TZT3 and SCX-20

[jerrmarine]

Hi, got a TZT3 12 with SCX-20. Not sure if this was discussed already but couldn't find a similar thread regarding this issue.
Noticed invalid COG and very high SOG, when vessel is stationary. Is this normal? See attached!
TZT3 is configured to use SCX-20 data as priority, when switched to TZT3's internal receiver, seems to be OK.
What could be wrong with the SCX-20?

 

[Johnny Electron]

My guess is something mounted near the SCX20 is putting out RF or the SCX20 was sealed with sealant and water is getting at the circuits. Do you have photos of the mounting area and the surrounding items?

 

[jerrmarine]

Hi Johnny, thanks. See attached pics. Note that COG is somewhat close to the HDG when underway, but SOG is still way too much.

 

[Johnny Electron]

Not seeing any surrounding items on the boat in those photos, I am likely no help to you. If those are wires behind the unit carrying data or power, it wouldn't be something normal nor recommended.