Question Can I replace an S9J hashboard with an S9 or S9i one?

Hey everyone I found a cheap S9J, but I've never used one before. My experience is only with the S9 and S9i. I did some digging online and it looks like the hash boards might be interchangeable with the S9i? A lot of people are saying it’s just like an overclocked S9i. Can anyone back this up? I want to know if I can swap out the broken boards from my S9/S9i. Thanks!

S9/s9j/s9i hashboard should be compatible did you tried it and get some error like mismatch or mixed board? I suggest if you get this error switch to Braiins OS to bypass this issue.

I have not tried anything yet tbh as I have not got the S9J. I have in the past tried swapping s9 and S9i boards but the heat sinks are physically are different height so not compatible. I presume BrainsOS is on their site somewhere and each model of S9 has its own FW version? Thanks

yes and no braiins has the firmware on their website and does not have multiple s9 firmware they have one inclusive firmware for most every s9 https://braiins.com/os-firmware/download s9,s9i,s9j = yes s9k = no

S9 and S9js are the same hashboard size, S9i is different, it's a bit smaller (the hashboads heat sinks), my information is accurate dating to as far back as maybe 2-3 years ago when I last laid my hands on anything S9, so take it with a grain of salt. However, if you manage to physically fit them, they will work without a problem even with the stock firmware, I still remember scammers putting S9 hahsboards in S9j because the J was selling at a bit higher price, the S9i was always the most expensive among them all because it was unique and they couldn't fit S9 hashboards in it.

Brilliant. Looks simple enough to upgrade via flash by directly or via SD card/inage/jumper pins.

Update- The S9j boards were exactly the same as the my S9. I swapped it for a faulty S9 and it’s running slower/Mhz than the other two? Is the control PCB picking it up?

so three boards 4.4th s9 4.4th s9 4.1th  s9j total 12.9 I put typical numbers that may be close to you if set at full speed. Please let us know your numbers for each board. anything close to what I am listing is likely silicone lottery and the aging process. really way different numbers like 4,4,2 means the low board is failing

I’ve just put an S9J board into a standard S9. The S9 was running at 900w on BrainsOS. The S9J board would not go above 550hz. Flashed with old type FW and it’s rubbing at 14Th stable!

You are going to need to tune that S9j differently,  but it won't be that much of a difference anyway. For you previous comment about S9j being the top end of S9, it actually somewhat is, most people preferre it over the other models, however, because Bitmain designed them in the same size of the old S9, scammers were happy about it, so all used S9js were subject to being S9 (a lot older and thus likely to fail sooner), so at that era people wanted S9is just because they knew they couldnt have been S9s with a fake label, but brand new, they were both almost exactly the same with the J version being slightly more expensive and slightly better in terms of hashrate.