then this should be the first problem you need to solve, usually changing the firmware alone can fix a lot of issues, so you should explain what does it say when you try to change the firmware?
It says "Cannot find Signature", I've tried loading the mac fix fw upgrade first as well and it gives me the same error message.
Before assuming this, test. Simple: disconnect all the other boards and swap cables.
Test each board one by one, and swap data cables one by one, and power cables one by one on all three boards while single connected. Then you will know for sure if the data cable is the culprit. Takes time, but gives you the right answer instead of wild guessing.
I tried this and the data/power cables work on the other two boards, so its not the cables.
Upgrading or downgrading the firmware or factory reset and replace ribbon wire(18 pins)doesn't work you have a faulty temp sensor that is why it gives you 15 temp.
Can you try to increase the fan speed and lower the frequency if you don't know how to do this you can check this method from here
https://bitcointalksearch.org/topic/solution-for-antminer-s9-fans-speed-up-down-every-20-seconds-2690140 you can find the frequency in the same tab.
If still doesn't work you have a hardware issue the only solution is to replace the temp sensor from the hashboard.
Thanks. I tried this as well, isolated only trying to run with the board that gives issues, and the board no longer loads at all when speed and freq are modified, had to reset settings. Miner status pages was showing all values zero.
Will need to look into replacing the temp sensor then, any info/tips on how it should be done?
