Fan Settings and Emulators for Antminer S19

Trying to sort out the ohm settings for Antminer S19 fans. Testing fan simulators, but they show fan speeds way off, like in the 8k range, which is weird compared to what Bitmain says. Anyone got data on this?

Why are you using a fan simulator for the S19? Planning on immersion cooling? If that's the case, you could just switch to Braiins OS to avoid the fan issues.

Fan emulators don't rely on resistance for control. They modify the duty cycle in a pulse train to set and report speed. Most work at 1kHz, where 10% means slow and 100% is full speed.

Yeah, it’s for immersion cooling. Some of my spoofers work while others don't. The RPM readings are way off compared to what the manufacturer lists. I was eyeing asic.to firmware but will check out Braiins too. Any idea how much power savings I could get with auto-tuning?

The spoofer has a 1kHz pot to adjust, but I’m stuck figuring out the right ohm values on the multimeter for fan settings. My spoofers seem to mess up the fan failure readings in the ASIC logs.

The resistance of the pot is pretty irrelevant unless you know the rest of the spoofer circuit. It’s part of a timing circuit, so measuring duty cycle and pulse train frequency is key. Use a multimeter with those functions or check the average DC voltage between the yellow tach wire and ground. You can estimate duty cycle from that.

Thanks for the tips, really appreciate it!

You could also just search for 'fan simulator circuit' online to find diagrams or info on fake fan signals. There’s some interesting discussions around.

I haven't tried immersion cooling, but I've tested both firmwares before. Honestly, I think Vnish (asic.to / awesomeminer) is better. Vnish is a modified Bitmain firmware, while BOs+ is built from scratch. Just my preference, though. Both do save power compared to stock firmware.

I don’t own an S19, so I can't say how much power you'd save with auto-tuning on BraiinsOS. But it adjusts settings automatically for each ASIC chip. Cooler miners can give better hashrate and save power, at least based on my experience with the S9.

Just a heads up for the OP, boosting hashrate usually means less efficiency. Custom firmware might be more efficient than stock at the same hashrate. For example, if stock gives 100TH at 3100W, custom could do 100TH at 2900W. Underclocking with custom firmware could mean better efficiency but lower hashrate.

Thanks for the info and links.

Shoutout to mikeywith and BitMaxz for the insights. My goal with firmware is to improve ASIC efficiency. I’ve got a lot of GPU mining experience but still getting the hang of ASIC setups. Gonna test my old S9s in a small immersion tank first.

No problem, keep us posted on your progress. This topic is super relevant for immersion cooling, and some pics of your setup would be cool too.

Definitely will do, I’m excited to share results.

How are you getting 220V from a 3-phase system? Phase to neutral is 220-240V, but phase to phase is 380-400V, right? You might mean 2 gears per phase, which works for S9s, but S19 needs a full 20-amp breaker for one gear. Just making sure you're aware of that.

Nice effort! Gave you some merit points for your contributions. Not sure how the ranking system fully works, but you should be able to post images now.

Thanks, I fixed the image!