HDMI cable kills computer?

[BEagle]

On 2 occasions I've plugged the AC charger and an HDMI cable (extension to HDMI-to-VGA adapter to VGA monitor) into my back-up laptop, then tried to switch it on, only to find it dead. On both occasions it's had to go back, have a new motherboard, then the joy of reinstalling all those Win10 updates, Office 365, McAfee etc etc.....

Now it's happened again . This time the laptop was running, I didn't have it connected to the AC charger, just plugged in the VGA cable - and it died.

Is it really possible that a VGA cable or the laptop VGA socket can damage the motherboard - surely the laptop would have some internal protection.

This time it'll be exchanged for a different model - fortunately it's all under warranty! But I've ordered a new HDMI extension cable and a different model of HDMI-to-VGA adapter, just in case....

[Jhieminga]

In many laptops connectors are directly mounted on the mainboard. So if you have a so-so soldered connection or weak spot somewhere on the mainboard you could trigger this by pushing against the connector. I hope you will have more luck with your next laptop!

[andytug]

Never heard of plugging any video cable on and completely killing a computer, perhaps the video card alone if there was something faulty in the wiring, but not the whole thing.
Not even sure how you could do such a thing on purpose (by shorting pins, that kind of thing). Sensible precaution to replace the whole lot, though.

[BEagle]

The HDMI socket of my small laptop (Acer Aspire ES1-131) is connected directly to the main board, I gather.

The old HDMI-to-VGA adapter was self powered from the HDMI cable, or could be powered by a 5v USB supply. Hitherto I didn't need to power it from a 5v supply, but will probably power the new one that way, in case the current load to power it was the cause, although I frankly doubt it. The power required is surely miniscule - and in any case, HDMI cables are supposed to be hot-pluggable.

Personally I reckon that the problem was probably as Jhieminga suggests and is a design issue with that model of laptop which has rear mounted HDMI, USB and power sockets.

Hopefully the replacement (Lenovo 100S), which has a side mounted HDMI socket, will cope OK.

[G0ULI]

You need to be careful with USB supplies, particularly the cheap varieties. High voltages can exist between two separate supplies, or between two pieces of equipment. Usually there is not enough current to cause anything more than a tingle but more than enough to kill delicate electronic equipment. Check out YouTube videos by Big Clive about dodgy USB supplies (and much more!).

This may be why your computer has been keeling over, although from what you describe it seems unlikely.

[BEagle]

Thanks for the tip - I hadn't been using a USB power supply to the HDMI-to-VGA adapter, but if I find that the new adapter won't work without a 5v supply, then I'll use the Netgear 5v USB power supply which I've been using with a (now redundant) Ethernet bridge. It's tried and tested, so should be fine. But as I say, I hope that I won't need to use it.