Navnet vx2 BB Radar only working up to 2nm range

[Irish733]

My VX2 rpu015 suffered water ingress and on inspection was deemed to be beyond repair.
Given that i was limited for space and that i wished to retain the blackbox functionality of the system,i purchased a replacement rpu015 from ebay.
I installed the new processor and matched the IP of the processor to my existing radome.
The processor works perfectly in chart plotter mode
The radar mode has full functionality but will only work as it should up to 2nm range
Up to 2nm the echo is strong and will display land and moving targets.
Is there anything i may have overlooked in setup or any ideas on what the issue may be?
Thanks in advance

 

[Johnny Electron]

I recommend you contact your Furuno distributor with photos and your established settings. They might be able to have a better idea with more information. It almost sounds like your magnetron is going out.