Originally Posted by
infrequentflyer789
Originally Posted by
MurphyWasRight 
That exchange was at/after the electrical trim was re-enabled, I believe the 'manual' refers to electrical trim switches.
Disagree. From the report:
At 05:41:46, the Captain asked the First-Officer if the trim is functional. The First-Officer has replied that the trim was not working and asked if he could try it manually. The Captain told him to try. At 05:41:54, the First-Officer replied that it is not working.
From the FDR traces, no electric trim command (autopilot or manual) is recorded between approx 05:41 and 05:43, therefore the above exchange can
only be referring to manual trim with the wheel (unless you are suggesting a simultaneous failure of the trim switches).
You are correct, I did not cross check the times correctly.
This could be explained by the pilot thinking that the cutout switches worked as on the 737NG where it is possible to disable automatic trim inputs using one cutout switch while preserving pilot electicall trim control. This changed on the MAX, either switch disables all electrical trim, no idea why that change was made.
The training slide I saw stated the names had changed but I don't recall seeing a statement on the changed functionality, anyone who has access to the conversion slides please clarify if you can,
From a functional schematic posted on another thread it is likely that this would have disabled the trim switches in a way that they would not show on the FDR, unlike the MCAS attempt at ~ 5:40:45 which did not affect the trim.
This might be part of the answer to 'what were they doing all that time', (mashing on disabled trim switches) while the speed to got even higher before attempting (mechanical) manual trim.