With there not being any frost pattern at all, and with the compressor vibrating as if it is operating, this would be a sealed system failure. This could be a sealed system leak or a restriction. Unfortunately, an EPA-certified technician would be required for further diagnosis and repair.
As this could be caused by a few things sealed system related, including a possible compressor failure, the only thing I could suggest would be that an EPA-certified technician would be needed to proceed any further with diagnosis and repairs.
Unfortunately, any work related to opening and repairing a sealed system is required to be done by an EPA-certified technician by law as seen in Section 608 of the U.S. Federal Clean Air Act. With this being the case, we are unable to provide specific repair information regarding sealed systems.