When making connections to receivers and amplifiers (especially when working with speaker wires), make sure that the equipment is turned off first. It's not required, but it's a lot safer for you and the equipment in the event that you accidentally touch two speaker wires together. A couple of seconds to hit the power button can save hours of shopping for new equipment.
Discuss "Tip of the Day: Power Off Equipment When Making Connections" here.
Read the article.
You should have included something about HDMI cables. They're not tolerant of ANY voltage fluctuations because they're a crappy design. One of my customers sent an e-mail to ask if I could look at their system- it wasn't working. SHe had told me in Feb that they got an AppleTV and I told her to call when they want it set up. I guess they couldn't wait and when they wanted to use it in another area, they'd unplug it and go. When I got there, the system was definitely not working. The power indicator around the switch wasn't lit at all- no green OR red. When I removed the shelf support pins to lower the front of the shelf and slide the receiver out, I saw that the power cord, ethernet cable, Cable HDMI and HDMI to the TV had been unplugged, Once they were back in place, I saw that there was no IP address, not output to the TV from HDMI, yet it worked with the component video signal. I did a hard reset, reset the network card and saw no change.
My guess is that someone tried to pull the receiver when it was powered up and it slid out, yanking all of the cables.
I sent it in for warranty repair and told her that, under no circumstances, should any cables be inserted/removed when the system is on. The repair would have been over $600 if it had been out of warranty because the main board needed to be replaced.