I must be part of a peculiar family

On a recent visit to my sister at Nambucca heads, she showed me an odd problem.
She has a standard definition tv ans a vhs recorder.
Reception on all channels is 1st class.
She can record and play back probably most channels ok, (ch 10 tested)
ch 2 is unwatchable on playback; presumably the problem comes at the recording stage.

Tried using a new tape with same results.
If ch 2 reception was poor, that would explain it but as the reception is A grade............
I just can't think of anything to suggest she try other than spending money she doesn't have on new equipment.
Any ideas anyone?