Garmin 178c

dutch123 · Posted: Mon Sep 14, 2009 10:47 am Post subject: Garmin 178c

Went out this weekend and the sonar is still weak at best even after replacing the transducer, not sure what would cause this i've tried all settings on the unit and the garmin manual says if the depth flashes the unit is getting a weak signal return but even in 5 feet of water the unit will only display a very weak signal even at full gain. Has anyone had the same experience with this unit? Also I added nobeltec, and it uses the data out wire from the 178c, is it possible that this would affect the units sonar display? Confused

Thanks for your help.

JENAFUFFER · Posted: Thu Nov 05, 2009 6:25 pm Post subject:

Does your 178c work with built in antenna ok ?

Tug · Posted: Thu Nov 05, 2009 8:11 pm Post subject:

Electonics like Sounders start to fade out when the batteries get low.Happened to me.

AK Angler · Posted: Fri Nov 06, 2009 3:08 am Post subject:

I've run a 178c for the past three or four years and haven't run into this problem. What does a weak signal look like on the screen? Static? Loss of bottom lock? If the gain is turned up too high it will show a lot of static. What frequency are you running? Maybe try switching frequencies. And, even though I usually run with the range set in AUTO, sometimes it will lose bottom lock (we get some pretty dramatic depth changes in Prince William Sound). Whenever this happens (and I know I'm no deeper than about 600 feet with a good bottom), I can usually get a lock by manually setting the range and waiting a few seconds. When it re-establishes lock I can then set it back to AUTO and it typically holds.

Is there a difference in signal between running and stopped? Are you sure the transducer is properly aimed? Also, it could be that you are picking up interference from other wiring or devices in the boat. Maybe try rerouting the 'ducer cable away from any power cables or other devices.

AstoriaDave · Posted: Fri Nov 06, 2009 5:29 am Post subject:

dutch,

You've got a short list of things to check from others. Temporarily removing the connection to the Nobeltec might be the first thing to try, if it was working before that installation. I agree something in the transducer-to-unit system might be flawed. Can you temporaily swap in someone else's GPS unit?

If you can prove by a swap-out that the 178C itself is flawed, it might be cost-effective to hit Garmin for a factory checkout: http://www8.garmin.com/support/outofwarranty.html

I'm using a 198C, which is also old technology. But, I own it, and it works well enough that I don't feel the need to flatten my wallet for a better one.

Tug · Posted: Fri Nov 06, 2009 9:40 am Post subject:

If your Garmin has the adapter plug in, remove your Garmin from your boat and plug it in to your computer or your trucks axcessory port.I brought mine to the store where i bought it and he had the adapter for my truck and tested the Garmin.It was a fast check and did not cost anything.