Dying tumbler on 560 sec?

[chc]

When I crank the engine, some time nothing happen, I either have to hold the key in that position for about 1-2 sec. then the engine will start or I have to turn key back and re-crank it. I have read this is one of the symptoms of faulty tumbler, is this right? The battery is about 2 years old, I only drive this car once a week. At first I thought was a weak battery/recharge, but after a 30 miles drive to work, it still happen sometime. It is a 90' /43000 miles. Any other thought?