I saw this today and it made me think. Today I talked someone through the log on an Ab72 that panel is 25 to 30 years old. We have allsorts of older panels out there all in good working order, It goes to show a serviced system last way beyond its life expectancy. But it always surprises me when a customer complains that their 30 year old panel needs to be replaced, Ill send them this picture the next time it happens.