bardsapprentice wrote:
We've lived in a home for 20 years that was built in 1970. It has
aluminum wiring. Over the years we have a consistent problem with a
kitchen light in the middle of the ceiling browning out after we turn
it on. It turns on just fine and a few seconds later it dims and then
goes back to full light. It might never do it again or it might repeat
this. We've been unable to establish a pattern.
....

can you suggest another direction to look?

Well, if other outlets/lights on the circuit are not affected, and
switches/connections to the fixture in question didn't resolve it, it's
isolated to either the fixture itself or in the wiring itself between
the fixture/switch. I'd start by looking a the connections to the
fixture and then suspect the base of the fixture -- bases will oxidize
or the base spring relax, etc.

I wouldn't assume because you haven't had a fire yet you
wouldn't/won't.

My inclination would be to simply replace the fixture if it's just an
ordinary ceiling fixture. If you have a spare or an accessible
porcelin bulb base somewhere, substitute it for a few days and see if
the problem doesn't go away...