Magical Exploding Laptop

So a week ago I had a rather nasty shock. I was watching a TV show that I was playing on my laptop, which was hooked up to my DVD Recorder via S-Video and composite audio cables. Nothing I hadn’t done a few dozen times before. The difference was: I realized that I had not plugged in the laptop’s power cord. When I proceeded to plug in the laptop — *poof* — sparks flew and smoke rolled out of the laptop from under the headphone jacks. It’s an Acer not a Dell so this was truly a surprise :)

After some minor panicing, I found that the laptop would still boot (thankfully) but the audio was dead. I presume the S-Video port was also dead, but I was not about to test it. Sadly, my DirecTivo was also fried (also connected to the DVD Recorder via S-Video) but the DVD recorder is just fine. The jolt also fried a segment of coax cable between the Tivo and the Satellite dish: Specifically it was the segment that goes from the inside of the house to the grounding block outside.

Read on for all of the gruesome details…

I sent the laptop back since it was still under warranty. Acer support was really excellent in this regard. They even scheduled FedEx to pick it up and ship it back to them for free(!) so I was not out a dime. I am, however, still without the laptop as the Holiday weekend delayed the return shipment. It would have been a 7-day turnaround. Not too shabby. Their support system notified me when they received it and when they shipped it back (both the same day, as a matter of fact.) I’ll know more tomorrow when I actually have the laptop back and can see how well it works. I presume they just swapped out the mainboard.

Unfortunately, the Tivo was two years old. I had to order a replacement off eBay because DirecTV no longer sells DVRs with the Tivo software. We have one of the new R15 “DirecTV Plus DVR” boxes and it sucks in comparison to the Tivo — That’s a rant for another time. I also spent a little time on Saturday replacing the bad segment of coax, which turned out to be pretty simple.

Postmortem on the Tivo revealed that it had fried the motherboard. The hard drive and power supply both appear to be ok. Unfortunately the DirecTivo boxes encrypt the recording based on the motherboard’s serial number, so any recordings that we had previously saved are lost even if I swap hard drives with its replacement.

I read in a few places around the ‘net that this happens more than people would like to admit. Most TV equipment (TVs, DVD Players, Tivos, etc) are not grounded, but S-Video includes a ground wire. If somehow voltage travels across the ground wire (hot ground or hot/neutral reversed on the electrical outlet, power surge, etc) it can fry some or all of the components as way more voltage than was intended to travel over the ground wires tries to find a way to earth.

Moral of the story is: make sure all components are powered off and plugged in before making an S-Video connection! Apparently the reason it had been fine previously is because I had the S-Video port on the laptop off before plugging it in, and because it was plugged into power before powering on the S-Video port, it was grounded.

I can only speculate that the Tivo fried when the surge was trying to find a ground and for whatever reason the shortest path was via the coax to the grounding block outside.

It’s not all bad news though. Because I’ve been without my laptop, I’ve been using my server at home as my desktop, so I have some more updates to make on my Desktop FreeBSD page. Stay tuned…

Update 9/5: I received my laptop as well as the replacement Tivo today, both work fine, but apparently there’s a problem with my Dish’s built-in multiswitch which will require a visit from a DirecTV installer to fix. I thought I had just fried a section of cable, which I had, but I must have left cables swapped on the multiswitch, too.
Kudos to Acer support for their fast turn-around time and getting my laptop fixed right the first time!

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