Re the connector, it could be anything. The KFC225 for example uses a weird connector.. search here for “NATO PLUG”. Also, with RS232, there are always two ways to wire a connector (DTE or DCE) according to whether the device-to-computer cable has RX and TX swapped, or not. This stuff is unfortunately my day job 
If anyone has found any KAP140 related IMs or MMs, including the servos, please let me have a copy too since I maintain a collection on a private site, for people stuck in these difficult situations
Peter wrote:
lso, with RS232, there are always two ways to wire a connector (DTE or DCE) according to whether the device-to-computer cable has RX and TX swapped, or not. This stuff is unfortunately my day job
I remember the days when understanding the various signals in the RS232/V.24 interface would make you a datacomm expert.
Yesterday we manged to connect a PC and access the interface on the Autopilot.
There were some errors in the log, but none recent and the older ones not connected to the roll problem.
We could engage and disengage the roll clutch, but when giving commands to drive the roll motor nothing happened.
We tried the similar with the pitch servo and that was running as soon as we gave the command.
We did look into the roll servo. I think it was surprisingly clean and looked good but it’s not working at all.
I think next step will be to change the roll servo.
Did you measure the voltage at the roll servo when you engage it? I would do that before replacing the servo. Also you can bench test the servo.
I would definitely look at troubleshooting that servo – unless you can just get it changed under warranty. They cost a few k and it could be something simple.
Due to the dire situation in Europe on autopilot servicing, there is a “cottage industry” repairing these things… mostly in the former Soviet Bloc although some UK avionics shops have been known to fix them too, obviously unofficially
An exchange roll servo for my SR22 cost € 980, installation was about 2 hours. The startup voltage says it all in most cases – mine should be around 2.2 V but it was 4 V when it didn’t want to run anymore.
An exchange roll servo for my SR22 cost € 980
You have a KAP140 in an SR22? That would be highly unusual.
IME, if one gets a King servo on which the PCB has “burnt out” (a common fault with the KFC225 servos) then HBK deems it BER (beyond economic repair) and they won’t overhaul it. Hence it is worthwhile to at least take a look.
No, I have a Avidyne DFC90, i just can’t believe that the difference in price for a roll servo can be that high.
pmh wrote:
Yesterday we manged to connect a PC and access the interface on the Autopilot.
Did you manage to make your own cable? I couldn’t find any info about the plug or wiring in the MM.
