I just happen to suddenly have a problem with my spa did a quick search and found that this Marquis spa matches mine exactly --- model, control panel pic and all.

Ok, I moved the hot tub to a new house - wasn't goin to leave it behind. It has been running well for about 4 months. I had not been out there for a month, I went to check on it one day and there was nothing on the display. I checked the breaker in the house = good, GFCI on the back of the house = good, I looked at the 2 visible fuses on the board (noted in pic) = appear to be good. There is no display or response at all from the control panel.

How many possible locations are there to check for power? Is there another fuse blown? The control board is fairly new --> replaced 3 1/2 years ago.

I just found the very same problem with my Marquis Voyage Ultimate Series spa today. The topside control panel display is blank and does not appear to have power. I have power to the circuit board and the fuses have continuity. I am assuming I have a bad control panel. Does anyone know how to check it?

Here is a link to the panel overlay:
http://www.spa-works.com/product.php?productid=4680
Here is the control panel:
http://www.spa-works.com/product.php?productid=4672

You know, I ran into a similar problem after I was fiddling with stuff.

Turns out that the control panels are connected and powered by the grey lines (telephone rj-11 / cat-5 type rj-45) and connectors. I accidentally left one loose, and the zone 2 remote switch wasn't working. I opened it back up, and found that the plug was just a bit loose. Try that?