My last time out the si on my hb899 only works on the left side. The right side is totally black. Tried resetting to factory settings. Also thought the motor could be trimmed down too far. Neither was the problem. Just the left side will work. I just bought a used hb998 which I have not installed. My question is, can I mount the 998 and use the same transducer? That would let me check the transducer w/I replacing it. Anybody have any other suggestions?