With all the postings about power loss, keys not working and other unit malfunction, I thought it might be wise to have a spare power cable on hand.
One big issue is bent pins or low initial power.
If we remove the unit to a bench, we will have a new power cable, a new power supply.
We can then try to power up the unit in demo mode, independent of the boat, and see what happens.
This is a big step in problem determination. It will split the trouble shooting into either the 1) boat (supply, cable, pins) or 2) the unit.
We should be able to get to the root of the problem quicker, get a fix, and be back in operation with less down time.
Having a spare SD card with a known good recording might also help if we are suspecting a transducer issue.
If you can find an old GR16 as a spare this might aid with problems in this area.
Chuck