Laptop Charger Not Working in New Build House

[lost in espace]

I repaired a jack lead for a customer on their laptop, literally just some cables with DC jack on one end and the clip into the motherboard on the other end.

Repair went fine, and it was working perfectly in the office.

Customer has a new build house, year old. Laptop has been working fine up to now, although they did drop it quite hard.

Now the power supply doesn't work on any their sockets. They have 2 electric boards.

Brought it back to the office works fine. Can't figure it out!

[buggalugs]

Customer could be telling porkies, or could be unable to tell if charger is working i.e. looking at the wrong light or something or some other kind of user-style mistake. Could go there with another laptop and/or charger and maybe a socket tester. Could give them another charger out of the bin. Could refund them and tell them to go away.

[OutInTheShed]

My laptop charger is 3 pin mains and the connector to the laptop has a 3rd 'signal' pin.
It's not double insulated.
It claims to work from 100 to 250V AC.

Possibilities I can think of are a fault with your repair, like the signal pin is open or shorted to one of the other pins.
Could this work or not depending on whether Earth and Neutral are very close in potential or not?

Or is there an earth fault at the client's house?