"Regarding conditions you site for "TR" deployment, I believe you are thinking of conditions for ground spoilers, not TR's. TR's only have to be on the ground, at idle".
From the Flight Manual:
PROVIDING that the following conditions are met, 28V Essential DC Bus power is transmitted via the L TR CONT Circuit Breaker to the left TR arm indicator resulting in the TR ARM light on the pilot's instrument panel to illuminate:
-Left power switch (??) is in the idle position
- Left fire handle is in normal position
- T/REV EMER STOW switch is NOT depressed (and on airplanes SN 1000- 1143 excluding SN 1034 not having ASC 166 Nutcracker No. 3 relay
(on ground configuration) or on airplanes SN 1000-1143 excluding
SN 1034 having ASC 166 and airplanes SN 1034, 1144 and
subsequent.
- Either nutcracker No 3 relay energized (on ground) configuration or TR
wheel speed relay energized (wheel speed above 65 MPH (not knots)
With all the discussion about nutcracker failure or the aircraft being somehow in the air mode -- it appears we do not have enough data to intelligently speculate.
Frank R is correct. If the aircraft is in the ground mode, you can do a reverser check taxiing out -- apparently with either nutcracker #3 relay energized as long as in ground mode..
Confusion continues.