Getting shocked by a laptop...is this normal?

spodosaurus wrote:
spodosaurus wrote:
Rod Speed wrote:
spodosaurus wrote
Rod Speed wrote
spodosaurus wrote

I was using a laptop that has s-video out. The s-video cable was
plugged into the TV. The laptop was plugged into mains power via its
adapter. When I went to plug the s-video into the back of the laptop
my hand (holding the s-video adapter end bit) brushed against a
serial port on the back and I got zapped. I tried without the
s-video in hand, no zap, and without touching the serial port, no
zap. Is this normal? I relaise there may be current coming from the
TV down the s-video cable and went through my hand into the serial
port, or perhaps the other way. I cannot imagine that this is a
normal state of affairs, so I thought I'd ask the experts here.

It isnt unusual to get a tingle off a double insulated mains
powered device like a TV when the other side is grounded.

Nothing to worry about, its just the capacitor effect.

Thanks Rod. Given that it's making a high pitched noise, reminiscent
of a modem or the sound effects for computers in 1980s B-grade
movies, and the manufacturer is going to be sending someone around to
fix the laptop screen hinge as well as replace the motherboard (to
stop the noise...it sounds more like it's coming from the miniPCI
card or the hard drive, but not at all like a bearing noise) I
thought I should check and see.

Yeah, understandable with that noise there too.

The short story with the tingle, if that is all it is, is that there is
nothing much you can do about it with the svideo connection.
With the antenna connection you can use a balun, but its more
complicated with the svideo connection. Dont worry about it.

If something else needed to be replaced to fix the zapping and the
noise, I'd rather they do that first instead of after openning the
laptop two or three times and replacing random parts.

Yeah, and if the monkey isnt aware of the tingle problem with
double insulated devices like TVs, it wont help at all anyway.

Any ideas about what could be causing the sound?

Noises are notoriously hard to describe. Nothing springs to
mind, but that might be different if you could record the sound.

It might be the hard drive recalibrating, and that is real bad news.

It might just be a fan bearing, tho that seems unlikely given
that you say that it doesnt sound like a bearing noise.

You can sometimes get a fault in the audio system that produces noises.


It's intermittent, usually and I can hear the hard drive making its
normal grumbling noises in bursts when it's happening. The last time
it was doing it (last night) I was watching a full screen power point
slideshow for work training. When I would switch between slides, both
the grumbling and the high pitched noise would stop.

Ari


PS- Hitachi drive tool, after a full scan, says the drive is okay. It's
bloody hot though: the bottom of the laptop is hot to the touch under
the drive panel.

Ari


Okay, replacing the motherboard did nothing, but it did give the tech
some time to remove other cards and recreate the noise (we even got a
new type of high pitched noise this time, we both thought it was coming
from the other's mobile phone). Looks to be the hard drive, getting
replaced tomorrow. I never like getting 'new' things at the end of a
warranty, especially motherboards. MI think my old board was fine, and
if it was it probably would have remained fine for a while. However, a
new board that dies a month out of warranty is very agitating
....especially with laptops and the cost of replacement parts!

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spodosaurus wrote:
spodosaurus wrote:
spodosaurus wrote:
Rod Speed wrote:
spodosaurus wrote
Rod Speed wrote
spodosaurus wrote

I was using a laptop that has s-video out. The s-video cable was
plugged into the TV. The laptop was plugged into mains power
via its adapter. When I went to plug the s-video into the back
of the laptop my hand (holding the s-video adapter end bit)
brushed against a serial port on the back and I got zapped. I
tried without the s-video in hand, no zap, and without touching
the serial port, no zap. Is this normal? I relaise there may be
current coming from the TV down the s-video cable and went
through my hand into the serial port, or perhaps the other way.
I cannot imagine that this is a normal state of affairs, so I
thought I'd ask the experts here.

It isnt unusual to get a tingle off a double insulated mains
powered device like a TV when the other side is grounded.

Nothing to worry about, its just the capacitor effect.

Thanks Rod. Given that it's making a high pitched noise,
reminiscent of a modem or the sound effects for computers in
1980s B-grade movies, and the manufacturer is going to be sending
someone around to fix the laptop screen hinge as well as replace
the motherboard (to stop the noise...it sounds more like it's
coming from the miniPCI card or the hard drive, but not at all
like a bearing noise) I thought I should check and see.

Yeah, understandable with that noise there too.

The short story with the tingle, if that is all it is, is that
there is nothing much you can do about it with the svideo
connection. With the antenna connection you can use a balun, but its more
complicated with the svideo connection. Dont worry about it.

If something else needed to be replaced to fix the zapping and the
noise, I'd rather they do that first instead of after openning the
laptop two or three times and replacing random parts.

Yeah, and if the monkey isnt aware of the tingle problem with
double insulated devices like TVs, it wont help at all anyway.

Any ideas about what could be causing the sound?

Noises are notoriously hard to describe. Nothing springs to
mind, but that might be different if you could record the sound.

It might be the hard drive recalibrating, and that is real bad
news. It might just be a fan bearing, tho that seems unlikely given
that you say that it doesnt sound like a bearing noise.

You can sometimes get a fault in the audio system that produces
noises.

It's intermittent, usually and I can hear the hard drive making its
normal grumbling noises in bursts when it's happening. The last time
it was doing it (last night) I was watching a full screen power
point slideshow for work training. When I would switch between
slides, both the grumbling and the high pitched noise would stop.

PS- Hitachi drive tool, after a full scan, says the drive is okay.
It's bloody hot though: the bottom of the laptop is hot to the touch
under the drive panel.

Okay, replacing the motherboard did nothing, but it did give the tech
some time to remove other cards and recreate the noise (we even got a
new type of high pitched noise this time, we both thought it was
coming from the other's mobile phone). Looks to be the hard drive,
getting replaced tomorrow.

Yeah, that's certainly possible.

I never like getting 'new' things at the end of a warranty, especially motherboards. MI think my
old board was fine, and if it was it probably would have remained fine for a while.

Yeah, it shouldnt die. Understandable that he didnt want to
swap the original back in tho time wise. I normally do that myself.

However, a new board that dies a month out of warranty is very
agitating ...especially with laptops and the cost of replacement parts!

Yeah, that's the main downside with laptops.