Galaxy 99 external speaker humm

[mudder]

i bought a used galaxy 99 and it seems to be working pretty good.but when i plug in my external speaker i get a huming sound for some reason.it doesnt do it if it dont have it pluged in.i tryed another speaker but it still does it.why would it be doing this?

[THUMPER]

move the external speaker as far as you can from the radio if it still dose it turn down the rf power

[Phaze91460]

Just a thought, I have a 99v now and when I plugged in my speaker that was already working on the 4600 in the same vehicle it wouldnt work. Seams that the mono plug didnt work. I had to use a stereo plug in the radio. Dont know why, dang radio is mono but ..........