  Over 2,000 stars were observed for one month with a high enough cadence in
order to look for acoustic modes during the survey phase of the Kepler mission.
Solar-like oscillations have been detected in about 540 stars. The question of
why no oscillations were detected in the remaining stars is still open.
Previous works explained the non-detection of modes with the high level of
magnetic activity. However, the studied stars contained some classical
pulsators and red giants that could have biased the results. In this work, we
revisit this analysis on a cleaner sample of 1,014 main-sequence solar-like
stars. First we compute the predicted amplitude of the modes. We find that the
stars with detected modes have an amplitude to noise ratio larger than 0.94. We
measure reliable rotation periods and the associated photometric magnetic index
for 684 stars and in particular for 323 stars where the mode amplitude is
predicted to be high enough to be detected. We find that among these 323 stars
32% have a magnetic activity level larger than the Sun at maximum activity,
explaining the non-detection of p modes. Interestingly, magnetic activity
cannot be the primary reason responsible for the absence of detectable modes in
the remaining 68% of the stars without p modes detected and with reliable
rotation periods. Thus, we investigate metallicity, inclination angle, and
binarity as possible causes of low mode amplitudes. Using spectroscopic
observations for a subsample, we find that a low metallicity could be the
reason for suppressed modes. No clear correlation with binarity nor inclination
is found. We also derive the lower limit for our photometric activity index (of
20-30 ppm) below which rotation and magnetic activity are not detected. Finally
with our analysis we conclude that stars with a photometric activity index
larger than 2,000 ppm have 98.3% probability of not having oscillations
detected.
