Area 51 R2 R5 case incompatible

User report transplant POGO assembly from R2 case to R5 case, and LED of side panel stops working. 
Other user tried to use R2 FIO to control R5 side panel LED.  no success.

What my next research project aims to accomplish is to understand Dell Area 51 triad side panel and front LED pinout.

The right side panel being closer to FIO uses a short POGO assembly with red 5 pin connector 

whereas the left side panel further from FIO uses a long POGO assembly with white 6 pin connector 

There are 3x2 contact copper prongs of case on each side for the side panels and each side panel has 6 contact pins.

each side panel has three individually programmable LED.

There are 4x front LED (two top, two bottom) connected via either red 5 pin and white 6 pin LED cables to LOGO board.

Top/bottom front LED on the same side are programmed to run at same color.

there are two DP/N for POGO IN R1

1TTK1 ver: 10  for R5

TD2MK ver: X9 or ver: A. for R2

based on user report

ver: 10 is for R5

ver: X9 and ver: A.  is for R2, DP/N TD2MK 

so what is different between the two POGO assembly that makes TD2MK work with R2 FIO only?  apparently TD2MK does not work with R5 FIO.

5 wires of POGO R connect to 6 contact pins and control 3 LED (POGO 1,2,3) independently.

based on close inspection of POGO R circuit board 

for R2, these 5/6 prongs are connected to 5 wires.  I have verified this to be correct using a multimeter

for R5, the prong for POGO3 connected to wire is switched

although the POGO R assembly for R2 and R5 look very similar in macroscopic wiring, the circuit board print has subtly switched one pin of POGO3 to be different in how 5 wires connect to the 6 contact pins, such that the assembly works only with specific case FIO.  Dell's infinite sly way of changing pinout from model to model in display.

if you are observant you may notice Dell uses similar triangular LED for side panel in Aurora R5-R8.  here we may glean some insight into Dell engineering

this assembly has both 5 and 6 wires connector reminiscent of R and L side panel LED wiring of triad.

three LEDs light up three acrylic light ducts to form the three line of lights you see on the outside of side panel

the triad side panel L and R has a triangular light board inside. 

the design is that the panel would work with both L or R 6 prong which are connected via either 6 or 5 wires to FIO.  

it is confirmed that the R side prong only has 5/6 in contact with the POGO R1 cable (5 wires)

L side prong has 6/6 contact with the POGO L1 cable (6 wires)

finally confirmed area 51 R2 side panel LED board.  I was almost going to remove all the screws of one my own side panel to take a peek inside.  thanks to a master who uploaded these rare pictures.

needless to say, the LED board in R5 side panel is likely different and probably says R5 on it.

to use 6 (or 5) wires to control three independent RGB LEDs, the schematic must be quite complex.

this LED board design is totally different from Aurora R5.

side observation:

the LOGO board are also different between R2 and R5. 

LOGO board has four LED sockets, two red (5 pin) for left LEDs and two white (6 pin) for right LEDs.

R2 LOGO board MS-7347

R5/6 LOGO board MS-4438

note the logo board for R5 has "R2" written on it.  

the actual Tron light cable TL-TL (top left), TL-TR, and TL-BL (bottom left), TL-BR all have only 5 wires.  even the white 6 pin connector only has 5 wires.

R5 FIO MS-4440

R2 FIO MS-4346