its causing a problem try using a different hdmi port and first. Chances are it is just ESD which would suggest maybe a bad earth?
 
Just found this

"LCD displays, membrane panels, and tactile rubber keypads can be very good at preventing ESD if a few basic precautions are taken. Although their surfaces are ESD-proof at least to 15kV, they can have problems at their edges. ESD sparks can track along the dirt on their insulating surfaces, and go around their edges to reach vulnerable internal tracks.

LCDs often dealt with this problem by using large bezels which prevented fingers from getting too close to their edges. Insulating sealant and similar materials are now more likely to be used these days. Another method is to surround the LCD panel with a metal bracket that ‘catches’ the spark before it gets to any sensitive parts, but then something has to be done to remove the charge from the metal surround without it discharging itself into some sensitive part."
 
TriplexDread said:
Hiya Chris, Try touching black probe to an earth and then red to plastic. The plastic may have been sprayed with a metallised paint and maybe conducting slightly. HDMI only carries about 5v, not sure on it's current but if its causing a problem try using a different hdmi port and first. Chances are it is just ESD which would suggest maybe a bad earth?
Click to expand...

I think the stand and the bezel are proper metal rather than sprayed plastic, but do you mean touch the red probe against either of these? What would be a good earth that I can touch near the TV?

(Sorry, I know very little about electrics)
 
Anything but the actual chassis. The screw on the plug socket would suffice usually

Don't do anything if not sure mate. Just leave it and don't touch the tv again ;)
 
If, after getting the shock, you touch the stand again do you get another shock? If not it may be static that has built up on you that then discharges when you touch metal. I sometimes get that same thing if I get out of the car and touch the metal of the door. Certain types of clothing rubbing on certain fabrics can produce static.

Just a thought. :)
 
You certainly have a puzzle mate.

I had a strange do with lectrikery once. In Birmingham at my girlfriends we would often walk around barefooted in the house. Every now and again when using the light switch at the top of the stairs we would get a small shock.
We changed the switch, checked out the wiring and were stumped. Quite by chance I was altering the heating pipes and had to lift the floorboards in the upper hallway below the afor mentioned light switch. There I found that one of the nails holding the floorboards in place had nicked the electric cable powering the switch. Problem solved.
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Clutching at straws here but if both devices (TV & Skybox) are earthed, try disconnecting one of the earths in the mains plug.

Or it may be worth buying an isolation transformer and trying each device with it to see if that cures it. The isolation transformer is simply that, 240v to 240v but making the connection connected by air between windings.
 
floppybootstomp said:
Clutching at straws here but if both devices (TV & Skybox) are earthed, try disconnecting one of the earths in the mains plug.

Or it may be worth buying an isolation transformer and trying each device with it to see if that cures it. The isolation transformer is simply that, 240v to 240v but making the connection connected by air between windings.
Click to expand...

I have to say flops that most of that went over my head! I don't really understand much about electrics.

I called the company that Samsung sent out back, and said that the AC readings on my multimeter were useless as the TV runs on DC and I'd get similar readings touching the probes against my hands. I couldn't help but wonder why then the AC readings increased when the Sky box was plugged in, but he seemed pretty adamant that it was impossible for any current to get from the HDMI port to the stand as it's all isolated with plastic.

I can't get any readings on the multimeter when I turn it to DC mode.

He says it's entirely safe. I'll just try not to touch it...

*scratches head*
 
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