Jon Elson wrote:

Michael A. Terrell wrote:


That sounds like you may have some bad electrolytics on the
conrtroller board. The ESR drops some as they heat up, and start
working.

The main board has dozens of large Tantalum capacitors, and older
tantalum caps tend to fail with various symptoms when not kept
polarized fairly frequently. I already fixed one bad one that was
pretty easy to locate, the postflow timer. This fault, if it is
a capacitor, is going to take more detective work.

The board is conformally coated, so any rework is a very painful
process involving carving the coating off with an X-acto knife.
So, shotgunning all the dozens of caps on the board is not practical.


A hot soldering iron should cut throught the conformal coating. If
it is a hard and shiny coating, GC Printkote Solvent may remove it where
you need to work. If it's the soft rubbery crap, it can cause problems
of it's own. I don't shotgun, I find the failures.


--
You can't have a sense of humor, if you have no sense.