KAP100 Autopilot rolls back and forth when tracking course

[freff]

My M20J has a KAP100 autopilot.  In HDG, NAV, and APR modes it continuously rolls left and right.  As seen on my attitude indicator, it will roll the plane about 3 degrees to the left and then over to about 1 degree right.  It will track the proper course but does so by gently rolling back and forth.  It takes about 5 seconds to go from one side of the roll to the other.  It does this same back and forth rolling regardless if the NAV source is GPS, VOR, or ILS.

 

In wing leveler mode my AI shows about a 1 or 2 degree left roll.  

 

My local A&P/Avionics shop can't seem to figure out what is causing this behavior.    Any ideas?

 

 

 

[Oldguy]

Every autopilot problem I have ever had was initially diagnosed by a call to Autopilots Central in Tulsa, OK. It might be worth giving them a quick shout to see what their thoughts are.