I'm mentioning this because it may help someone in the future. I had just built new switch panels, see http://imgur.com/a/trqQI
and discovered that altitude capture no longer worked. In the past I always used the 'b' key to reset the altimeter and this also synced the KAP 140 Baro to the current pressure. Now I use a push button that triggers a LINDA function to reset the altimeter. Somewhere along the line the Baro in the KAP 140 was not syncing and I did not realize it. I could be wrong, but it appears that if the difference between the altimeter and the KAP 140 is great enough, the capture will not work. I manually changed the Baro on the KAP 140 to be close to the altimeter and now the altitude would capture - and now they also sync regardless if I used the 'b' key or the LINDA button.