We have an old Nexus/ComNav Star depth and speed system that hasn't worked for years and I'd like to get it working as we have recently relocated to a new lake and want to have a better sense of depth. The display works but does show any readings. I've checked connections from the transducers back to the display and everything looks good. So I have a couple of questions:

1. Any advice on the best way to troubleshoot the system or is it time to replace it (doesn't look like they sell Nexus transducers anymore so would need to upgrade the system I think)?
2. Any recommendations for preferred systems/brands to provide depth and speed? Wind data is something that I might consider adding if we are replacing the system but isn't a requirement, is it worth the cost?

Thanks

John