Travelling to India, customs duty pay time

[g4gps]

Hi

I am traveling to India and will be landing in chennai airport at around 4AM from etihad airline. After that I have planned to board train at 7AM from chennai central to coimbatore. As I am taking TV along with me, I might be asked to pay duty tax. I would pay it. But I read in forums that I may need to pay only in SBI counter located inside airport. But I am not sure when would that SBI counter open and will i be able to make it to catch train.

please advice.