Lowrance HDS yellow screen ?

[Peahead]

The other day my HDS5 was working well but then the right to left scrolling started showing a very low contrast and yellow screen with some red that eventually scrolled the full screen as yellow - you can still just barely see the bottom through the yellow coloured screen and the sounder still displays depth ok - see first photo attached (ignore the occasional white reflection on the screen) The scrolling eventually moved on to the correct screen again but then once again the yellow screen gradually scrolled back into place full screen. Didn't make a difference if I moved to deep or shallow water the yellow screen continued on while using the 200 hz setting ( using either auto or manual depth settings). When I switched transducer setting to 50HZ from my usual 200 HZ setting, I was able to get the screen looking normal again. My 200Hz setting has always worked great without flaw in deep water and in shallow water ( using either auto depth control or manual fixed depth choices) so am wondering has anyone had this issue and if so did you solve it?

I Just had the sounder software updated at HC last month. I didn't have time to tinker with it yet but I may try disconnecting the trans cable from the unit and reconnecting ??... as maybe just a connection issue ?

The second photo shows how the scrolling of the yellow ( and red area) has moved to left ( history) and was eventually being replaced by the proper white ( water ) and signals/ clutter on the far right ( present time )

thx for any opinions or past experiences.....