711c Fail 0001 Drive unit error

[seaveepete]

Hi,
I crossed to the Bahamas today and my 711c stopped working and displayed a "Fail 0001 error. Drive unit error, check drive circuit."
I powered the unit off/on but the error happens each time I power up.
Any troubleshooting tips are appreciated.
Btw, unit has worked fine since 2015.

Thanks!

 

[seaveepete]

update...
After powering cycling the entire electrical system at the dock it no longer gets the error on power-up... at the dock.
We'll see if it actually works tomorrow but I'd still like to know what causes that Fail 0001 error.

 

[Johnny Electron]

The error has to do with the pump/drive unit. 0001 "DRIVE UNIT ERROR" = Turn off power. It could be the pump was pulling too much current than allowed.

 

[seaveepete]

Thanks Johnny.
The AP did work again for a full day of fishing after the power reset but failed again on the crossing home the next day with the same error. Any ideas on how to troubleshoot an intermittent failure like this? Is the pump dying or is the drive circuit in the FAP7002 going bad?
When the 711c powers on the self-test is always successful.

 

[Johnny Electron]

If this is an install that always worked great before, I think it would be more likely to be the pump than the pilot. It sounds like the pump is getting warm through the day of use and then when it need to fight cross currents the pump just doesn't have enough left in it to fight the water when commanded. If this is fairly new install, then I would reevaluate if the pump sizing was correct to begin with. If the pump is under rated it might not have what it takes when confronted with strong currents but is okay for calmer waters. Intermittent problems are the worst. Ensure you have good gauge wire both going to the pump and to the pilot from the mains. Wire that is too small or has corrosion will starve the pilot/pump for current and cause the same type of issue.

 

[seaveepete]

Thanks again Johnny - that's pretty much my theory too - the pump is getting overworked and is a bit tired. Next time it fails I'll need to check if it's getting hot.
This setup has been working fine for 4 years and it has steered over 2000 miles easily. The installation is clean with correct wire gauges and absolutely no corrosion anywhere.
I have the Furuno HRP 11-12 installed but maybe I should be looking at the HRP 17-12. I only have a single SeaStar Tournament series ram on my twin engine setup so the pump does need to work a bit harder. As you mentioned, it works perfectly under calm conditions but recently started having issues when trolling in moderate seas.

 

[Johnny Electron]

I have the Furuno HRP 11-12 installed but maybe I should be looking at the HRP 17-12.

Caution, over rating a pump is just as bad as under rating a pump. If it was working good for four years and you use it a lot, the pump might just need a rebuild. (new seals etc)

 

[seaveepete]

Still having this drive unit fail error - it happens anytime seas are not completely flat.
The real issue is that when the failure occurs it creates a dangerous situation. This has happened 2 times now and each time was scary because it appears that when the failure occurs the AP was trying to turn to correct course but it stays in the turn and does not straighten out.
Also, the warning beep on this failure is barely audible when the boat is running.

 

[Taniwani]

Could be the commutator in the motor burned in a bit in some position. It then fails to start in certain positions. I'd check brushes and commutator.