Need an opinion on dual tuner replacement for 510

[theseus]

I have a 510 receiver that I own. It is connected to 2 Dish 500s with DishPro LNBs and a DP34 switch. I would like to get a dual tuner DVR to own and replace my 510, but every time I have gotten a 522 I haven't been able to connect it. The first one was a lease box and the seller returned my money. The second had a bad modulator and Dish wouldn't even activate it.

So should I try for another 522 or is there another receiver that would be better?

 

[KAB]

So should I try for another 522 or is there another receiver that would be better?

625