I recently cleaned the heads of my JVC 30K D-VHS player. I had to clean it twice and an HDNET tape still pixeled once. I watched a regular VHS tape, a bit old, and it looked good, but every now and again it looked like the screen jumped a few lines. Also after using the tape if I was watching a tape (DVHS or VHS) the screen would freeze if I ejected the tape or if I rewound the tape. The tape was used repeatedly at Best Buy for a demo and the VCR was an open box. Could the freezing of the picture be a sign that the firmware is corrupted? How can I tell that this unit has the newer firmware installed?