I recently decided to embark on the immersion of Antminers in mineral oil. Currently I have one S5 running smoothly inside the oil, and I am very satisfied with it. It is averaging 1.3-1.4TH at 40 degrees and the fan is running fine. However, yesterday I tried submerging my first S7 (the variant with only 1 fan), and that didn't go as smoothly. When it's starting up, the fan spins for a few seconds and then stops and continuously tries to boot up. I tried unscrewing the fan from the rig and holding it above the oil. When I did this, the miner started hashing normally.
Basically, I was wondering if anyone had any insight on how to remove or disable the fan on an S7. I tried removing it, but the miner doesn't want to run unless their is an operating fan connected to it. Overheating and fire are obviously non issues if I can maintain 40 degrees. Therefore, I would like to just ditch the fans altogether and just use an external source to circulate the oil. I would appreciate any help you could give me.
At worst case probably read the PWM pin from the miner into an Arduino or similar then feedback a pulse signal to the miner to emulate the Tacho connection from the Arduino.
Should be easy to do in software by say setting miner at 20% then reading tacho pulse frequency on a scope.
Thinking about it you could probably then ditch the PWM pin, leave the miner at way 20% fan speed and just feed a pulse back to the miner.
Something along those lines ......