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marlahe

Hi Derek,
I have recently replaced my AIS500 with an AIS700. The 500 worked fine in my system for many years until it just recently gave up. I have connected the new AIS700 exactly as the 500 was connected. I.e. connected to an C80 MFD and also to a S3G auto pilot and a VHF. Exactly according to the instructions / diagram submitted in this forum. See attached file. The AIS is also connected to a PC with ProAIS software and Open CPN software with various charts. I.e. the AIS is feeding the PC through the USB cable with GNDSS and AIS data. (the old 500 was connected with a COM to USB cable)
All looks well both on the PCs various softwares as well as on the C80 MFD. All systems are go on the Pro AIS software diagnostic function as well as receiving AIS information from vessels far away. The Open CPN is also showing AIS tagets as expected and so is the C80. However that is until I shut down the PC. Then targets are starting to disappear on the C80. The few targets remaining are eventually only showing MMSI numbers. As soon as I start the PC again all targets start to come back on the C80. I only have to power up the PC and leave it in sleep mode for the C80 targets to show. I.e. the USB cable must have power. I have tried with removing the USB cable all together. Still pore AIS function on the C80. I have tried to disconnect the auto pilot and / or the VHF from the NMEA multiplexer but nothing seems to help. The bitter end is that I need to have the PC powered and the USB cable connected to the AIS to have the AIS targets show up on the C80. (I could probably just connect the USB to a USB power outlet). What is going on? I don't want to be dependant on a powered USB cable to receive AIS targets on the C80.
Please advise what may be the problem and how to fix it.

Sincerely
Lars Hellman