Welcome. You did not give enough details. Is the problem with both HD outputs (HDMI and component) or just one? If it's the HDMI only you might have a problem with the socket itself, a common issue with the older units. (The solder connections onto the circuit board would break if you put too much pressure on that socket, like when inserting/removing the HDMI plug, wiggling it, etc.) You could use just the component connections in that case for essentially the same picture quality. But if you are also using the surround sound signals over the HDMI connections then replacement is in order. If neither HDMI nor component is working then something else is wrong. Are you sure you have the resolution set to an HD value (not 480i)?
I also owned my 622 when it needed replacement re: the a/m socket problem. That was done within the 1-year warranty period at no cost to me. Call Dish Tech Support to discuss your options with an older unit. Do you have the DHPP service plan? If not you might want to add it. That might reduce your cost for replacement. (Not sure for an out-of-warranty unit.) The replacement cost (if any) will be the same however regardless of whether you lease it or own it. I think the DHPP reduces it to $25 but I'm not sure on that. Perhaps someone else will chime in or confirm that with the Tech Support rep...