Is this a fault?

[Glenn Pure]

While re-arranging bits of my stereo last night, I got an unpleasant
tingle on my hand from the end of an audio (line out) plug from my
VCR. The VCR is a Samsung hifi unit and just over a year old.

It turns out that current was flowing from the VCR line out through me
to the earthed chassis of the amplifier. I measured just over 80 volts
with my (high input impedance) DMM. Both the signal ground (shield)
and the signal output pin from the VCR were at this level. I shorted
the VCR shield to my amplifier chassis through the DMM on amps range
and measured 16 microamps.

Is this a problem or 'normal'. I note the VCR appears to be double
insulated as it has no earth pin on its power plug (unlike my old NAD
amplifier).

I'd like some advice before I think about going to the service ageny
or Samsung

Cheers
Glenn

 

[Phil Allison]

"Glenn Pure" <Glenn.Pure*delete_this_for_reply*@pcug.org.au> wrote in
message news:3f5aabb0.4232999@newshost.pcug.org.au...

While re-arranging bits of my stereo last night, I got an unpleasant
tingle on my hand from the end of an audio (line out) plug from my
VCR. The VCR is a Samsung hifi unit and just over a year old.

It turns out that current was flowing from the VCR line out through me
to the earthed chassis of the amplifier. I measured just over 80 volts
with my (high input impedance) DMM. Both the signal ground (shield)
and the signal output pin from the VCR were at this level. I shorted
e VCR shield to my amplifier chassis through the DMM on amps range
and measured 16 microamps.

Is this a problem or 'normal'. I note the VCR appears to be double
insulated as it has no earth pin on its power plug (unlike my old NAD
amplifier).

I'd like some advice before I think about going to the service ageny
or Samsung

** Completely normal - it's due to stray capacitance to chassis in the
PSU.

16 uA leakage is very low actually, the current may be mostly high
frequency and did not read on your meter - try a CRO.



........... Phil

 

[Glenn Pure]

Thanks... also to Phil

As soon as I saw it, I decided it would be prudent to remove my
amplifier power plug to to avoid the type of damage you mentioned. A
bit of a trap for the unwary.

I now have a noisy hum (presumably an earth loop) to deal with from
connecting my new DVD via the VCR.

Cheers
Glenn

Peter_purple <purple@iinet.net.au> wrote:

I have this on my VCR too, though might as high as 116v
and it was enough to damage the aux input on the VCR as it connected
before the ground outside of the rca connector did

purple_engine

Glenn Pure wrote:

While re-arranging bits of my stereo last night, I got an unpleasant
tingle on my hand from the end of an audio (line out) plug from my
VCR. The VCR is a Samsung hifi unit and just over a year old.

It turns out that current was flowing from the VCR line out through me
to the earthed chassis of the amplifier. I measured just over 80 volts
with my (high input impedance) DMM. Both the signal ground (shield)
and the signal output pin from the VCR were at this level. I shorted
the VCR shield to my amplifier chassis through the DMM on amps range
and measured 16 microamps.

Is this a problem or 'normal'. I note the VCR appears to be double
insulated as it has no earth pin on its power plug (unlike my old NAD
amplifier).

I'd like some advice before I think about going to the service ageny
or Samsung

Cheers
Glenn

 

[Phil Allison]

"Glenn Pure" <Glenn.Pure*delete_this_for_reply*@pcug.org.au> wrote in
message news:3f5b0ff8.322749@newshost.pcug.org.au...

Thanks... also to Phil

As soon as I saw it, I decided it would be prudent to remove my
amplifier power plug to to avoid the type of damage you mentioned. A
bit of a trap for the unwary.

I now have a noisy hum (presumably an earth loop) to deal with from
connecting my new DVD via the VCR.

** An antenna isolator is probably needed.




.......... Phil

 

[Peter_purple]

I have this on my VCR too, though might as high as 116v
and it was enough to damage the aux input on the VCR as it connected
before the ground outside of the rca connector did

purple_engine

Glenn Pure wrote:

While re-arranging bits of my stereo last night, I got an unpleasant
tingle on my hand from the end of an audio (line out) plug from my
VCR. The VCR is a Samsung hifi unit and just over a year old.

It turns out that current was flowing from the VCR line out through me
to the earthed chassis of the amplifier. I measured just over 80 volts
with my (high input impedance) DMM. Both the signal ground (shield)
and the signal output pin from the VCR were at this level. I shorted
the VCR shield to my amplifier chassis through the DMM on amps range
and measured 16 microamps.

Is this a problem or 'normal'. I note the VCR appears to be double
insulated as it has no earth pin on its power plug (unlike my old NAD
amplifier).

I'd like some advice before I think about going to the service ageny
or Samsung

Cheers
Glenn

 

[Bob M]

"Phil Allison" <philallison@optusnet.com.au> wrote in message news:<3f5b21e2$0$6526$afc38c87@news.optusnet.com.au>...

"Glenn Pure" <Glenn.Pure*delete_this_for_reply*@pcug.org.au> wrote in
message news:3f5b0ff8.322749@newshost.pcug.org.au...
Thanks... also to Phil

As soon as I saw it, I decided it would be prudent to remove my
amplifier power plug to to avoid the type of damage you mentioned. A
bit of a trap for the unwary.

I now have a noisy hum (presumably an earth loop) to deal with from
connecting my new DVD via the VCR.



** An antenna isolator is probably needed.




......... Phil

Something else to be aware of. If your VCR is connected to a Cable
Company feed, you may be seeing the 60 VAC they feed down the line to
power the line amplifiers they use. The line tapping attenuator they
use to feed your house is supposed to block this but they don't always
work (shorted cap). When I was younger, I got zapped by the cable feed
to my home so I called the cable company. They came out and replaced
the tap. If you have a CRO, take a look at the voltage. The power
supplies the cable companies normally use output a square wave 50 or
60 Hz (country specific) signal.

Cheer from Canada

Bob Morgcoh