Newbie bought a KSGER T12

[rytenuff]

Hello!
First off, I  consider myself a TOTAL newbie.
After doing much reading in these forums, I purchased a KSGER T12 which the controller display says is a 3.1S. I have done all the safety mods suggested re. earthing and modifying the heat sinks.
My model has an insulated wire connecting the D2 - pad on the controller (D2 is missing) to a large pad on the PSU. My controller pcb is slightly different than just about every other one shown in these forums. My PSU board is 2.04 black. I have attempted to attach pics.
I am wondering why I have this wire and why D2 is missing. I ask as I have not seen this on any other posts/pics.
Thank you to anyone who may be able to settle my curiosity/concern.
After posting I see that my photo attachments did not post. Maybe I don't have enough privileges. I realise this post is useless without the pics but I am not permitted to delete my post. Sorry!

[rytenuff]

Controller looks like this : https://www.eevblog.com/forum/reviews/stm32-oled-digital-soldering-station-for-t12-handle/125/   (second post down)
PSU board looks like this except black: https://www.eevblog.com/forum/reviews/ksger-t12-stm32-v3-1s-soldering-station/msg2873548/#msg2873548

 

 (20200116_122921.jpg.res (1).jpg) Wire is soldered to the pad bottom right corner. Sorry again ! This would not be required if I knew how to post my own pics.)