I have a complete ST50 system on my sailboat and it worked fine for the first year I bought this sailboat.Then the Navcenter died but all the other instruments (depth, speed etc. ) work still fine, however I cannot make routes and use the autopilot together with the GPS anymore.I took the Navcenter apart and found out that the power supply for the picture tube was the cause ( the flyback had blown) I am looking for help with parts or an old complete Navcenter so I can fix my old system back together. Please let me know, Frank.