Got a Garmin ... now the A/P is acting up?

[gkainz]

Any thoughts? This is our club's Dakota. The A/P is a King KAP150. Garmin GNS430W just installed - this email is from a club member...
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"The replacement DG was installed yesterday afternoon. Wiring connections at the DG and the AI are secure, but the A/P brain is dead.

Test cycle is normal. "AP ENG" produces a constant, fairly rapid descending left roll, with no apparent limit. (I quit at 60° bank, 10° nose down). HDG and NAV functions causes uncoordinated cyclical rolling left and right to about 45° and erratic pitch action.

Curiosity should be quelled - but if not, the last ditch rescue effort is to pull the circuit breaker. Suggest positive id of this breaker before any "experimental ops".

Until repaired, 3Q is a no-autopilot airplane.

It is strange that the symptoms have grown worse with each Directional Gyro change. "
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[poadeleted20]

Stop payment on the check until the shop that did the installation fixes the problem they created.

 

[kmead]

I seem to fight the KFC150 autopilot a lot. The last time I had this problem,( the pilot said it could do a barrel roll) it was the plug on the back of the AI was not fully snapped. The other common problem is that the computer is not racked in properly in the stack. Since the 430 was added it's possible that the tray for the KAP150 is set back to far or to close to another radio that the connections in back can't be made completely. Grab a 3/32 allen wrench and give it a try.

Kevin