Batboard

the other day my minitor III alerted and when the dispatch was talking there was a feedback like noise that covered up the dispatcher. the sound only happened when it was receiving a signal. this is not the first time its happened. if any one has any info or know where to find it on this site let me know. i have already tried the search option with no luck.

thanks for your time

brian

update on minitor III.
i took my minitor III apart and noticed that it only made the howling noise when the speaker was touching the houseing that holds the receiver and decoder boards. i have resoldered all the grounding joints on the VCO shield. i also noticed that when i was tapping around the board with a plastic tool i could hear the tapping through the speaker amplified.if you squeez the houseing when there is a signal the sound would go away or it would change pitch. could this be a mechanical problem and not a electrical problem. i would like to try to fix this myself before i have to send it in to a radio shop so any help on this subject would be helpful. thanks

brian