Sorry in advance for the long post...
I just got off the phone with tech support at KVH, a manufacturer of in-motion satellites for marine, RV, and military use.
The call was regarding one of their satellites that a customer of mine has. The satellite has a board failure internally, and this is the second time for this. I got the same response as last time, which was that it was a power quality problem.
This unit is powered from the 12v.d.c. system on the coach, and their specs indicate a broad operating voltage range. I checked everything again as they requested and all appears to be good.
Now for the good part....
They recommended that I get a isolated power supply, so that this doesn't happen again. So I ask if this is something that they sell, and supprisingly they don't. However, Radio Shack does and the tech goes as far as to give me a part # and price from Radio Shack. He then explains that it needs to be MODIFIED. The modification is simple he says, "all you need to do is break the third prong off the a.c. cord and then the system is isolated!! This will now give you the buffer you need".
I already have one of these on my bench, and it is a REGULATED d.c. power supply with a metal case. Can you believe that people are out spreading this crap!!