Don't know what "Tiara" is, but those
raymarine displays are getting quite old now, at least 15 years, maybe up to 20?
Check if it still works OK. If it does, no hurry to replace.
If it is not working and the display is faulty, the issue is that other still older
equipment connected to the old unit, is compatible with the new one.
Easiest, but not most economical, would be to do a complete upgrade. You might find that the older transducers (depth and wind) might still
work with the new
gear.