I have an old Pioneer DVR-520 DVD-HDD Recorder which I use every now and then. Lately I can see that the picture quality from the internal tuner has become quite poor over the years. The quality overall is not as sharp as it used to be and there don't seem to have any option to change or tune the contrast or quality.

The TV signal is normal analogue, and passes through the DVR into the TV. I have tested the connection on other DVD Recorders and it looks fine, thus eliminating the issue with the cables or TV connection.

Can anyone suggest anything? Any advice or help will be greatly appreciated.