Simrad AP24 “Computer Not Found” error

I did a complete factory reset of my Garmin 7612 to remove the previous owner’s data and update my own. Everything appeared to be fine after the reset on the chart plotters, except now I’m getting a “Computer Not Found” error message on the Simrad. Any one have any ideas? Thanks in advance.

Try turning off all power to the AP24 and AC42/AC12, INCLUDING power to the NMEA 2000 bus. All power off for all-things Simrad. Not just the on/off buttons on the displays, you need to turn off breakers, pull fuses, whatever is needed. Then power back on.

My memory is that the AP24 connects to, and is powered by, a SimNet bus. Simnet is Simrad's implementation of a NMEA 2000 compatible system. The Simnet connectors, unlike other NMEA 2000 and compatible systems, don't screw in or on. Instead, they just push in -- and pull out.

So, I guess my next questions are...

What autopilot computer do you have?
Did you do anything physical other than make menu choices? Peek behind anything? Pull anything out to llook? Etc?

Since the AP24 is displaying thenerror.message, it is receiving power, which means it is connected to the NMEA 2000 -compatible bus, and that bus, itself, is powered.

If you touched anything physical, I'd look there first for an unplugged or loose cable. The AP24 does let one daisy chain off of the back of it, as do many of the Simrad devices. SO, I'd also check the back just to make sure it isn't directly connected to the AP computer in addition to the bus. It is possible the computer connects to the bus via the AP24. Not probable, just possible.

If also want eyes on the AP computer. It probablynhas LED indicators for power and status. I'd check those and then it's connections.

The 7612 is fully compatible with NMEA 2000, so no setting should break anything. It also only has one NMEA 2000 port, so it can't do any daisy-chaining or interfere with the connection between the AP computer and AP24.

Good luck!

Thank you both for the replies. I pushed buttons only and didn’t go behind the cabinet, so hopefully nothing has changed with the wiring (but that doesn’t mean that’s not the problem). I’ll try powering everything down completely and reboot. I hope it’s that simple.

Will report back after the weekend. Thank you both!

My "power it all down" suggestion is because there is/was a bug in the AC12 & AC42 computers that would do exactly this. There is a scenario that I don't currently recall that will lock up the AC and make it un-discoverable by the AP control heads. Power cycling the AC doesn't clear it, so it appears to be a hard problem. After replacing a few ACs as defective, I accidentally discovered that if you power cycle BOTH the power to the AC, AND the power on the N2K/Simnet bus, it would recover the AC. Normally the N2K network is left powered on when you power cycle the AC, and that isn't enough - it will remain locked up. Simrad never fixed it, and I don't know if it carries forward to the newer NAC family of APs.

Thank you twistedtree. I'll be headed to the boat tomorrow and try your suggestion. Will report back. I sincerely thank everyone for the help.

Bill.

FWIW, I leave my AP, including the PH AP24 display (but not the FB or tower displays), powered up 24/7. Every once in a while, when returning to the boat, my AP screen will show that error. Repowering at that display by pushing its power button always resolves the issue for me. This problem has existed since original installation more than 10 years ago. Simrad tech support was not able to explain the problem or suggest a better solution, but did observe that I probably wouldn't have the problem if I didn't leave my system powered on, and that "rebooting" is Microsoft's preferred solution to many of its software problems.

Here are the details from my blog about the issue I had. My guess/hope is that some unusual power-on sequence while you were adding your Garmin triggered the same bug, and full power cycling will recover it. Fingers crossed.


From here https://www.mvtanglewood.com/2015/06/simrad-auto-pilot-bugs.html


Here’s a real doozy. If the NSO is turned on before the AC12 breaker is turned on, the AC12 becomes permanently undiscoverable, locked up, and dead. Even after the AC12 power is on, the NSO will alarm saying there is no AP computer. Turning on either of the AP28s also generated alarms saying there was no AP computer. Shutting everything off and then powering up the AC12 first, followed by the NSO and/or AP28s had the same results – no auto pilot computer. It is forever lost. But, I finally tripped over how to unlock it. If you cycle power on the N2K bus, it would reset. Cycling power on the AC12 didn’t help – it had to be the N2K power. Once N2K power had been cycled, the AC12 would again be discovered as expected provided you always apply power to the AC12 before you turn on the NSO.. How’s that for a screw-ball problem?

