I found the thermostat blank this morning. The furnace (gas forced) was running from the previous night's setting. Furnace works. Once I shut off breaker all stops of course.
Removed Thermostat, inspected leads all secure in blocks. No batteries or fuse. Programmable 24V in. but no power coming in.
Checked control board in outdoor furnace handler.
Was replaced entirely 16 months ago. Appears undamaged.
Pulled 5Amp fuse. Z pattern clean, clear intact.

Ran meter on thermostat, NO 24V incoming.
Checked meter on electric in to control. Power to furnace and controls.
At control board therm leads read 50Vma (AC10v 2.4 approx) below Ohm strip. For both output on step down transformer and at control board.
No problem with internal wires in unit.

Incoming on unit transformer is at 150Vma (Ac10v 6 approx.)

Connected R and W jumped at thermostat, with power restored, no furnace.
Furnace was running when left in last position from thermostat.
Does not appear to be transformer, or fuse.

Possible control board again?
Still possible thermostat?
Tests I can run? Jumps to test?
Specifics please.
Thank you in advance.