DSC random expansion trouble

[motley me <tommy@xxxxxxxxxxxxxxxxxxxxxx>]

I have a customer with a DSC 864 panel that is getting random expansion
module failures. I have checked everything i know to check and everything
that tech support can think of and i still get the random general system
supervisory on it. It will go in to alarm and reset several times in a row
and then not do it again for days. and it's never at the same times either.

Any ideas of where to look.

I replaced both expansion modules and checked all voltages at the modules.
the only thing left id the keypad.