KAM
Well-known member
Just setting this up. All working except NMEA. All looks pretty simple but nothing on 4800 or 38400. Have I missed something. All usual checks carried out.
The tx/rx ‘lights’ never lit up on my HP33a unit.All good now but 3 minor bugs. Date field remains blank. TX RX indicators on the radar display inoperative. NMEA connection polarity reversed or manual incorrect but otherwise all seems to be working.
Just helped to fit one of these on a friend's boat and pin 6/7 had too be reversed. I'm not sure if it's the manual that is wrong or if the unit has been wired incorrectly.So I compared the working NMEA signal with the signal coming from the 528A. By watching the multimeter display fluctuations it was possible to see that the polarity was reversed. I double checked and i had not made a mistake. Not sure if the manual is wrong or my unit is wired wrongly but reversing the connections to pins 6 and 7 has resolved the problem. Perhaps anyone else with a 528A could confirm my findings. Thanks for the pointers.