I have a 3 year old 898 plotter sounder. It came with the transom mount transducer, which after some discussion, Humminbird determined was defective and replaced. Since new, this machine has had a very odd habit of losing it's ability to properly display colors, except for a very faded yellow. I also found the transom mount transducer to be so poor in performance, that I gave up entirely and put in an Airmar tilted element thru hull. The thru hull reads bottom at all speeds and it provided much better resolution, at first. Yesterday, the machine was back to it's yellow, all the returns on the sounder are yellow. It does this after it's been on for the whole day, especially if there are a lot of fish around, no sarcasm, quite serious. It's very frustrating. I have reset the machine several times, it's good for a minute or so, but before I can even go back to all the settings, it's yellow again. Any thoughts? I'm not sending the machine back, I commercially fish and can't be without a sounder, so.....