My hc600 was giving me slightly blurry day and night pics plus a lot of vertical lines in my night pics. Others here have had the same problem and posted pics. I don't have any handy (edited to add pics). I pulled my hc600 last weekend, then emailed reconyx about my blurry day/night pics and the vertical lines I was getting. After some very prompt email back and forth between my self and their tech support, I was emailed a prepaid ups shipping label.
I live in mn, so they received the package the next day. One very cool thing, their support staff send you an email once the item was received and a url to check the rma status and where it's at in the process. Very cool. Anyway, they got the cam yesterday, tested it, did repairs and then shipped it today. I won't get it back to the woods for a while, but I will report back when I do.
Here are the details of the rma.
Repair Details
Focused lens.
Checked lens focus.
Cleaned image sensor.
Replaced day/night exchanger.
Replaced lens.
Updated firmware

Click this link for the full size image.
http://webpages.charter.net/gregdomeier/deer/reconyx/dayrecon.jpg
Click this link for the full size image.
http://webpages.charter.net/gregdomeier/deer/reconyx/nightrecon.jpg