  V393 Scorpii is a member of the subclass of Algols dubbed Double Periodic
Variables (DPVs). These are semidetached binaries with B-type primaries showing
a long-photometric cycle lasting in average 33 times the orbital period. We
describe the behavior of unreported metallic emission lines in the cool stellar
component of this system. The emissions can be single or double for a same line
and sometimes show velocity shifts regarding the velocity of the center of mass
of the star. In addition, these lines are stronger during the high state. This
behavior suggests the presence of active regions in the surface of the rapidly
rotating A7 donor covering a fraction of the visible hemisphere, which have
larger emissivity during the high state. Our finding supports the recently
proposed dynamo model for the long cycle of DPVs proposed by Schleicher &
Mennickent. The model predicts an increase of the dynamo number of the donor
during epochs of mass transfer in this system, and a theoretical long/orbital
period ratio very close to the observed one at the present system age.
