I recently had issues with my upstairs A/C, the outside condenser unit was shutting off randomly at random times while the internal fan continues to run. (Details in this thread: http://hvac-talk.com/vbb/showthread....s-off-randomly) In a nutshell, I had the A/C tech come back out after I recorded a video of the condenser unit emitting a high pitched screeching/whine sound. He changed out the capacitor, and we were issue-free for a week.

(http://www.youtube.com/watch?v=EJp8QTFWRxg).

This week though it has been not cooling yet again, however I've noticed this is a different issue:

1) Internal fan runs, and so does condenser fan but I do not hear the compressor on. When it is cooling, you can hear the compressor clearly.
2) It doesn't cool at a specific time, around 3-5pm, about half the days this week. Other times in the day have been fine.
3) It hasn't made the screeching sound again.

I feel like the compressor is starting to fail, and maybe the capacitor issues from before which affected the fan, in turn put more wear on the compressor. We have had 104-106+ high temps all week...does the compressor ever fail in relation to the outside temp?

FYI I keep it at 85 deg during the day and 78 at around 5pm. On the weekends (which has followed the afternoon failing pattern) I keep it at 78 all day.

Thanks!