Hummingbird 788 CIHD GPS Problems

[Kycatalyst]

I was recommended by someone at a shop to come here with my question.
Im having a major problems with my internal GPS on my hummingbird 788CIHD units. They hardly ever connect. One is flush mounted on the bow and the other is flush mounted on the console. The GPS just won't connect and if I start running will go in and out. If I'm sitting still, then the console unit will usually connect but not before 20 mins of sitting in the same spot goes by. It's almost caused a couple accidents and so I'm finally in a spot where I can replace the units. First though I wanted to check and see if there may be a good way to fix the problem I'm having with the GPS. Also I wanted to add a SI unit, but didn't know if I could network them with my current graphs, and what I would need to network them all together. I don't know if I can fix what I've got or if I'm just better buying all new units. Z

Thanks

[Wayne P.]

Number one thing that affects the GPS function is inadequate power. If you did not do the proper wiring, have bad connections, or your battery is weak, that may be your issue.

Yes the 700 series HD units will share data with a Helix model that is Ethernet capable, waypoints with an ONIX too.

[Kycatalyst]

Thanks for the reply, batteries are fully charged. Even have a minnkota 3 bank charger and ran diagnostics and they are all fine. Even had the dealer I bought it off look at the graphs and no luck. There shouldn't be an issue with power, but I'll double check the power cables. This has basically been a problem since I bought the boat new'ish' from the dealer. It was a federation nation boat.

Bigges question would be if i if I tried to hook in a SI unit, would I need to get the networking box? Also would it be worth the $100 for an external GPS puck?

[Wayne P.]

To connect two units together, you just need an Ethernet adapter AS EC QDE for each unit and an Ethernet cable.
You don't have them connected together now???

To have more than two connections, you need the Ethernet Switch AS ETH 5PXG.

Your console unit should have had an external GPS antenna connected and installed at the transom.

Typically a dealer will not do the proper wiring for a sophisticated sonar/GPS unit. Neither unit should be connected to the boat wiring harness.

[Kycatalyst]

So mine were connected and hummingbird customer rep told me that wasn't supposed to be the case for these units? So that's what really has me so confused. They were connected at one point but now are no longer, they were having some problems. That's why I called the hummingbird rep. Also my units have internal GPS and they just don't work well. The bow unit is flush mounted and wide open it almost never gets signal. The console unit does ok but will lose signal a lot, especially when on plane. But the biggest problem was just getting initial signal on GPS. I've been in the middle of north sauty flats on G'ville and can't get GPS signal. That's what I don't know is there something wrong with my units or would it improve my system to get a external GPS puck. But then each unit only has one Ethernet plug so would I have to buy a Ethernet hub to link them all. Would that cause problems with the system again?

That's what has me so confused about them and wondering if I'm not just better of switching to a whole new setup.

[Wayne P.]

Are you using Ethernet or INTERLINK?

[Kycatalyst]

Right now, nothing. Each is its own device at this time. When they were connected, the bow GPS would pick up when the console was. Now though, the bow almost never picks up GPS. To the point I seldom even turn it on.

They were connected via Ethernet.

[Kycatalyst]

So do you happen to think it would be worth spending the money to buy an interlink and external GPS? Or would I bebbetter off just getting some new units. Cause honestly I think I'm just tired of dealing with it.

[Wayne P.]

So do you happen to think it would be worth spending the money to buy an interlink and external GPS? Or would I bebbetter off just getting some new units. Cause honestly I think I'm just tired of dealing with it.

No for INTERLINK. That was discontinued when the XX9 models came out.

My opinion is find out what your GPS issue is by moving the bow unit to the console and console unit to the bow to verify it is a unit problem or your boat wiring. The repair charge is about equal their worth, then you can judge if you want to go farther.

Also with those units, the fit of the power cord plug to the unit is sort of sloppy, and adjusting the two power cord pins in any direction may be the fix. Do it very little and very gently, they still have to line up with the tiny holes in the unit receptacle.

[Kycatalyst]

Thanks I'll give the power plugs a try and swap the units.

[Kycatalyst]

So I swapped the units, the units are connect via Ethernet. As I checked all the wires and they are still connected. The power cords all seem to be fine and there is still no real difference in the units they won't connect to GPS. When I had only the console unit connected it actually got a GPS signal rather quickly, but that was the old bow unit that wouldn't connect. Now with both units hooked up again, even with one off they still won't connect to GPS. Do I need to try and find the Ethernet connection and disconnect them?

[Wayne P.]

So I swapped the units, the units are connect via Ethernet. As I checked all the wires and they are still connected. The power cords all seem to be fine and there is still no real difference in the units they won't connect to GPS. When I had only the console unit connected it actually got a GPS signal rather quickly, but that was the old bow unit that wouldn't connect. Now with both units hooked up again, even with one off they still won't connect to GPS. Do I need to try and find the Ethernet connection and disconnect them?

That would be a good idea. There should be a cable about 12" long attached to the units. Just unscrew the Ethernet cable lock nut and disconnect the Ethernet cable from the Ethernet adapter.
After that do a Restore Defaults with both units.