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Microsoft Surface tablet killing power supply

Not just the tablet.  The owner may have had a close scrape too....

https://www.youtube.com/watch?v=fSE_Nm7pAw4

Microsoft Surface tablet killing power supply

Comments

I never understand folks who buy a £5 charger for a £800 computer.

Phil Collins

Exactly! Someone's optimism exceeded their wisdom the day that decision was made.

Mike Page

In a domestic environment, you'll never get enough fault current to sustain a real nasty explosion. There might be some outgassing, but nothing like arc-flash where the air's nitrogen burns. Plus in the UK there is a plug fuse.

Mike Page

Mike's Electric Stuff tested it. It reduced the trace's resistance by 40%, increased its thermal mass, and it is essentially free for a wave soldered PCB. Also, remember that the track is significantly longer than the via, so the resistance generated by the vias is minimal https://youtu.be/Gy1K3ayPfOk

David E. Blankenship

Having a heatsink physically bridging the isolation barrier is a bad idea without active steps to avoid it touching stuff. Just because it passes a 500V PAT at the factory is not good enough for a lifetime's use. Heatsinks are heavy, they may shift if the unit is dropped. This is a justification for ongoing PAT tests even on a class II appliance like this charger. Better still don't trust Happy Lucky stuff where mains is involved.

Mike Page

I'm not a fan of adding solder to lightweight tracks to increase area. 1. The tracks themselves are not the weak point but the vias - having approx half the plating thickness. 2. Solder is way less conductive than copper, so it's doing very little anyway. 3. Solder has lower melting and boiling points than copper, so it's more likely to cause a conductive cloud than a weightier copper track. I struggle to see an upside. Am I wrong?

Mike Page

IIUC, a wire on the inductor on the high-voltage side was rubbing against the heat sink, and the insulation was damaged. The heat sink was also connected to a trace on the low-voltage side, for some unknown reason. So current went from the inductor, through the heat sink, to the low-voltage side and then bang.

Michael Dunn

Was watching this when my partners daughter walked in ......"Oh, funny Scottish guy"! So she sat down and watched the rest of the vid with me. She's seen a few of the weekend streams and absolutely loves you

John Carr

I'm a little confused - so the heat sink was connected to the mains neutral? The mains live?

Circuitmike

What's the point of a separation slot cut into the board of you're just going to bridge it with a massive heatsink?

JT

Widows surface tablets deserve killing... but thats just opinion... it is a shame though, from experience i know that the chargers for these tablets and indeed the full scale all in one PCs are terrible, the magnetic connection is a bad idea especially in a workshop where all sorts of bits of metal get magnetised onto them... but as always great and informative video BC, thankyou!

Wolfie RARAR

Why would you risk your expensive tablet and personal safety with a dodgy charger? Btw Edge is a browser not a device.

Gadgetman

Why would you risk your expensive laptop and personal safety with a dodgy charger?

Gadgetman

This is what happens when you buy fake chargers. So don't.

Gadgetman

Ouch.

John Riney

I had an experience like this a few years ago. I was using my laptop while it was plugged into a dodgy charger. When the (metal) laptop chassis touched some grounded metal there was quite a bang! The laptop survived. Here's a picture of the fault; the low voltage heatsink is on the left, and the high voltage on the right: https://hiesey.com/web-public/badcharger.jpg

John Hiesey

I'm waiting for the Shitty Pink Charger from China 2022 remix. I had a cheap microsoft surface charger It nearly blew my fingers off If it were on my lap, It'd burn my knob With the cheap miicrosoft surface charger

Loscha

Probably a legit power supply design that was upsized to charge a surface without proper review and testing, then sold anonymously on the usual sites.

Gavin

The OEM chargers for early Surface models also had a fault that resulted in a recall. There was something wrong with the cord coming from the wall into the brick that caused it to overheat if I remember right. Nothing quite as dramatic as this though, I think...

Nick Loh


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