Good day sir, I'm on ship and having VHF model 8800S, two in number and few days back both of my VHF display has weekend, i tried to do with shift key and brilliance but no use, that is for brilliance but i feel that the VHF units display contrast has some problem as we have to look very close to see if we have to change channel. i have checked the manual, for this problem nothing is given in it. Pls help me on this issue.