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-   -   Simrad AP 27 fault (http://www.trawlerforum.com/forums/s4/simrad-ap-27-fault-34029.html)

Delfin 08-17-2017 05:44 PM

Simrad AP 27 fault
 
This will probably be useless information for most everyone, but in the hopes it may come in handy someday for someone....

I have a Simrad AP 25 Autopilot with an AP 27 Handheld next to the pilot's chair. For unexplained reasons, the AP 27 will allow you to plot out a route and it will auto execute at each waypoint without operator input, whereas the AP 25 requires you to acknowledge every waypoint where the turn is greater than 10 degrees if you initiate the route from the AP 25. Needless to say, the Navigate feature on the AP 27 is my preference.

However, on this trip it suddenly started generating "Comm Failure" error messages when in Navigate mode, then a couple of days later started to go blank. The AP 25 continued to work fine, but I figured I was screwed on the handheld because Simrad disposes of all spare parts for any piece of equipment they offer the day they replace it with a new one. Doesn't matter if you bought that piece of Simrad equipment a year before it was sunsetted, Simrad chucks the spare parts rather than going to the expense of providing customer service. Which, by the way, is why you should never, ever buy any product from Simrad, but be that as it may, I found the fault in my unit and it was pretty surprising.

The cable to the handheld consists of 5 tiny conductors, two of which are wrapped in aluminum foil with 2 reinforcing pull strings in the bundle, plus a braided metal shield around the whole bundle, then the insulating plastic. What I found was the source of the problem was that somehow one of those tiny stranded wires was broken inside the bundle. I have no clue how something like this could happen, but it did. Once I cut off about 12" of the cable and carefully re-attached the 5 conductors to the teenie tiny PCB plug everything is back to normal.

Like I said, a one in a million occurrence probably, but if it happened to me, it might happen to someone else on a similar piece of equipment. The tip off that a broken wire might be the problem was that jiggling the wire about 4 inches from where the cable entered the handheld would cause the unit to sporadically light up again. The fault was definitely not at the connector so I concluded it had to be in the cable bundle. Which it was.

Shrew 08-24-2017 09:32 AM

I've had a 'Comm Error' on my Simrad AP since I bought it. The AP wasn't listed as onboard equipment during the sale and the PO stated right up front that it never worked for him either. As a result, I never pursued it as part of the P&S. I've also not gotten around to looking at it either.

This sounds like it might be very helpful information. Many thanks.

Delfin 08-24-2017 11:38 AM

Quote:

Originally Posted by Shrew (Post 586470)
I've had a 'Comm Error' on my Simrad AP since I bought it. The AP wasn't listed as onboard equipment during the sale and the PO stated right up front that it never worked for him either. As a result, I never pursued it as part of the P&S. I've also not gotten around to looking at it either.

This sounds like it might be very helpful information. Many thanks.

There are probably a number of ways to generate a Comm error, but if your unit is an AP27 I would suggest unscrewing the back and fiddling with the 5 wire connection where the conductors plug into the PCB. Simrad used a fitting that depends on the contactors on the plug slicing through the insulation of the conductor to make contact. Seems entirely possible for one of those connections to be unreliable, so you might just play with those to see if it makes the Comm error go away. If, as seems unlikely, you had a break in one of those conductors as I did somewhere in the cord you might find it as I did - twiddle the cord and see if this causes the unit to lose power or behave differently, and if so, the location of the fault might be discoverable. In my case I was lucky because it was located pretty close to the handheld unit so I could cut off a foot or so of cord and reconnect to the plug and see the problem go away.


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