Crap! Wish me luck.

System software update maybe ?

Possibly. I’ll try the power reboot first. If that works, I may try to update the Garmin 7612 chart plotters next. And IF that continues to work, I’ll try to figure out how to update the Simrad AP. And if none of that works, I’ll update everything, then try the power reboot. And if that still doesn’t work, I’ll call a tech…

BTW, this is a new to me boat. Hence the reason for the factory settings restore on the chart plotters. Probably should have left well enough alone, but wanted to get rid of the previous owners data and have my own.

You can do the update through the back of the ap24.

you will need to confirm few things first (I am assuming that you have one AP20 boat);
A) Is your AP20 connected via a SimNet bus?
B) Is your AP connected directly to the controller and the Chart plotter (Pass through)?
C) Can you move your rudder with AP20 (do you hear the pump running)?
D) Did check your COM ports on the chart plotter?

Update:

This past weekend I made it back to the boat, powered everything up as suggested in this thread and the fault went away. The control head now sees the computer.

I reviewed the network inventory on both the chart plotter and AP. Garmin showed the Simrad in the NMEA inventory, and Simrad show the Garmin in its inventory.

We took the boat out for a short cruise - AP held and changed course with no problem. When I switched to NAV to track a course in the chart plotter the Simrad gives me a “No NAV Found” (or similar) fault. In other words both units see each other, but they’re not talking to each other.

Any additional words or wisdom are sincerely appreciated. Thanks again for all of your responses and help so far.

Bill.

I'm going to suggest something pretty obvious, so please don't take offense, as I don't know how long you've had this Garmin setup: Have you activated a route on the chartplotter?

I also have an AP24. I just upgraded the rest of my electronics suite but left the AP because it works well. That being said, with the new Furuno suite my AP24 will also periodically display something along the lines of "no nav data" when I try to navigate to programed waypoint. The answer is to go into the AP24 setup menu and do an auto setup. It will search out the connected devices and reconnnect. I can't remember the exact option description, but it's pretty self-explanatory. Only takes a few seconds. My installer said this is a common glitch with the AP24. Hope this helps.

BCRyan:

In my mind I'm saying "of course". But, you've got me thinking... I selected the route, the magenta line for the route appeared on the screen, but I haven't selected "activate" from anywhere. Am I missing something? Never any offense taken - still a newbie.

Thanks.

DPKCK:

I tried that as well. All three of my 7612s appeared, I tried auto, then selected each one by one. Same fault message.

I don't recall Garmin's terminology - it's always catchy, but different from the rest of the industry - but you need to "activate" the route. Only then will the chart plotter start broadcasting nav info. I seem to recall a previous Garmin owner saying it's something like "navigate to"? Hopefully a Garmin owner or two will chime in.


It's also possible that you need to have the route "activated", THEN do the auto config step previously suggested. Unless the Garmin is actively sending nav data, the Simrad may not be able to discover it as a nav source.

whwmsj said:

BCRyan:

In my mind I'm saying "of course". But, you've got me thinking... I selected the route, the magenta line for the route appeared on the screen, but I haven't selected "activate" from anywhere. Am I missing something? Never any offense taken - still a newbie.

Thanks.

Click to expand...

Someone with a Garmin should weigh in, as I'm a TimeZero user. But in that software, you can "select" a route (it turns a different color) but it won't send anything to the AP until you specifically "activate" the route.

Thanks. I’ll look into it.

ISSUE RESOLVED

Following several instructions above related to powering off/on, I got it working.

I powered down everything including the network, then brought the network online, then the Simrad AP computer, then the AP24.

Next, I selected “Auto” in the user setup section; for “Position”, all three of my chart plotters were presented. I looked at each until I identified the master chart plotter and selected it. Same procedure for “Navigation”.

A sincere “Thank You” to everyone that posted. I’m back up and running as before. I couldn’t have done it without your help.

Bill.

Glad you got it working.

Suggest you write all of that down so you don't forget. This is the kind of headache/glitch thtT one missed step due to memory forgetting and you will be back to square one.

C lectric said:

Suggest you write all of that down so you don't forget. This is the kind of headache/glitch thtT one missed step due to memory forgetting and you will be back to square one.

Click to expand...

Yep. And the older we get…