A signal detector includes a detector to generate raw decisions based on a read back signal. A post-processor identifies possible defects in the raw decisions. A selector selects a portion of the possible defects, and generates modified decisions by operating on the portion of the possible defects. A decoder generates final decisions based on the modified decisions. An estimator evaluates the final decisions to determine whether a sequence in the read back signal has been decoded to a correct codeword. In response to the sequence in the read back signal being decoded to the correct codeword, the final decisions are output from the signal detector. In response to the sequence in the read back signal not being decoded to the correct codeword, the selector selects another portion of the possible defects for processing by the selector, the decoder, and the estimator.