strange wire on gridseed miner

[TMW2N]

Hi folks
i'm attempting the voltage mod on my 6 gridseeds, and i've opened up number 5, to find an extra wire there, so i'm very reluctant to do anything with it in case it's had some other mod done previously
i bought these used a couple of weeks back.

have any of you seen this extra wire before, or do any of you have any idea what it's for?

Thanks in advance for any assitance

https://i.imgur.com/aQi35Dt.jpg