Code 771 but can still watch at low resolution

Can you swap the two to see if it is a box or wire problem? But in general 771 is a dish alignment problem, there are videos on youtube if you want to try it yourself otherwise you have to call DTV and wait until a CSR can setup a tech visit. 

What receiver (model) did you take out and what receiver (model) did you replace it with? May help others to figure out your issue. 

Assume you performed the “normal” troubleshooting  items - unplug unit for 30 seconds - restart.(if usingGenie unplug  any clients as well -restart main receiver first) 

to check if your satellite needs adjusting - check signal strength in settings here is a link to a video with more info 

https://youtu.be/pHYBNW7CHQg

If your signal strength is poor you  will need to call customer service to have a service tech come out 

Is the dish configuration correct in the satelite setup menu?

Thanks everyone, nothing is working. I've been told I need one or two B-Band converters, but that makes no sense as the previous and older receiver did not.  I have tried several times to arrange a tech to come out, but have unbelievable trouble getting through to the Directv  department. I will dedicate tomorrow to that project, and then look in to another service. Beyond frustrated. I sincerely appreciate everyone's input!

The H/HR23 had the BBC built in, all others non SWM receivers have to have them.