What are the red lights on the S9 antimer syncs?

[sz921]

Hi guys

Id appreciate if someone could explain to me what the three red lights near the syncs are . I have a couple of s9 and one of the machines has the middle red light burnt does that mean the chip is burnt?

I know i can check the antminer ip settings for burnt ciruits but i just tried to change the pool and it wouldnt connect to the internet or show it was working,it also showed the continous decrease of hashrate from 9th/s or 10th/s To 0 as if it were dying

Please advise me on how i can test it

[CryptoCrane]

Are you referring to the red LED on the hashing boards themselves? They should always be lit up red when they have power. If you have one that isn't lighting up, then there may be something wrong with it (but not necessarily).

[sz921]

Yes exactly
But how can i test it to know whats wrong?

[MinerMEDIC]

I've only ever seen FB in use. It is connected to the last ASIC on the board to a pin that indicates that the ASIC is busy.