Today little accident likely revealed the whole story of failure of this particular unit.
Attempt to connect chassis to 10V LO output lead to immediate 'reboot' of the unit
.
Rather quickly the culprit was found, it was a battery pack:
One of bolts that keep this battery pack shorts single cell to chassis, depending on how it was screwed and addition al unit movements.
Thus, initially burned 1 ohm resistor was likely the consequence of doing the same what I did, but for a longer period of time. Could you imagine, this little mechanical issue lead to whole this story
.