you can help with this machine. I have read the OM till I'm blue in the face but it is not sinking in.
To see if your HDD is full, select the HDD drive, then press the Display button. If the 515 is on a digital channel, ignore the 1st screen and press Display again until there's a bar of icons at top and a Time remaining section in bottom right. That TR section will show how many hours:min of HDD capacity is left at the currently selected rec mode.
If your HDD shows 0 hours:min, you need to Delete titles. I fill one of my machines up all the time (to use all the bits on the HDD), then use the HDD Menu > Delete all titles options. You can also delete one or Multiple titles by clicking the Title button, then click OK on a title and select one of the Delete options.
If your HDD isn't full, let us know since that might require more troubleshooting.
Be aware that, with the 515 or a FW updated 2160A or 513, you can pre-title your wife's timer rec program so each recorded title has not only the index pic, but a title, day of week, date and time, as described here:
So the HDD is not full, which means something else is wrong.
Just to be sure, I think you mis-spoke when you said you selected a channel then turned the 515 on since you have to do the reverse?
This time, turn 515 on, set channel, select HDD, press REC button on front of machine, and watch TV pic to see if you get the normal red dot and REC indication for 5-6 sec at beginning. You can then STOP the rec test and see if there's a new title.
Not a product rep and never worked for/at or represented any players here.
You need to do that simple REC test detailed above and watch for the red REC dot for 1st 5-6 sec in TV pic.
With the Mag models, you can Delete titles in any order since that will free up large segments of the HDD.
*Best* practice is to watch oldest shows first (logical since they're usually in "serial" order) and Delete after watching.
Pretty "esoteric" and may not be necessary but, once every year or two, it might be a good idea to let the HDD get as full as possible (assuming no massive editing) to keep all the bits "active" on the HDD, as described here.