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Neptune's Gear · 07-06-2016, 02:46

Rudder response failure can be reported by a few different error conditions. The computers just saying that after a time "instructing" the rudder to move, there is no change in rudder angle. So, the solenoid did not click in ( insufficient power, or faulty - likely a coil), or it did, but the pumps not running, so no hydraulics - faulty cabling to pump, pump problem, or insufficient supply voltage to pump from AC42. The other possible issues are communication from rfu to AC42, a faulty rfu, or a faulty AC42.
The early rfu's were very susceptible to RF issues, esp from SSBs, as they had poor shielding. Yours should be new enough to be after they fixed this problem, unless it came from old stock somewhere?
So, when you have the issue, can you hear the pump? Can you hear the solenoid click in? I'd really suspect the solenoid as most likely to have this type of intermittent problem. If the solenoid was replaced with the drive, then, unfortunately it's wiring or the AC42 itself.
Intermittent issues are a real pita!
Good luck. Let me know if I can help with anything, including parts or info...
Matt

Sent from my iPad using Cruisers Sailing Forum

Fluenta · 07-06-2016, 03:14

Quote:

Originally Posted by Neptune's Gear

Rudder response failure can be reported by a few different error conditions. The computers just saying that after a time "instructing" the rudder to move, there is no change in rudder angle. So, the solenoid did not click in ( insufficient power, or faulty - likely a coil), or it did, but the pumps not running, so no hydraulics - faulty cabling to pump, pump problem, or insufficient supply voltage to pump from AC42. The other possible issues are communication from rfu to AC42, a faulty rfu, or a faulty AC42.
The early rfu's were very susceptible to RF issues, esp from SSBs, as they had poor shielding. Yours should be new enough to be after they fixed this problem, unless it came from old stock somewhere?
So, when you have the issue, can you hear the pump? Can you hear the solenoid click in? I'd really suspect the solenoid as most likely to have this type of intermittent problem. If the solenoid was replaced with the drive, then, unfortunately it's wiring or the AC42 itself.
Intermittent issues are a real pita!
Good luck. Let me know if I can help with anything, including parts or info...
Matt

Sent from my iPad using Cruisers Sailing Forum

Hard to tell if the solenoid is clicking when it fails at sea as it is on the other side of a panel and below the lazerette floor. My suspicion too is that it is wiring - which tests fine for voltage drop etc - or the AC42 itself.

**arisatx** · 07-06-2016, 08:19

Here is the TSB http://cs.simradyachting.com/admin.a...=Download,4056

Here is a copy/paste contents of the TSB:

Technical Bulletin
ESTB1017 - AP24&AP28 with Jefa Drives

The Simrad autopilots AP24 and AP28 are designed to offer advanced and precise steering with a gentle `human' rudder action for small course corrections and immediate powerful action for large and demanding course changes. In combination with Jefa rudder drive units this ensures the optimum steering at any time and in any sea condition.

The autopilot and drive unit are automatically aligned and the power values, including extra margin, are stored in the system during the Dock side / Installation Setup. However, after some time of use, the steering system may require more power and the pilot will at random indicate "Rudder response failure" (or error code 26 in other instruments)

The recommended remedy is a simple "re-alignment", so the drive unit again gets sufficient power. The required operation is the standard rudder test, which is performed at the dock side.

Press MENU > Installation > Rudder drive >Rudder test.

The autopilot will now re-align to the drive unit requirement and automatically store the new settings.

NB! Before performing the rudder test,please make sure that the drive/rudder moves when operating the port and starboard buttons in Stby/NFU mode. If the rudder does not move, a problem within the drive unit or the connection is likely to be the fault.

* * *
There was another thread here on CF where the OP tried this rudder test, failing repeatedly, and convinced Navico to replace the drive unit http://www.cruisersforum.com/forums/...ml#post1900761

**arisatx** · 07-06-2016, 08:37

Fluenta replied:

3) What version of software are you running on the AC42? There was a TSB for certain high stiction rudders. 1.3.02.00. I tried to find the service bulletin but can only find reference to it on old cruising forum posts.

How about on the AP24 and AP28, 1.3.02 as well?

**arisatx** · 07-06-2016, 08:41

Also found this TSB:

http://cs.simradyachting.com/Index.aspx?PageID=99&FilesGallery=Download,9776

Technical Bulletin

No ESTB1211 1st June

New AC12/42 Software, version 1.3.02
The changes made to this AC12/42 software are mainly to enhance the performance when using
Virtual Rudder Feedback (VRF), hence there is no need to update pilots operating with RF300 or
RF25.
However, there is one change that may improve the performance when using DD15 and Jefa DD1
drives if they cause “No rudder response” alarm. See point 2 below.

Improvements and changes:
1. Improved VRF steering performance

2. The “High voltage” setting now offers two
different functions:
It now acts as a minimum voltage (motor
start voltage) allowing you to increase the
value (already set by the automatic rudder
test) if rudder movement is not observed
for small rudder commands.
3. To set a fixed drive voltage; Set ‘High
voltage’ to ‘Sol.’ (Solenoid) and, if needed,
reduce ‘Motor output’ % to required drive
voltage.

