Let me start by saying this is a recount w/ pics & video of issues I was having after complete tare down of the Spark due to a crash .
Issue #1 esc error (electronic speed control) In the "rebuild kit" for the arm I purchased
1. A new middle frame
2. 2 escs
3. Shell cover
4. 1 motor

After swapping motherboard, gimball & everything else over to the new middle frame I installed the new escs & noticed I had 2 leds on the escs working but they were back right & front left (the ones I just replaced.
I fired up DJI assistant and hooked up the Spark. It wouldnt register the correct firmware or give any detail other than it was connected to the spark.(pic 2)
I then decide to swap the escs so they were both lit up in the front. Both light up in the front now but still getting esc errors and wont take off...time to buy more escs even though they didnt seem damaged in the crash.
The new escs came and I installed them...all escs lit up and the Spark seems healthy. Time for flight. I install the props and throttle up...no lift off.WTF!!!
No more solder! Turns out there are little black prop circular clips that hold the props in place. 2 have white lines on them that match the props with white circles. These clips must go in opposite corners looking at the front of the drone the 1st goes on the right arm/motor.
Flight achieved again!

Pics can be found in the link
https://www.dropbox.com/sh/u57im1v20oomhfc/AABvrXAOvPSLBbvKgOELKfuea?dl=0

Safe travels

Surprised so many ESC's were damaged.  They are normally pretty durable.  Are the power lines to the ESC marked for polarity?  I heard someone mixed them up and burned up an ESC.