Thanks @Clayton SF - really helpful notes in case my EE friend is needed!
@Lord Soth - yes, we're on the same page. Thanks for your valuable input here and throughout the tube forums!
@Frank I - huge thanks to you for inviting Decware into the loop here. It's possible this is just bad luck - no assembly process is perfect - but if it's something like we discuss above Steve Deckert needs to know.
@Mad Dude and I have been in touch, and we may have a satisfactory ending in sight...