For two years I've been running a Directv HD receiver with no problems. Two weeks ago I had a Directv HD DVR installed and now my system sounds like an electric shaver when powered on and off. Directv came back out, did some troubleshooting and discovered a faulty power cord on the new receiver. Two days later, the shaver is back. The only way I've been able to completely distinguish the problem is remove the receiver. Has anyone had this problem? If so, what's the fix?

Sounds like a ground loop issue. Here is some info on it Ground Loop Noise

You can try moving connectors around but probably the easiest fix is getting a ground loop isolator. radio shack carries them and other places usually for under $20.

I'm familiar with the dreaded "ground loop" problem but why? Why is this new device causing a ground loop problem and why wouldn't the Panamax 5400 mask it?

That is beyond my pay grade

Seriously I had a bit of the opposite. I had ground loop problems with my SD DirecTV but when I got HD it seemed to go away.

Hopefully someone else is more knowledgeable than me on this issue.

I've had the same problem, and my Panamax won't filter it either- I've managed to improve on the noise problem, but not eliminate it entirely by regrounding my dish correctly (the DTV tech did a LOUSY job!), and making sure that it's also grounded to the house electrical system. I didn't have much luck with the ground loop isolators- They blocked the signal from the DTV HD dish feed... Good luck, please let us know if & how you fix it!

I recently had a 60hz hum after my house was re-sided. After much troubleshooting it turned out my siders were too lazy to connect the ground cable from the cable demarc on the side of the house to the grounding rod. They just neatly tucked it behind the cable panel and called it good.

So, i soldered the ground from the cable fixture on outside of house to the grounding rod with my plumbing torch and it made a huge improvement. Not all the hum was gone though...

So inside the house i have a 1-3 splitter right by my audio equipment, and if i disconnected the coax from the cable box the hum went away.. so i was pretty sure it was still coming in through the coax wire. On the splitter was a ground connection but i had nothing to ground it to.

Here is what I did, not that i recommend this to others (use at your own risk and all).

I took a 3 prong power cord, cut the female end off and shrink wrapped the hot and neutral and fixed the ground to the splitter and plugged it into the wall thus grounding the coax (again). That took care of the last of the hum.

FWIW.