If you are getting a loud squeal/squelch be sure to check your power supply. This is the most common culprit related to this issue. If it is not outputting 15VDC or if there is a loose part inside, it could be faulty and causing the loud squealing sound. Contact Channel Vision for a replacement. If the power supply is outputting the proper 15VDC please contact Channel Vision directly to troubleshoot the other potential causes.