  We have obtained optical spectra of seven stars in the old galactic cluster
M67 that are unusual sources of X-rays, and investigate whether the X-ray
emission is due to magnetic activity or to mass transfer. The two binaries
below the giant branch S1063 and S1113, the giant with the white dwarf
companion S1040 and the eccentric binary on the subgiant branch S1242 show
magnetic activity in the form of Ca II H&K emission and H-alpha emission,
suggesting that their X-rays are coronal. The reason for the enhanced activity
level in S1040 is not clear. The two wide, eccentric binaries S1072 and S1237
and the blue straggler S1082 do not show evidence for Ca II H&K emission. A
second spectral component is found in the spectrum of S1082, most clearly in
the variable H-alpha absorption profile. We interpret this as a signature of
the proposed hot subluminous companion.
