Sanguinololu 1.3a 1284p - no power at heatbed. (no replies)

Hi.

Im new in 3d printing and im trying to finish my mendel Prusa with Sanguinololu 1.3a and i have a problem.

There is no power at heatbed. I measured power on hot-end - there is normal 12V. When i measure the power on heatbed there is 0 :(

What should I check? What may be a problem?