Well, well,
Pinout of 82C206 made short work of confirming that did lose
backup power. Fault was in the 3.6V battery's plug
contact, wiggled that plug made voltage bounce back and forth.
The board is Asus ISA-386U3Q, 256K cache installed, UMC chipset and
had decaying CMOS battery so I removed it long ago before I put that
board in storage waiting for a case to come along. That time came
when I recently picked up generic plamsa display lunch box case that
have generic 386dx board, not cached. Took new 3.6V nicd battery
pack and spliced in plug to it instead of soldered pack. The mAh
rating is 280mAh instead of puny 60mAh.
I have questions about plamsa display stuff shortly.
Thought this chipset had seperate cmos back up supply pin. Actually
not, this is shared supplies with use of diode.
Cheers, Wizard