[SOLVED] Sony handycam charging

[Peter5510]

Hi all,
I have this Sony handycam.

I am using it for playback and transfer DV file to PC. Since the battery is not long holding charge, I have to plug to charger all the time. At the back of LCD panel is metal surface. Whenever I run my finger on the metal surface, I can feel vibration. When turn off the charger, I don't feel the vibration. Here are my questions.
1. Is there a leakage?
2. What causes it?

For those who know handycam, this unit has a white LCD screen when power on. The touch screen still working. Any tip on how to fix is much appreciated.

Thanks in advance.

 

[KlausST]

Hi,

This is quite normal.

1) Your charger has only two connectors for power, thus it has no reference to "earth".
2) your charger is a switch mode device with caoacitive coupling between primary and secondary.
3) to attenuate coupled switching noise there are capacitors between primary and secondary of your charger.

One can not avoid capacitive coupling. And since there is high frequency switching on the primary side. To comply with EMI/EMC regulations one needs to suppress this switching noise coupled to the secondary side.
This is done by the primary-to-secondary-capacitor. It creates a path for the HF back to the primary side. While this reduces the secondary common mode HF ... it sadly creates a path for mains frequency.

So there is voltage (mains frequency) between secondary and earth. But the current is limited to a non dangerous value. Also - because of safety reasons - the capacitors need to comply with safety "X" standards.

In worst case there should be half of the mains voltage between secondary and earth.
But don't be scared of the voltage. As soon as you touch it the voltage will go down.
Mind: Not the voltage is dangerous, but the current.

The current should be below 0.5mA.

******
Better solutions:
* power supplies for medical use will have reduced stray current
* power supplies with earth connector are able to reduce the "voltage against earth"

Klaus

 

[Peter5510]

@KlausST, Thank you for taking time to explain. This handycam is linked to the PC via firewire. This firewire card is more than 10 years old. The PC had several BSOD during video transfer. I change to another card then the problem goes away. It's not the leakage that cause the BSOD.

 

[KlausST]

Hi,

now you talk about BSOD.
And BSOD surely can be caused by discharge currents or (HF) loops.

Discharge current: High voltage on camera_GND (as explained before)
HF-loop via Firewire cable and mains cable.

How "sensitive" this all is depends on each device involved. Thus it´s no surprise that the behaviour changes with a different firewire card.

Klaus