This software is backwards compatible with
previous 1.3.00 and 1.3.01 versions.
If upgrading an older AC12 or AC42 having
1.1.xx or 1.2.xx version software, make sure the
control head is also upgraded to 1.3.xx.

AC12 and AC42 shipped from factory with
1.3.02 software will have product code HA.

If you have any queries, or require further details, please contact:
Inge Kvalbein
Product Expert
inge.kvalbein@navico.com

**arisatx** · 07-06-2016, 08:59

Not sure if you need a SW update, but just to keep all this Simrad information together in this one thread...

I believe if you have a Simrad NSS MFD on the network, you can do the update thru it - but in my case, since I only had Simrad AP, I needed their ST10 tool that retails for about $150. That and their SWUP software and ST10 USB driver.

It's a PC to Canbus adapter - I tried both the Maretron and the Actisense units but neither worked with SWUP.

I tried buying it directly from the Simrad website, but they were out of stock, but Chicago Marine Electronics had them (thanks Achillefs!)

Here is a link to the SWUP manual http://cs.simradyachting.com/Index.a...=Download,1237

donradcliffe · 07-06-2016, 09:26

You guys are WAY overthinking this one. The OP says he can move the wheel by hand when the autopilot is engaged and in the failure mode. I got a brand new drive from Simrad which had an intermittent failure in the solenoid, and other people have reported the same problem, so I know they have a bad batch out there.

When my new solenoid failed one day out of Hawaii, I replaced it (a PITA at sea) with the one off the old drive, and that solved the problem for the rest of a 16 day passage. I got a replacement solenoid from Simrad and put it the old drive, but have never used it because of other issues with the drive.

I would be all over Simrad for a new solenoid. In the meantime, I think the suggestion of running your own solenoid wire with an on/off switch straight to 12v is a worthwhile one.

Neptune's Gear · 08-06-2016, 00:47

Quote:

Originally Posted by Fluenta

Hard to tell if the solenoid is clicking when it fails at sea as it is on the other side of a panel and below the lazerette floor. My suspicion too is that it is wiring - which tests fine for voltage drop etc - or the AC42 itself.

Sorry Fluenta, but you'll have to find a way to check the solenoid. It is almost certainly the source of this issue, and it will eventually fail completely.
You DONT need the latest firmware - serial number expansion was the only change from the one you have.

You can get the solenoid coil, or a replacement solenoid from many industrial hydraulics places. Navico don't make them, they are a standard part.

I have over 20,000 nm on one of these pilots,on my own boat, only issue has been - guess what? A failed solenoid coil.

Oh, and in case you didn't notice, I'm also a Navico dealer.

tanglewood · 09-06-2016, 21:51

Quote:

Originally Posted by Fluenta

5) Is 14AWG sufficient for "drive engage"? IAW the installation manual and sufficient for the max 3A that could travel down it. Measured voltage drop was less than 2% when tested using NFU.

Where did the 3A number come from? Did you measure that, or is it from some spec? I ask because I expect that is way over what teh AC42 can drive on the clutch engage terminals. A while back I asked Simrad what the current rating was for the drive engage terminals and as I recall it was at most 1A, and maybe even less.

I'm thinking more and more that this is your problem.

donradcliffe · 10-06-2016, 00:04

The solenoid draws one amp at 12v.

Fluenta · 26-06-2016, 02:32

Quote:

Originally Posted by tanglewood

Where did the 3A number come from? Did you measure that, or is it from some spec? I ask because I expect that is way over what teh AC42 can drive on the clutch engage terminals. A while back I asked Simrad what the current rating was for the drive engage terminals and as I recall it was at most 1A, and maybe even less.

I'm thinking more and more that this is your problem.

I found it in the manual somewhere. I have the wires sized for the 3A number so should be very conservative.

tanglewood · 03-07-2016, 13:28

Quote:

Originally Posted by Fluenta

I found it in the manual somewhere. I have the wires sized for the 3A number so should be very conservative.

Just to be clear, I don't think the wiring is the problem, but rather an inherent limitation in the AC42 for how much of a load it can handle on the clutch enable terminals.

By all outward appearances, the (-) clutch enable terminal is pulled to ground via a transistor when the clutch is enabled. This activates any relay wires across the (+) and (-) terminals. But the transistor has limited current carrying capacity, and if overloaded will not pull the (-) terminal fully to ground. The result can be an unreliable relay activation, and would explain 100% of your symptoms.

Another way you could test for this is as follows. Run a 2 conductor cable from a convenient location near your helm, or other location accessible while underway. Wire the two conductors to the two termanals of a switch.

Run the other end to the AC42. Wire one conductor to the Clutch Enable (-), and the other to the battery (-).

Now go sailing and wait for the AP to malfunction. When it is malfunctioning, turn on the switch. This will decisively ground the (-) side of the enable relay on the steering drive unit. If the pilot starts working again, then you found your problem. My money is on this as the source of your problem.