All sound related items don't work and make interference noise?

Got a used logic board to replace a wcdma to a gsm for unlocking. The old IPhone was in perfect condition, all parts now broke working. Then after replacement, of just the logic board, all speakers make a interference like noise instead of what i want and the mic doesn't respond as well. My ear pods receive the interference sound and no mic also. Just seeing if any one has any idea to my problem?? i was very careful and have experience on iPhone 3g and watched a YouTube video while taking it apart and reassembly.