Dell Inspiron power supply - Voltage on the 3 pin

Hello.

The case concerns the Dell 90W power supply with a 3-pin plug.
I already know that the mass is on the outside of the plug and the plus is inside, the problem is that I have a voltage of 5.5V on 3 pins, and it should be 0V !?

Somewhere I read that there should be a resistance of 1.8 M between the third pin and ground, in my case it is infinity ...

I would like to know if such a power supply is functional and if something can be damaged when there is voltage on pin 3

Greetings.

Take a photo (of this element) and show what exactly you measure (what and how).

Original power supply?

There is a 1wire chip on the small pin in the dell for identifying the power supply.

the power supply is original dell


the plug looks like this:



there is a mass on the outer wall and a plus on the inside, in the middle of the plug there is a thin pin, i.e.

I used this power supply in a car with an inverter, the inverter burned out, so I wanted to check with a digital meter if nothing happened to the power supply. Between the sides is normally 19.5V, and on the 3rd pin it is just like a colleague previously wrote the 1wire system to identify the power supply, but nowhere have I found a clear answer whether there should be voltage on the 3rd pin or 0V.

There should be 0V on the so-called pin.