I wanted to provide an update. I sent the KC192 out to Bevan in Wichita. Jake replaced various capacitors, resistors, and transistors. He also cleaned up the electrical traces that were corroded from the burst capacitor electrolyte. A bench test on power for about 6 hours showed that everything worked. Total cost was just a little north of $800. I can't recommend Jake and Bevan highly enough! Prompt and courteous emails and phone calls throughout the repair process and the entire transaction was completed in less than a week.
After reinstalling in the plane and testing it, I found some additional problems. The AP will hold a heading, hold altitude, fly a nav source, couple to a localizer/glide slope, couple to a GPS/LPV approach, etc. The problem comes when I try to use the KAS297B altitude preselector. Multiple issues here. It won't capture a preselected altitude, either going up or down. It won't hold a vertical speed, either up or down. And when I press the CWS button to capture the present VS, the number that it is capturing is not accurate. It sometimes shows a climb of 2400fpm. I'm wondering if the issue is with altitude preselector. But there is something else weird going on too. I have a Ryan TCAD device installed. It shows my current altitude after the altimeter setting is input. I've noticed that the altitude will sometimes flash from the correct altitude to some crazy number like FL330, and then back. This makes me wonder if there is something wrong with the altitude encoder or pitot-static system. Any thoughts?