Have a swm connected to a HR20 a HR22 and a HR23. On the HR20 we get occassional drop aduio and video garbage, this morning I saw a 771A message breifly. On the HR23 I see 771 often and getting worse, to the point the box won't stay on, It'll reboot spontaneously. Haven't seen issues with the HR22 other than the slowness they all have. Could my smw be bad? How would I check?