How could one disable the fans on an Antminer S7

[Jackhalo3]

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.

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[Biodom]

did you try setting fan on smallest manual setting possible in the gui.
Some people did 20%, not sure lower than this is possible. In addition, i don't have any experince with single fan models.
they could have a different setup.
Not sure that it would help, but it might since S5 fan did work in the oil somehow.

[flameruk]

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 ......

[gt_addict]

I've recently swapped fans on my S9 for other delta models to reduce fan noise. I can safely say that when I swapped the existing rear Fan for a delta afb1212she it ran quieter and the Rpms were a lot lower.

My point is try a different fan as one that spins slower may well have better static pressure properties so may not causing the rebooting issue.

[flameruk]

In oil immersion would if be better to throw the fans away and use an oil pump to circulate the oil round a small cooling radiator then introduce back to the immersion tank? A decent oil pump would be required but with some small bore tube I would probably make some jets to introduce a high flow over the cards. Just food for thought.

[agentcash]

Cut the blades off the fan so just the center spins.

[Burks]

Cut the blades off the fan so just the center spins.

Nice one!

[takagari]

I've recently swapped fans on my S9 for other delta models to reduce fan noise. I can safely say that when I swapped the existing rear Fan for a delta afb1212she it ran quieter and the Rpms were a lot lower.

My point is try a different fan as one that spins slower may well have better static pressure properties so may not causing the rebooting issue.

I'm really interested in the better fan?
we all know bitmain will buy the cheapest option that will do the job.
So I'm sure there exist, just as efficient or better fans

[gt_addict]

I've recently swapped fans on my S9 for other delta models to reduce fan noise. I can safely say that when I swapped the existing rear Fan for a delta afb1212she it ran quieter and the Rpms were a lot lower.

My point is try a different fan as one that spins slower may well have better static pressure properties so may not causing the rebooting issue.

I'm really interested in the better fan?
we all know bitmain will buy the cheapest option that will do the job.
So I'm sure there exist, just as efficient or better fans

The Delta AFB1212SHE 4 pin 1.60A at 30% fan speed setting ran at 960rpm and worked well. Ive currently got two replacement fans from www.eyeboot.com (klintay on this forum) and they are QFR1212GHE 4pin 2.70A at 25% fan speed setting run at 1800rpm but are nice and quiet unlike the original rear fan which was a JSL unit with a big hub and small blades which whined.

I can recommend the QFR and according the deltas own website the QFR is designed to be quiet and still perform extremely well.

[Jackhalo3]

In oil immersion would if be better to throw the fans away and use an oil pump to circulate the oil round a small cooling radiator then introduce back to the immersion tank? A decent oil pump would be required but with some small bore tube I would probably make some jets to introduce a high flow over the cards. Just food for thought.

That is exactly what I am doing. I just need to find a way to get them to run without fans connected.

[Jackhalo3]

Is there any sort of custom controller that can accept Antminer hashing boards and doesn't require fans? Perhaps a modded firmware that I can install on the miners.

[isoneguy]

In oil immersion would if be better to throw the fans away and use an oil pump to circulate the oil round a small cooling radiator then introduce back to the immersion tank? A decent oil pump would be required but with some small bore tube I would probably make some jets to introduce a high flow over the cards. Just food for thought.

That is exactly what I am doing. I just need to find a way to get them to run without fans connected.

Well, you could switch to the F1 firmware. This will allow you to run 1 fan instead of 2 which might be better than nothing.

I know the folks running sp30's in mineral oil modified or replaced the fans that they were using so they could use them in the oil. I think a very slow moving fan would actually help circulate the oil...allowing for additional overclocking? Let us know...these s7 blades (in theory) could take 800-900 watts ea. if the 3x pci-e plugs meant anything.