Thank you for the detailed reply and insights on how to model the above figure. I have thought of this and consulted this with my supervisor. He mentioned that it is not necessary to model the PCB in detailed as the mass of each component on the PCB is very small. Moreover, we do not have the information of mass and location of each component on the PCB. So the proposed approach to model this is to add a point mass that represents the total mass of the components at the C.G. of the PCB. But you mentioned earlier to create a square imprint in the middle of the PCB. My question is how big should this imprint be? Since as shown in the above figure of the PCB. Should the point mass not be distributed throughout the whole PCB's surface as shown in the below figure? The setting of the point mass is shown in the above screenshot. nWarning message concerning the conflicting conditions.nAfter implementing the changes except the imprint for point mass according to your advice, the phenomenon that I described earlier (Connectors detached from PCB) is gone now. But I still don't understand why the eigenfrequencies for mode 4, 5, 6 are not 0. It should be isn't it? Since it is a free modal analysis? Is there an explanation behind this?nn