Reply to thread

That is not a good sign.  That means they don't know what the core problem is (or can't prevent it).  The other problem is it seems they have no buffer stock, rather having to wait for a previously failed unit to be refurbished before swapping out with a newly diagnosed bad one.  If I were cynical, I would say their diagnostic procedure of whether something was "in tolerance" or not might be influenced by their current inventory of work in progress (WIP).